Pp cyclic olefin copolymer pp-layer-compound là gì năm 2024

Kelb, Christian; Rother, Raimund; Schuler, Anne-Katrin; Hinkelmann, Moritz; Rahlves, Maik; Prucker, Oswald; Müller, Claas; Rühe, Jürgen; Reithmeier, Eduard; Roth, Bernhard

2016-03-01

We demonstrate the manufacturing of embedded multimode optical waveguides through linking of polymethylmethacrylate [PMMA] foils and cyclic olefin polymer [COP] filaments based on a lamination process. Since the two polymeric materials cannot be fused together through interdiffusion of polymer chains, we utilize a reactive lamination agent based on PMMA copolymers containing photoreactive 2-acryloyloxyanthraquinone units, which allows the creation of monolithic PMMA-COP substrates through C-H insertion reactions across the interface between the two materials. We elucidate the lamination process and evaluate the chemical link between filament and foils by carrying out extraction tests with a custom-built tensile testing machine. We also show attenuation measurements of the manufactured waveguides for different manufacturing parameters. The lamination process is in particular suited for large-scale and low-cost fabrication of board-level devices with optical waveguides or other micro-optical structures, e.g., optofluidic devices.

• 21 CFR 177.1520 - Olefin polymers. Code of Federal Regulations, 2014 CFR 2014-04-01 ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Olefin polymers. 177.1520 Section 177.1520 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES [CONTINUED] INDIRECT FOOD ADDITIVES: POLYMERS Substances for Use as Basic Components of Single and Repeated Use Food Contact Surfaces § 177.1520 Olefin polymers. The olefi...
• Functionalized linear and cyclic polyolefins DOEpatents Tuba, Robert; Grubbs, Robert H. 2018-02-13 This invention relates to methods and compositions for preparing linear and cyclic polyolefins. More particularly, the invention relates to methods and compositions for preparing functionalized linear and cyclic polyolefins via olefin metathesis reactions. Polymer products produced via the olefin metathesis reactions of the invention may be utilized for a wide range of materials applications. The invention has utility in the fields of polymer and materials chemistry and manufacture.
• Electrochromatography on acrylate-based monolith in cyclic olefin copolymer microchip: an attractive technology. PubMed Ladner, Y; Cretier, G; Faure, K 2015-01-01 Electrochromatography [EC] on a porous monolithic stationary phase prepared within the channels of a microsystem is an attractive alternative for on-chip separation. It combines the separation mechanisms of electrophoresis and liquid chromatography. Moreover, the porous polymer monolithic materials have become popular as stationary phase due to the ease and rapidity of fabrication via free radical photopolymerization. Here, we describe a hexyl acrylate [HA]-based porous monolith which is simultaneously in situ synthesized and anchored to the inner walls of the channel of a cyclic olefin copolymer [COC] device in only 2 min. The baseline separation of a mixture of neurotransmitters including six amino acids and two catecholamines is realized.
• Olefin metathesis for effective polymer healing via dynamic exchange of strong carbon-carbon bonds DOE Office of Scientific and Technical Information [OSTI.GOV] Guan, Zhibin; Lu, Yixuan A method of preparing a malleable and/or self-healing polymeric or composite material is provided. The method includes providing a polymeric or composite material comprising at least one alkene-containing polymer, combining the polymer with at least one homogeneous or heterogeneous transition metal olefin metathesis catalyst to form a polymeric or composite material, and performing an olefin metathesis reaction on the polymer so as to form reversible carbon-carbon double bonds in the polymer. Also provided is a method of healing a fractured surface of a polymeric material. The method includes bringing a fractured surface of a first polymeric material into contact withmore » a second polymeric material, and performing an olefin metathesis reaction in the presence of a transition metal olefin metathesis catalyst such that the first polymeric material forms reversible carbon-carbon double bonds with the second polymeric material. Compositions comprising malleable and/or self-healing polymeric or composite material are also provided.« less
• Metal catalyzed synthesis of hyperbranched ethylene and/or .alpha.-olefin polymers DOEpatents Sen, Ayusman; Kim, Jang Sub; Pawlow, James H.; Murtuza, Shahid; Kacker, Smita; Wojcinski, III, Louis M. 2001-01-01 Oily hyperbranched polymers derived from ethylene, propylene, butene and/or a C.sub.5 -C.sub.24 .alpha.-olefin, and a method for their synthesis, are disclosed. The polymers have non-regular microstructures and are characterized by a ratio [{character pullout}]of methyl hydrogens centered around 0.85 ppm on the 1H-NMR spectra of the polymers relative to total aliphatic hydrogens of from about 0.40 to about 0.65 for polymers derived from ethylene or butene, and a ratio [{character pullout}]of from greater than 0.50 to about 0.65 for polymers derived from propylene. A method for grafting hyperbranched polymers derived from ethylene, propylene, butene and/or a C.sub.5 -C.sub.24 .alpha.-olefin onto aromatic rings in organic molecules and polymers, and the resulting grafted materials, are also disclosed. The hyperbranched polymers and grafted materials are useful, for example, as lubricants and lubricant additives.
• Key product development based on cyclo olefin polymer for LCD-TV NASA Astrophysics Data System [ADS] Konishi, Yuichiro; Kobayashi, Masahi; Arakawa, Kouhei 2006-09-01 Cyclo Olefin Polymer [COP], which was developed by Zeon Corporation, is well known and used as an optical plastic in optical markets, having unique properties such as high light transmission, low water absorption, low birefringence etc. Optes Inc, who is ZEON CORPORATION's affiliate optical parts manufacturer, has succeeded in the development of high performance optical base films. These are used for retardation and polarizing films in LCD's [Liquid Crystal Displays], made from Cyclo Olefin Polymer with own film extrusion technologies. The Optical base film developed by Optes Inc has superior properties compared with those of existing products such as polycarbonate [PC], polyethylene terephthalate [PET] and Triacetate Cellulose [TAC] base in terms of low birefringence, high optical isotropy and high dimensional stability under high humidity and temperature conditions.
• Titanium compounds as catalysts of higher alpha-olefin-based super-high-molecular polymers synthesis NASA Astrophysics Data System [ADS] Konovalov, K. B.; Kazaryan, M. A.; Manzhay, V. N.; Vetrova, O. V. 2016-01-01 The synthesis of polymers of 10 million or more molecular weight is a difficult task even in a chemical lab. Higher α-olefin-based polymer agents of such kind have found a narrow but quite important niche, the reduction of drag in the turbulent flow of hydrocarbon fluids such as oil and oil-products. In its turn, searching for a catalytic system capable to produce molecules of such a high length and to synthesize polymers of a low molecular-mass distribution is part of a global task of obtaining a high-quality product. In this paper we had observed a number of industrial catalysts with respect to their suitability for higher poly-α- olefins synthesis. A number samples representing copolymers of 1-hexene with 1-decene obtained on a previous generation catalyst, a microsphere titanium chloride catalytic agent had been compared to samples synthesized using a titanium-magnesium catalyst both in solution and in a polymer medium.
• Hierarchical assembly of branched supramolecular polymers from [cyclic Peptide]-polymer conjugates. PubMed Koh, Ming Liang; Jolliffe, Katrina A; Perrier, Sébastien 2014-11-10 We report the synthesis and assembly of [N-methylated cyclic peptide]-polymer conjugates for which the cyclic peptide is attached to either the α- or both α- and ω- end groups of a polymer. A combination of chromatographic, spectroscopic, and scattering techniques reveals that the assembly of the conjugates follows a two-level hierarchy, initially driven by H-bond formation between two N-methylated cyclic peptides, followed by unspecific, noncovalent aggregation of this peptide into small domains that behave as branching points and lead to the formation of branched supramolecular polymers.
• Synthesis of interlocked molecules by olefin metathesis NASA Astrophysics Data System [ADS] Clark, Paul Gregory A large body of work in the Grubbs group has focused on the development of functional-group tolerant ruthenium alkylidene catalysts that perform a number of olefin metathesis reactions. These catalysts have seen application in a wide range of fields, including classic total synthesis as well as polymer and materials chemistry. One particular family of compounds, interlocked molecules, has benefitted greatly from these advances in catalyst stability and activity. This thesis describes several elusive and challenging interlocked architectures whose syntheses have been realized through the utilization of different types of ruthenium-catalyzed olefin metathesis reactions. Ring-closing olefin metathesis has enabled the synthesis of a [c2]daisy-chain dimer with the ammonium binding site near the cap of the dimer. A deprotonated DCD possessing such a structural attribute will more forcefully seek to restore coordinating interactions upon reprotonation, enhancing its utility as a synthetic molecular actuator. Dimer functionalization facilitated incorporation into linear polymers, with a 48% size increase of an unbound, extended analogue of the polymer demonstrating slippage of the dimer units. Ongoing work is directed at further materials studies, in particular, exploring the synthesis of macroscopic networks containing the DCD units and analyzing the correlation between molecular-scale extension-contraction manipulations and resulting macro-scale changes. A "clipping" approach to a polycatenated cyclic polymer, a structure that resembles a molecular "charm bracelet", has been described. The use of ring-opening metathesis polymerization of a carbamate monomer in the presence of a chain transfer agent allowed for the synthesis of a linear polymer that was subsequently functionalized and cyclized to the corresponding cyclic analogue. This cyclic polymer was characterized through a variety of techniques, and subjected to further functionalization reactions, affording a cyclic
• Design of direct-vision cyclo-olefin-polymer double Amici prism for spectral imaging. PubMed Wang, Lei; Shao, Zhengzheng; Tang, Wusheng; Liu, Jiying; Nie, Qianwen; Jia, Hui; Dai, Suian; Zhu, Jubo; Li, Xiujian 2017-10-20 A direct-vision Amici prism is a desired dispersion element in the value of spectrometers and spectral imaging systems. In this paper, we focus on designing a direct-vision cyclo-olefin-polymer double Amici prism for spectral imaging systems. We illustrate a designed structure: E48R/N-SF4/E48R, from which we obtain 13 deg dispersion across the visible spectrum, which is equivalent to 700 line pairs/mm grating. We construct a simulative spectral imaging system with the designed direct-vision cyclo-olefin-polymer double Amici prism in optical design software and compare its imaging performance to a glass double Amici prism in the same system. The results of spot-size RMS demonstrate that the plastic prism can serve as well as their glass competitors and have better spectral resolution.
• Low severity coal liquefaction promoted by cyclic olefins. Quarterly report, January--March 1994 DOE Office of Scientific and Technical Information [OSTI.GOV] Curtis, C.W. Previous research has suggested that using a more effective hydrogen donor solvent in the low severity coal liquefaction reaction improves coal conversion. In order to understand the results of these methods, both independently and combined, a factorial experiment was designed. Pretreating coal with hydrochloric and sulfurous acid solutions in both water and methanol is compared with pretreating coal using only methanol and with no pretreatment. The effects of these pretreatments on coal liquefaction behavior are contrasted with the ammonium acetate pretreatment. Within each of these, individual reactions are performed with the hydroaromatic 1,2,3,4-tetrahydronaphthalene [tetralin, TET] and the cyclic olefin 1,4,5,8-tetrahydronaphthalenemore » [isotetralin, ISO]. The final aspect of the factorial experiment is the comparison of Wyodak subbituminous coal [WY] from the Argonne Premium Sample Bank and Black Thunder subbituminous coal [BT] provided by Amoco. Half of the reactions in the matrix have now been completed. In all but one case, Black Thunder-HCl/H{sub 2}O, the ISO proved to be more reactive than TET. After the other four reactions using this combination are complete, the average conversion may be greater with the cyclic olefin. The second part of this paper describes the current and future work with Fourier transform infrared spectroscopy. The objective of this work is to determine the kinetics of reaction of isotetralin at high temperatures and pressures. This quarter combinations of three products typically produced from isotetralin were used in spectral subtraction.« less
• Iron-catalyzed stereospecific activation of olefinic C-H bonds with Grignard reagent for synthesis of substituted olefins. PubMed Ilies, Laurean; Asako, Sobi; Nakamura, Eiichi 2011-05-25 The reaction of an aryl Grignard reagent with a cyclic or acyclic olefin possessing a directing group such as pyridine or imine results in the stereospecific substitution of the olefinic C-H bond syn to the directing group. The reaction takes place smoothly and without isomerization of the product olefin in the presence of a mild oxidant [1,2-dichloro-2-methylpropane] and an aromatic cosolvent. Several lines of evidence suggest that the reaction proceeds via iron-catalyzed olefinic C-H bond activation rather than an oxidative Mizoroki-Heck-type reaction.
• High performance optical materials cyclo olefin polymer ZEONEX NASA Astrophysics Data System [ADS] Obuchi, Kazuyuki; Komatsu, Masaaki; Minami, Koji 2007-09-01 ZEON CORPORATION developed innovative optical plastic Cyclo Olefin Polymer [COP], ZEONEX [R] with own technology in 1990 then started commercial production of ZEONEX [R] for optical applications with its very unique properties such as high light transmission, low birefringence, low water absorption, and high glass-transition temperature etc. ZEONEX [R] exhibits outstanding optical performance even under high humidity and temperature conditions. In order to meet increasing requirements of optical market, ZEON CORPORATION newly developed ZEONEX [R]F52R which has high glass-transition temperature 156 deg. C and shows the feature of very low focal length change after high-temperature and high-humidity test.
• Activation energies of diffusion of organic migrants in cyclo olefin polymer. PubMed Welle, Frank 2014-10-01 Cyclo olefin polymer [COP] is an amorphous polymer with good optical transparency and barrier properties, which is increasingly used for pharmaceutical packaging applications like pre-filled syringes, plastic vials, nutrition bags and blisters as well as for micro-well plates. For regulatory purposes, it is important to know the amount and quantity of compounds which migrate from the polymer into the pharmaceutical product. Within the study, diffusion coefficients of organic [model] compounds in COP at various temperatures were determined and the activation energies of diffusion were calculated according to the Arrhenius approach. Correlations were established between the molecular volume V of the migrating compound and the activation energy of diffusion EA as well as between the pre-exponential factor in the Arrhenius equation D0 and EA. From these correlations a prediction model was established for the migration of organic compounds in COP. This might be a useful tool supporting the evaluation process of COP packed pharmaceutical products. Copyright © 2014 Elsevier B.V. All rights reserved.
• Self-healing polymers-The importance of choosing an adequate healing monomer, and the olefin metathesis polymerization of agricultural oils NASA Astrophysics Data System [ADS] Mauldin, Timothy C. Modern society's immense and ill-fated reliance on petrochemical-based polymeric materials will likely necessitate a shift in polymer production paradigms in the near future. The work presented herein attempts to address this issue via a two-pronged approach. First, efforts to improve the duration of composite materials by incorporation of a self-healing function are discussed, the fruitful application of which can potentially reduce or eliminate the massive carbon footprints associated with the repair/replacement of damaged materials. And second, polymeric materials derived predominately from natural and renewable feedstock-namely vegetable oils---are developed. Early microcapsule-based self-healing materials utilized dicyclopentadiene-filled microcapsules and Grubbs' olefin metathesis catalyst to initiate the healing mechanism. However, the patent-protected catalyst, made from the precious metal ruthenium and sometimes costly ligands, will likely never be inexpensive and therefore limit large-scale applications. Hence, clever approaches to reduce the healing catalyst loading in self-healing polymers are of great interest. To this end, our efforts have revolved around solving the problem of the relatively inefficient use of Grubbs' catalyst during the healing mechanism. Given that the mismatch of the olefin metathesis polymerization and Grubbs' catalyst dissolution [in monomer] kinetics is a known cause of this inefficient use of the catalyst, we attempted to tune the "latency" [i.e. pot life] of the olefin metathesis polymerization to ensure more complete dissolution of catalyst in monomer. In an alternative approach to improving efficient catalyst dissolution, we developed a simple model to predict relative dissolution rates of Grubbs' catalyst in a small library of healing monomers. This model was shown experimentally to be able to aid in the selection of, for example, reactive monomer additives that can yield impressive improvements in catalyst dissolution
• The influence of polymer topology on pharmacokinetics: differences between cyclic and linear PEGylated poly[acrylic acid] comb polymers. PubMed Chen, Bo; Jerger, Katherine; Fréchet, Jean M J; Szoka, Francis C 2009-12-16 Water-soluble polymers for the delivery of chemotherapeutic drugs passively target solid tumors as a consequence of reduced renal clearance and the enhanced permeation and retention [EPR] effect. Elimination of the polymers in the kidney occurs due to filtration through biological nanopores with a hydrodynamic diameter comparable to the polymer. Therefore we have investigated chemical features that may broadly be grouped as "molecular architecture" such as: molecular weight, chain flexibility, number of chain ends and branching, to learn how they impact polymer elimination. In this report we describe the synthesis of four pairs of similar molecular weight cyclic and linear polyacrylic acid polymers grafted with polyethylene glycol [23, 32, 65, 114 kDa] with low polydispersities using ATRP and "click" chemistry. The polymers were radiolabeled with [125]I and their pharmacokinetics and tissue distribution after intravenous injection were determined in normal and C26 adenocarcinoma tumored BALB/c mice. Cyclic polymers above the renal threshold of 30 kDa had a significantly longer elimination time [between 10 and 33% longer] than did the comparable linear polymer [for the 66 kDa cyclic polymer, t[1/2,beta]=35+/-2 h] and a greater area under the serum concentration versus time curve. This resulted in a greater tumor accumulation of the cyclic polymer than the linear polymer counterpart. Thus water-soluble cyclic comb polymers join a growing list of polymer topologies that show greatly extended circulation times compared to their linear counterparts and provide alternative polymer architecture for use as drug carriers.
• The Influence of Polymer Topology on Pharmacokinetics: Differences Between Cyclic and Linear PEGylated Poly[acrylic Acid] Comb Polymers PubMed Central Chen, Bo; Jerger, Katherine; Fréchet, Jean M. J.; Szoka, Francis C. 2009-01-01 Water-soluble polymers for the delivery of chemotherapeutic drugs passively target solid tumors as a consequence of reduced renal clearance and the enhanced permeation and retention [EPR] effect. Elimination of the polymers in the kidney occurs due to filtration through biological nanopores with a hydrodynamic diameter comparable to the polymer. Therefore we have investigated chemical features that may broadly be grouped as “molecular architecture” such as: molecular weight, chain flexibility, number of chain ends and branching, to learn how they impact polymer elimination. In this report we describe the synthesis of four pairs of similar molecular weight cyclic and linear polyacrylic acid polymers grafted with polyethylene glycol [23, 32, 65, 114 kDa] with low polydispersities using ATRP and “click” chemistry. The polymers were radiolabeled with 125I and their pharmacokinetics and tissue distribution after intravenous injection were determined in normal and C26 adenocarcinoma tumored BALB/c mice. Cyclic polymers above the renal threshold of 30kDa had a significantly longer elimination time [between 10 to 33 % longer] than did the comparable linear polymer [for the 66 kDa cyclic polymer, t1/2, β= 35 ± 2 h] and a greater area under the serum concentration time curve. This resulted in a greater tumor accumulation of the cyclic polymer than the linear polymer counterpart. Thus water-soluble cyclic comb polymers join a growing list of polymer topologies that show greatly extended circulation times compared to their linear counterparts and provide alternative polymer architecture for use as drug carriers. PMID:19465070

1. Stereospecific olefin polymerization catalysts

   DOEpatents Bercaw, John E.; Herzog, Timothy A. 1998-01-01 A metallocene catalyst system for the polymerization of .alpha.-olefins to yield stereospecific polymers including syndiotactic, and isotactic polymers. The catalyst system includes a metal and a ligand of the formula

   STR1## wherein: R.sup.1, R.sup.2, and R.sup.3 are independently selected from the group consisting of hydrogen, C.sub.1 to C.sub.10 alkyl, 5 to 7 membered cycloalkyl, which in turn may have from 1 to 3 C.sub.1 to C.sub.10 alkyls as a substituent, C.sub.6 to C.sub.15 aryl or arylalkyl in which two adjacent radicals may together stand for cyclic groups having 4 to 15 carbon atoms which in turn may be substituted, or Si[R.sup.8].sub.3 where R.sup.8 is selected from the group consisting of C.sub.1 to C.sub.10 alkyl, C.sub.6 to C.sub.15 aryl or C.sub.3 to C.sub.10 cycloalkyl; R.sup.4 and R.sup.6 are substituents both having van der Waals radii larger than the van der Waals radii of groups R.sup.1 and R.sup.3 ; R.sup.5 is a substituent having a van der Waals radius less than about the van der Waals radius of a methyl group; E.sup.1, E.sup.2 are independently selected from the group consisting of Si[R.sup.9].sub.2, Si[R.sup.9].sub.2 --Si[R.sup.9].sub.2, Ge[R.sup.9].sub.2, Sn[R.sup.9].sub.2, C[R.sup.9].sub.2, C[R.sup.9].sub.2 --C[R.sup.9].sub.2, where R.sup.9 is C.sub.1 to C.sub.10 alkyl, C.sub.6 to C.sub.15 aryl or C.sub.3 to C.sub.10 cycloalkyl; and the ligand may have C.sub.S or C.sub.1 -symmetry. Preferred metals are selected from the group consisting of group III, group IV, group V or lanthanide group elements. The catalysts are used to prepare stereoregular polymers including polypropylene from .alpha.-olefin monomers.

2. Stereospecific olefin polymerization catalysts DOEpatents Bercaw, J.E.; Herzog, T.A. 1998-01-13 A metallocene catalyst system is described for the polymerization of {alpha}-olefins to yield stereospecific polymers including syndiotactic, and isotactic polymers. The catalyst system includes a metal and a ligand of the formula shown wherein: R{sup 1}, R{sup 2}, and R{sup 3} are independently selected from the group consisting of hydrogen, C{sub 1} to C{sub 10} alkyl, 5 to 7 membered cycloalkyl, which in turn may have from 1 to 3 C{sub 1} to C{sub 10} alkyls as a substituent, C{sub 6} to C{sub 15} aryl or arylalkyl in which two adjacent radicals may together stand for cyclic groups having 4 to 15 carbon atoms which in turn may be substituted, or Si[R{sup 8}]{sub 3} where R{sup 8} is selected from the group consisting of C{sub 1} to C{sub 10} alkyl, C{sub 6} to C{sub 15} aryl or C{sub 3} to C{sub 10} cycloalkyl; R{sup 4} and R{sup 6} are substituents both having van der Waals radii larger than the van der Waals radii of groups R{sup 1} and R{sup 3}; R{sup 5} is a substituent having a van der Waals radius less than about the van der Waals radius of a methyl group; E{sup 1}, E{sup 2} are independently selected from the group consisting of Si[R{sup 9}]{sub 2}, Si[R{sup 9}]{sub 2}--Si[R{sup 9}]{sub 2}, Ge[R{sup 9}]{sub 2}, Sn[R{sup 9}]{sub 2}, C[R{sup 9}]{sub 2}, C[R{sup 9}]{sub 2}--C[R{sup 9}]{sub 2}, where R{sup 9} is C{sub 1} to C{sub 10} alkyl, C{sub 6} to C{sub 15} aryl or C{sub 3} to C{sub 10} cycloalkyl; and the ligand may have C{sub S} or C{sub 1}-symmetry. Preferred metals are selected from the group consisting of group III, group IV, group V or lanthanide group elements. The catalysts are used to prepare stereoregular polymers including polypropylene from {alpha}-olefin monomers.
3. Gum formation tendencies of olefinic structures in gasoline and synergistic effect of sulphur compounds DOE Office of Scientific and Technical Information [OSTI.GOV] Nagpal, J.M.; Joshi, G.C.; Aswal, D.S. 1995-04-01 The high octane gasoline pool contains varying amounts of cracked naphthas as an important ingredient in formulating high octane lead free gasoline. The cracked naphthas are largely from Fluidized Catalytic Cracking [FCC] units and to lesser extend from thermal cracking units. While the role of olefinic unsaturation in gum formation during storage of gasoline has been extensively studied, there is little published work on contribution of individual olefin types in storage stability and gum formation tendency of gasoline containing these compound types. In the present work we report our results on storage stability and gum formation tendency of different olefinmore » types present in cracked naphthas through model compound matrix. It is found that cyclic olefins and cyclic diolefins are the most prolific gum formers. We have also studied the role of sulfur compounds present in the gasolines on gum formation tendency of olefins. While thiols enhance gum formation from all olefinic types, sulfides and disulfides interact depending on the structure of olefins. These can have either an accelerating, or inhibiting effect on gum formation.« less
4. Sequence-Controlled Polymerization on Facially Amphiphilic Templates at Interfaces DTIC Science & Technology 2016-06-14 controlled chain growth polymerization. We will synthesize a ?- conjugated “parent” polymer by iterative exponential growth [IEG], attach cyclic olefin...template that is programmed to direct sequence- controlled chain growth polymerization. We will synthesize a ?- conjugated “parent” polymer by iterative...polymerization. We will synthesize a π- conjugated “parent” polymer by organometallic iterative exponential growth [IEG],2 attach cyclic olefin “daughter
5. Surface functionalization of cyclic olefin copolymer with aryldiazonium salts: A covalent grafting method NASA Astrophysics Data System [ADS] Brisset, Florian; Vieillard, Julien; Berton, Benjamin; Morin-Grognet, Sandrine; Duclairoir-Poc, Cécile; Le Derf, Franck 2015-02-01 Covalent immobilization of biomolecules on the surface of cyclic olefin copolymer [COC] is still a tough challenge. We developed a robust method for COC surface grafting through reaction with aryldiazonium. Chemical diazonium reduction generated an aryl radical and the formation of a grafted film layer on the organic surface. We also demonstrated that the chemical reduction of diazonium salt was not sufficient to form a film on the COC surface. UV illumination had to be combined with chemical reduction to graft an aryl layer onto the COC surface. We optimized organic film deposition by using different chemical reducers, different reaction times and reagent proportions. We characterized surface modifications by fluorescence microscopy and contact angle measurements, infrared spectroscopy, X-ray photoemission spectroscopy and Raman spectroscopy, and assessed the topography of the aryl film by atomic force microscopy. This original strategy allowed us to evidence various organic functions to graft biomolecules onto COC surfaces with a fast and efficient technique.
6. Living olefin polymerization processes DOEpatents Schrock, Richard R.; Baumann, Robert 1999-01-01 Processes for the living polymerization of olefin monomers with terminal carbon-carbon double bonds are disclosed. The processes employ initiators that include a metal atom and a ligand having two group 15 atoms and a group 16 atom or three group 15 atoms. The ligand is bonded to the metal atom through two anionic or covalent bonds and a dative bond. The initiators are particularly stable under reaction conditions in the absence of olefin monomer. The processes provide polymers having low polydispersities, especially block copolymers having low polydispersities. It is an additional advantage of these processes that, during block copolymer synthesis, a relatively small amount of homopolymer is formed.
7. Living olefin polymerization processes DOEpatents Schrock, R.R.; Baumann, R. 1999-03-30 Processes for the living polymerization of olefin monomers with terminal carbon-carbon double bonds are disclosed. The processes employ initiators that include a metal atom and a ligand having two group 15 atoms and a group 16 atom or three group 15 atoms. The ligand is bonded to the metal atom through two anionic or covalent bonds and a dative bond. The initiators are particularly stable under reaction conditions in the absence of olefin monomer. The processes provide polymers having low polydispersities, especially block copolymers having low polydispersities. It is an additional advantage of these processes that, during block copolymer synthesis, a relatively small amount of homopolymer is formed.
8. Living olefin polymerization processes DOEpatents Schrock, Richard R.; Baumann, Robert 2003-08-26 Processes for the living polymerization of olefin monomers with terminal carbon-carbon double bonds are disclosed. The processes employ initiators that include a metal atom and a ligand having two group 15 atoms and a group 16 atom or three group 15 atoms. The ligand is bonded to the metal atom through two anionic or covalent bonds and a dative bond. The initiators are particularly stable under reaction conditions in the absence of olefin monomer. The processes provide polymers having low polydispersities, especially block copolymers having low polydispersities. It is an additional advantage of these processes that, during block copolymer synthesis, a relatively small amount of homopolymer is formed.
9. Living olefin polymerization processes DOEpatents Schrock, Richard R.; Bauman, Robert 2006-11-14 Processes for the living polymerization of olefin monomers with terminal carbon-carbon double bonds are disclosed. The processes employ initiators that include a metal atom and a ligand having two group 15 atoms and a group 16 atom or three group 15 atoms. The ligand is bonded to the metal atom through two anionic or covalent bonds and a dative bond. The initiators are particularly stable under reaction conditions in the absence of olefin monomer. The processes provide polymers having low polydispersities, especially block copolymers having low polydispersities. It is an additional advantage of these processes that, during block copolymer synthesis, a relatively small amount of homopolymer is formed.
10. Theory of chromatography of partially cyclic polymers: Tadpole-type and manacle-type macromolecules. PubMed Vakhrushev, Andrey V; Gorbunov, Alexei A 2016-02-12 A theory of chromatography is developed for partially cyclic polymers of tadpole- and manacle-shaped topological structures. We present exact equations for the distribution coefficient K at different adsorption interactions; simpler approximate formulae are also derived, relevant to the conditions of size-exclusion, adsorption, and critical chromatography. Theoretical chromatograms of heterogeneous partially cyclic polymers are simulated, and conditions for good separation by topology are predicted. According to the theory, an effective SEC-radius of tadpoles and manacles is mostly determined by the molar mass M, and by the linear-cyclic composition. In the interactive chromatography, the effect of molecular topology on the retention becomes significant. At the critical interaction point, partial dependences K[Mlin] and K[Mring] are qualitatively different: while being almost independent of Mlin, K increases with Mring. This behavior could be realized in critical chromatography-for separation of partially cyclic polymers by the number and molar mass of cyclic elements. Copyright © 2015 Elsevier B.V. All rights reserved.
11. Photochemical preparation of olefin addition catalysts NASA Technical Reports Server [NTRS] Gray, Harry B. [Inventor]; Rembaum, Alan [Inventor]; Gupta, Amitava [Inventor] 1978-01-01 Novel polymer supported catalysts are prepared by photo-irradiation of low valent transition metal compounds such as Co.sub.2 [CO].sub.8, Rh.sub.4 [CO].sub.12 or Ru.sub.3 [CO].sub.12 in the presence of solid polymers containing amine ligands such as polyvinyl pyridine. Hydroformylation of olefins to aldehydes at ambient conditions has been demonstrated.
12. Macromolecular 'size' and 'hardness' drives structure in solvent-swollen blends of linear, cyclic, and star polymers. PubMed Gartner, Thomas E; Jayaraman, Arthi 2018-01-17 In this paper, we apply molecular simulation and liquid state theory to uncover the structure and thermodynamics of homopolymer blends of the same chemistry and varying chain architecture in the presence of explicit solvent species. We use hybrid Monte Carlo [MC]/molecular dynamics [MD] simulations in the Gibbs ensemble to study the swelling of ∼12 000 g mol -1 linear, cyclic, and 4-arm star polystyrene chains in toluene. Our simulations show that the macroscopic swelling response is indistinguishable between the various architectures and matches published experimental data for the solvent annealing of linear polystyrene by toluene vapor. We then use standard MD simulations in the NPT ensemble along with polymer reference interaction site model [PRISM] theory to calculate effective polymer-solvent and polymer-polymer Flory-Huggins interaction parameters [χ eff ] in these systems. As seen in the macroscopic swelling results, there are no significant differences in the polymer-solvent and polymer-polymer χ eff between the various architectures. Despite similar macroscopic swelling and effective interaction parameters between various architectures, the pair correlation function between chain centers-of-mass indicates stronger correlations between cyclic or star chains in the linear-cyclic blends and linear-star blends, compared to linear chain-linear chain correlations. Furthermore, we note striking similarities in the chain-level correlations and the radius of gyration of cyclic and 4-arm star architectures of identical molecular weight. Our results indicate that the cyclic and star chains are 'smaller' and 'harder' than their linear counterparts, and through comparison with MD simulations of blends of soft spheres with varying hardness and size we suggest that these macromolecular characteristics are the source of the stronger cyclic-cyclic and star-star correlations.
13. Cyclopentadienyl-containing low-valent early transition metal olefin polymerization catalysts DOEpatents Marks, Tobin J.; Luo, Lubin; Yoon, Sung Cheol 2006-10-10 A catalyst system useful to polymerize and co-polymerize polar and non-polar olefin monomers is formed by in situ reduction with a reducing agent of a catalyst precursor comprising {Cp*MRR'.sub.n}.sup.+{A}.sup.- wherein Cp* is a cyclopentadienyl or substituted cyclopentadienyl moiety; M is an early transition metal; R is a C.sub.1 C.sub.20 hydrocarbyl; R' are independently selected from hydride, C.sub.1 C.sub.20 hydrocarbyl, SiR''.sub.3, NR''.sub.2, OR'', SR'', GeR''.sub.3, SnR''.sub.3, and C.dbd.C-containing groups [R''=C.sub.1 C.sub.10 hydrocarbyl]; n is an integer selected to balance the oxidation state of M; and A is a suitable non-coordinating anionic cocatalyst or precursor. This catalyst system may form stereoregular olefin polymers including syndiotactic polymers of styrene and methylmethacrylate and isotactic copolymers of polar and nonpolar olefin monomers such as methylmethacrylate and styrene.
14. Cyclopentadienyl-containing low-valent early transition metal olefin polymerization catalysts DOEpatents Marks, Tobin J.; Luo, Lubin; Yoon, Sung Cheol 2003-04-08 A catalyst system useful to polymerize and co-polymerize polar and non-polar olefin monomers is formed by in situ reduction with a reducing agent of a catalyst precursor comprising {Cp*MRR'.sub.n }.sup.+ {A}.sup.- wherein Cp* is a cyclopentadienyl or substituted cyclopentadienyl moiety; M is an early transition metal; R is a C.sub.1 -C.sub.20 hydrocarbyl; R' are independently selected from hydride, C.sub.1 -C.sub.20 hydrocarbyl, SiR".sub.3, NR".sub.2, OR", SR", GeR".sub.3, and SnR".sub.3 containing groups [R"=C.sub.1 -C.sub.10 hydrocarbyl]; n is an integer selected to balance the oxidation state of M; and A is a suitable non-coordinating anionic cocatalyst or precursor. This catalyst system may form stereoregular olefin polymers including syndiotactic polymers of styrene and methylmethacrylate and isotactic copolymers of polar and nonpolar olefin monomers such as methylmethacrylate and styrene.
15. Cyclopentadienyl-containing low-valent early transition metal olefin polymerization catalysts DOEpatents Marks, Tobin J.; Luo, Lubin; Yoon, Sung Cheol 2007-01-09 A catalyst system useful to polymerize and co-polymerize polar and non-polar olefin monomers is formed by in situ reduction with a reducing agent of a catalyst precursor comprising {Cp*MRR'.sub.n}.sup.+{A}.sup.- wherein Cp* is a cyclopentadienyl or substituted cyclopentadienyl moiety; M is an early transition metal; R is a C.sub.1 C.sub.20 hydrocarbyl; R' are independently selected from hydride, C.sub.1 C.sub.20 hydrocarbyl, SiR''.sub.3, NR''.sub.2, OR'', SR'', GeR''.sub.3, SnR''.sub.3, and C.dbd.C-containing groups [R''=C.sub.1 C.sub.10 hydrocarbyl]; n is an integer selected to balance the oxidation state of M; and A is a suitable non-coordinating anionic cocatalyst or precursor. This catalyst system may form stereoregular olefin polymers including syndiotactic polymers of styrene and methylmethacrylate and isotactic copolymers of polar and nonpolar olefin monomers such as methylmethacrylate and styrene.
16. Cyclopentadienyl-Containing Low-Valent Early Transition Metal Olefin Polymerization Catalysts DOEpatents Marks, Tobin J.; Luo, Lubin; Yoon, Sung Cheol 2004-06-08 A catalyst system useful to polymerize and co-polymerize polar and non-polar olefin monomers is formed by in situ reduction with a reducing agent of a catalyst precursor comprising {Cp*MRR'.sub.n }.sup.+ {A}.sup.- wherein Cp* is a cyclopentadienyl or substituted cyclopentadienyl moiety; M is an early transition metal; R is a C.sub.1 -C.sub.20 hydrocarbyl; R' are independently selected from hydride, C.sub.1 -C.sub.20 hydrocarbyl, SiR".sub.3, NR".sub.2, OR", SR", GeR".sub.3, SnR".sub.3, and C.dbd.C-containing groups [R"=C.sub.1 -C.sub.10 hydrocarbyl]; n is an integer selected to balance the oxidation state of M; and A is a suitable non-coordinating anionic cocatalyst or precursor. This catalyst system may form stereoregular olefin polymers including syndiotactic polymers of styrene and methylmethacrylate and isotactic copolymers of polar and nonpolar olefin monomers such as methylmethacrylate and styrene.
17. Cyclopentadienyl-containing low-valent early transition metal olefin polymerization catalysts DOEpatents Marks, Tobin J.; Luo, Lubin; Yoon, Sung Cheol 2003-12-30 A catalyst system useful to polymerize and co-polymerize polar and non-polar olefin monomers is formed by in situ reduction with a reducing agent of a catalyst precursor comprising wherein Cp* is a cyclopentadienyl or substituted cyclopentadienyl moiety; M is an early transition metal; R is a C.sub.1 -C.sub.20 hydrocarbyl; R' are independently selected from hydride, C.sub.1 -C.sub.20 hydrocarbyl, SiR".sub.3, NR".sub.2, OR", SR", GeR".sub.3, SnR".sub.3, and C.dbd.C containing groups [R".dbd.C.sub.1 -C.sub.10 hydrocarbyl]; n is an integer selected to balance the oxidation state of M; and A is a suitable non-coordinating anionic cocatalyst or precursor. This catalyst system may form stereoregular olefin polymers including syndiotactic polymers of styrene and methylmethacrylate and isotactic copolymers of polar and nonpolar olefin monomers such as methylmethacrylate and styrene.
18. Rapid bonding enhancement by auxiliary ultrasonic actuation for the fabrication of cyclic olefin copolymer [COC] microfluidic devices NASA Astrophysics Data System [ADS] Yu, H.; Tor, S. B.; Loh, N. H. 2014-11-01 Thermal compression bonding is a straightforward, inexpensive and widely used method for enclosing open microchannels in thermoplastic microfluidic devices. It is advantageous over adhesive, solvent and grafting bonding methods in retaining material homogeneity. However, the trade-off between high bond strength and low microchannel deformation is always a crucial consideration in thermal compression bonding. In this study, an effective method for improving bond strength while retaining the microchannel integrity with negligible distortion is proposed and analyzed. Longitudinal ultrasonic actuation was applied to the preheated cyclic olefin copolymer [COC] substrates to achieve accelerated and enhanced bonding with an ultrasonic welding system. Intimate contact between the bonding surfaces before the ultrasonic actuation was found to be an important prior condition. With improper contact, several bonding defects would occur, such as voids, localized spot melting and edge melting. Under auxiliary ultrasonic vibration, within 10 s, the bond strength developed at the bonding interface could be dramatically improved compared with those achieved without ultrasonic actuation. The enhanced bond strength obtained at a preheating temperature of 20 °C lower than its Tg could be comparable to the strength for pure thermal compression at 5 °C higher than its Tg. It is believed that the ultrasonic energy introduced could elevate the interfacial temperature and facilitate the interdiffusion of molecular chain segments at the interface, consequently resulting in rapidly enhanced bonding. Also, the microchannel distortion after ultrasonic actuation was found to be satisfactory—another important requirement. From dynamic mechanical analysis, the glass transition temperature of COC was found to increase with increasing frequency, and the temperature of the bulk polymer under ultrasonic actuation was still well under Tg; therefore the deformation is minor under ultrasonic
19. Efficient Homodifunctional Bimolecular Ring-Closure Method for Cyclic Polymers by Combining RAFT and Self-Accelerating Click Reaction. PubMed Qu, Lin; Sun, Peng; Wu, Ying; Zhang, Ke; Liu, Zhengping 2017-08-01 An efficient metal-free homodifunctional bimolecular ring-closure method is developed for the formation of cyclic polymers by combining reversible addition-fragmentation chain transfer [RAFT] polymerization and self-accelerating click reaction. In this approach, α,ω-homodifunctional linear polymers with azide terminals are prepared by RAFT polymerization and postmodification of polymer chain end groups. By virtue of sym-dibenzo-1,5-cyclooctadiene-3,7-diyne [DBA] as small linkers, well-defined cyclic polymers are then prepared using the self-accelerating double strain-promoted azide-alkyne click [DSPAAC] reaction to ring-close the azide end-functionalized homodifunctional linear polymer precursors. Due to the self-accelerating property of DSPAAC ring-closing reaction, this novel method eliminates the requirement of equimolar amounts of telechelic polymers and small linkers in traditional bimolecular ring-closure methods. It facilitates this method to efficiently and conveniently produce varied pure cyclic polymers by employing an excess molar amount of DBA small linkers. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
20. Geometric somersaults of a polymer chain through cyclic twisting motions NASA Astrophysics Data System [ADS] Yanao, Tomohiro; Hino, Taiko 2017-01-01 This study explores the significance of geometric angle shifts, which we call geometric somersaults, arising from cyclic twisting motions of a polymer chain. A five-bead polymer chain serves as a concise and minimal model of a molecular shaft throughout this study. We first show that this polymer chain can change its orientation about its longitudinal axis largely, e.g., 120∘, under conditions of zero total angular momentum by changing the two dihedral angles in a cyclic manner. This phenomenon is an example of the so-called "falling cat" phenomenon, where a falling cat undergoes a geometric somersault by changing its body shape under conditions of zero total angular momentum. We then extend the geometric somersault of the polymer chain to a noisy and viscous environment, where the polymer chain is steered by external driving forces. This extension shows that the polymer chain can achieve an orientation change keeping its total angular momentum and total external torque fluctuating around zero in a noisy and viscous environment. As an application, we argue that the geometric somersault of the polymer chain by 120∘ may serve as a prototypical and coarse-grained model for the rotary motion of the central shaft of ATP synthase [FOF1 -ATPase]. This geometric somersault is in clear contrast to the standard picture for the rotary motion of the central shaft as a rigid body, which generally incurs nonzero total angular momentum and nonzero total external torque. The power profile of the geometric somersault implies a preliminary mechanism for elastic power transmission. The results of this study may be of fundamental interest in twisting and rotary motions of biomolecules.

1. Substantially isotactic, linear, alternating copolymers of carbon monoxide and an olefin DOEpatents Sen, Ayusman; Jiang, Zhaozhong 1996-01-01 The compound, [Pd[Me-DUPHOS][MeCN].sub.2 ][BF.sub.4].sub.2, [Me-DUPHOS: 1,2-bis[2,5-dimethylphospholano]benzene] is an effective catalyst for the highly enantioselective, alternating copolymerization of olefins, such as aliphatic .alpha.-olefins, with carbon monoxide to form optically active, isotactic polymers which can serve as excellent starting materials for the synthesis of other classes of chiral polymers. For example, the complete reduction of a propylene-carbon monoxide copolymer resulted in the formation of a novel, optically active poly[1,4-alcohol]. Also, the previously described catalyst is a catalyst for the novel alternating isomerization cooligomerization of 2-butene with carbon monoxide to form optically active, isotactic poly[1,5-ketone]
2. Substantially isotactic, linear, alternating copolymers of carbon monoxide and an olefin DOEpatents Sen, A.; Jiang, Z. 1996-05-28 The compound, [Pd[Me-DUPHOS][MeCN]{sub 2}][BF{sub 4}]{sub 2}, [Me-DUPHOS: 1,2-bis[2,5-dimethylphospholano]benzene] is an effective catalyst for the highly enantioselective, alternating copolymerization of olefins, such as aliphatic {alpha}-olefins, with carbon monoxide to form optically active, isotactic polymers which can serve as excellent starting materials for the synthesis of other classes of chiral polymers. For example, the complete reduction of a propylene-carbon monoxide copolymer resulted in the formation of a novel, optically active poly[1,4-alcohol]. Also, the previously described catalyst is a catalyst for the novel alternating isomerization cooligomerization of 2-butene with carbon monoxide to form optically active, isotactic poly[1,5-ketone].
3. Characterization of Bonding Between Poly[dimethylsiloxane] and Cyclic Olefin Coplymer Using Corona Discharge Induced Grafting Polymerization PubMed Central Liu, Ke; Gu, Pan; Hamaker, Kiri; Fan, Z. Hugh 2011-01-01 Thermoplastics have been increasingly used for fabricating microfluidic devices because of their low cost, mechanical/biocompatible attributes, and well-established manufacturing processes. However, there is sometimes a need to integrate such a device with components made from other materials such as polydimethylsiloxane [PDMS]. Bonding thermoplastics with PDMS to produce hybrid devices is not straightforward. We have reported our method to modify the surface property of a cyclic olefin copolymer [COC] substrate by using corona discharge and grafting polymerization of 3-[trimethoxysilyl]propyl methacrylate; the modified surface enabled strong bonding of COC with PDMS. In this paper, we report our studies on the surface modification mechanism using attenuated total reflectance Fourier transform infrared spectroscopy [ATR-FTIR], X-ray photoelectron spectroscopy [XPS], atomic force microscopy [AFM] and contact angle measurement. Using this bonding method, we fabricated a three-layer [COC/PDMS/COC] hybrid device consisting of elastomer-based valve arrays. The microvalve operation was confirmed through the displacement of a dye solution in a fluidic channel when the elastomer membrane was pneumatically actuated. Valve-enabled microfluidic handling was demonstrated. PMID:21962541
4. Request for Symposia Support: Advances in Olefin Polymerization Catalysis DTIC Science & Technology 2014-11-24 States Polyolefins, including polyethylene [ HDPE and LLDPE] ad polypropylene [PP], represent half of commercial polymers produced in the world...i.e. HDPE vs. UHMWPE] by simply changing the catalyst. Despite this success, the development of novel transition metal olefin polymerization
5. Cyclic Polymers: From Scientific Curiosity to Advanced Materials for Gene Delivery and Surface Modification. PubMed Verbraeken, Bart; Hoogenboom, Richard 2017-06-12 Cyclic versus linear: The superiority of cyclic polymers over their linear counterparts is highlighted. Cyclic poly[2-oxazoline]s have been shown to provide excellent shielding properties when grafted to TiO 2 surfaces and Fe 3 O 4 nanoparticles owing to their ultrahigh grafting densities leading to low friction surfaces, superior antifouling properties, and extreme nanoparticle stabilization. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.
6. Copper[II] acetate promoted intramolecular diamination of unactivated olefins. PubMed Zabawa, Thomas P; Kasi, Dhanalakshmi; Chemler, Sherry R 2005-08-17 A concise method for the synthesis of cyclic sulfamides and vicinal diamines is presented. This method is enabled by Cu[OAc]2 and demonstrates a new transformation for this metal. Both five- and six-membered vicinal diamine-containing heterocycles have been synthesized in good to excellent yields, and substrate-based asymmetric induction has been achieved. This is the first reported example of intramolecular diamination of olefins.
7. Characterization of bonding between poly[dimethylsiloxane] and cyclic olefin copolymer using corona discharge induced grafting polymerization. PubMed Liu, Ke; Gu, Pan; Hamaker, Kiri; Fan, Z Hugh 2012-01-01 Thermoplastics have been increasingly used for fabricating microfluidic devices because of their low cost, mechanical/biocompatible attributes, and well-established manufacturing processes. However, there is sometimes a need to integrate such a device with components made from other materials such as polydimethylsiloxane [PDMS]. Bonding thermoplastics with PDMS to produce hybrid devices is not straightforward. We have reported our method to modify the surface property of a cyclic olefin copolymer [COC] substrate by using corona discharge and grafting polymerization of 3-[trimethoxysilyl]propyl methacrylate; the modified surface enabled strong bonding of COC with PDMS. In this paper, we report our studies on the surface modification mechanism using attenuated total reflectance Fourier transform infrared spectroscopy [ATR-FTIR], X-ray photoelectron spectroscopy [XPS], atomic force microscopy [AFM] and contact angle measurement. Using this bonding method, we fabricated a three-layer [COC/PDMS/COC] hybrid device consisting of elastomer-based valve arrays. The microvalve operation was confirmed through the displacement of a dye solution in a fluidic channel when the elastomer membrane was pneumatically actuated. Valve-enabled microfluidic handling was demonstrated. Copyright © 2011 Elsevier Inc. All rights reserved.
8. Artificial Informational Polymers and Nanomaterials from Ring-Opening Metathesis Polymerization NASA Astrophysics Data System [ADS] James, Carrie Rae Inspired by naturally occurring polymers [DNA, polypeptides, polysaccharides, etc.] that can self-assemble on the nanoscale into complex, information-rich architectures, we have synthesized nucleic acid based polymers using ROMP. These polymers were synthesized using a graft-through strategy, whereby nucleic acids bearing a strained cyclic olefin were directly polymerized. This is the first example of the graft-through polymerization of nucleic acids. Our approach takes advantage of non-charged peptide nucleic acids [PNAs] as elements to incorporate into ROMP polymer backbones. PNA is a synthetic nucleic acid analogue known for its increased affinity and specificity for complementary DNA or RNA. To accomplish the graft-through polymerization of PNA, we conjugated PNA to strained cyclic olefins using solid phase peptide conjugation chemistry. These PNA monomers were then directly polymerized into homo and block copolymers forming brushes, or comb-like arrangements, of information. Block copolymer amphiphiles of these materials, where the PNA brush served as the hydrophilic portion, were capable of self-assembly into spherical nanoparticles [PNA NPs]. These PNA NPs were then studied with respect to their ability to hybridize complementary DNA sequences, as well as their ability to undergo cellular internalization. PNA NPs consisting of densely packed brushes of nucleic acids possessed increased thermal stability when mixed with their complementary DNA sequence, indicating a greater DNA binding affinity over their unpolymerized PNA counterparts. In addition, by arranging the PNA into dense brushes at the surface of the nanoparticle, Cy5.5 labeled PNA NPs were able to undergo cellular internalization into HeLa cells without the need for an additional cellular delivery device. Importantly, cellular internalization of PNA has remained a significant challenge in the literature due to the neutrally charged amino-ethyl glycine backbone of PNA. Therefore, this represents a
9. Injection and injection-compression moulding replication capability for the production of polymer lab-on-a-chip with nano structures NASA Astrophysics Data System [ADS] Calaon, M.; Tosello, G.; Garnaes, J.; Hansen, H. N. 2017-10-01 The manufacturing precision and accuracy in the production of polymer lab-on-a-chip components with 100-130 nm deep nanochannels are evaluated using a metrological approach. Replication fidelity on corresponding process fingerprint test nanostructures over different substrates [nickel tool and polymer part] is quantified through traceable atomic force microscope measurements. Dimensions of injection moulded [IM] and injection-compression moulded [ICM] thermoplastic cyclic olefin copolymer nanofeatures are characterized depending on process parameters and four different features positions on a 30 × 80 mm2 area. Replication capability of IM and ICM technologies are quantified and the products tolerance at the nanometre dimensional scale verified.
10. Supramolecular polymer formation by cyclic dinucleotides and intercalators affects dinucleotide enzymatic processing PubMed Central Nakayama, Shizuka; Zhou, Jie; Zheng, Yue; Szmacinski, Henryk; Sintim, Herman O 2016-01-01 Background: Cyclic dinucleotides form supramolecular aggregates with intercalators, and this property could be utilized in nanotechnology and medicine. Methods & results: Atomic force microscopy and electrophoretic mobility shift assays were used to show that cyclic diguanylic acid [c-di-GMP] forms G-wires in the presence of intercalators. The average fluorescence lifetime of thiazole orange, when bound to c-di-GMP was greater than when bound to DNA G-quadruplexes or dsDNA. The stability of c-di-GMP supramolecular polymers is dependent on both the nature of the cation present and the intercalator. C-di-GMP or cyclic diadenylic acid/intercalator complexes are more resistant to cleavage by YybT, a phosphodiesterase, than the uncomplexed nucleotides. Conclusion: Cleavage of bacterial cyclic dinucleotides could be slowed down via complexation with small molecules and that this could be utilized for diverse applications in nanotechnology and medicine. PMID:28031943
11. Separation of Olefin/Paraffin Mixtures with Carrier Facilitated Membrane Final Report DOE Office of Scientific and Technical Information [OSTI.GOV] Merkel, T.C.; Blanc, R.; Zeid, J. 2007-03-12 successful effort to improve membrane coating solution stability resulted in the finding that membrane performance loss could be reversed for all poisoning cases except hydrogen sulfide exposure. This discovery offers the potential to extend membrane lifetime through cyclic regeneration. We also found that certain mixed carriers exhibited greater stability in reducing environments than exhibited by silver salt alone. These results offer promise that solutions to deal with carrier poisoning are possible. The main achievement of this program was the progress made in gaining a more complete understanding of the membrane stability challenges faced in the use of facilitated olefin transport membranes. Our systematic study of facilitated olefin transport uncovered the full extent of the stability challenge, including the first known identification of olefin conditioning and its impact on membrane development. We believe that significant additional fundamental research is required before facilitated olefin transport membranes are ready for industrial implementation. The best-case scenario for further development of this technology would be identification of a novel carrier that is intrinsically more stable than silver ions. If the stability problems could be largely circumvented by development of a new carrier, it would provide a clear breakthrough toward finally recognizing the potential of facilitated olefin transport. However, even if such a carrier is identified, additional development will be required to insure that the membrane matrix is a benign host for the olefin-carrier complexation reaction and shows good long-term stability.« less
12. A general microchip surface modification approach using a spin-coated polymer resist film doped with hydroxypropyl cellulose. PubMed Sun, Xiuhua; Yang, Weichun; Geng, Yanli; Woolley, Adam T 2009-04-07 We have developed a simple and effective method for surface modification of polymer microchips by entrapping hydroxypropyl cellulose [HPC] in a spin-coated thin film on the surface. Poly[methyl methacrylate-8.5-methacrylic acid], a widely available commercial resist formulation, was utilized as a matrix for dissolving HPC and providing adherence to native polymer surfaces. Various amounts of HPC [0.1-2.0%] dissolved in the copolymer and spun on polymer surfaces were evaluated. The modified surfaces were characterized by contact angle measurement, X-ray photoelectron spectroscopy and atomic force microscopy. The developed method was applied on both poly[methyl methacrylate] and cyclic olefin copolymer microchips. A fluorescently labeled myoglobin digest, binary protein mixture, and human serum sample were all separated in these surface-modified polymer microdevices. Our work exhibits an easy and reliable way to achieve favorable biomolecular separation performance in polymer microchips.
13. A general microchip surface modification approach using a spin-coated polymer resist film doped with hydroxypropyl cellulose PubMed Central Sun, Xiuhua; Yang, Weichun; Geng, Yanli; Woolley, Adam T. 2009-01-01 We have developed a simple and effective method for surface modification of polymer microchips by entrapping hydroxypropyl cellulose [HPC] in a spin-coated thin film on the surface. Poly[methyl methacrylate-8.5-methacrylic acid], a widely available commercial resist formulation, was utilized as a matrix for dissolving HPC and providing adherence to native polymer surfaces. Various amounts of HPC [0.1–2.0%] dissolved in the copolymer and spun on polymer surfaces were evaluated. The modified surfaces were characterized by contact angle measurement, X-ray photoelectron spectroscopy and atomic force microscopy. The developed method was applied on both poly[methyl methacrylate] and cyclic olefin copolymer microchips. A fluorescently labeled myoglobin digest, binary protein mixture, and human serum sample were all separated in these surface-modified polymer microdevices. Our work exhibits an easy and reliable way to achieve favorable biomolecular separation performance in polymer microchips. PMID:19294306
14. Shell Higher Olefins Process. ERIC Educational Resources Information Center Lutz, E. F. 1986-01-01 Shows how olefin isomerization and the exotic olefin metathesis reaction can be harnessed in industrial processes. Indicates that the Shell Higher Olefins Process makes use of organometallic catalysts to manufacture alpha-olefins and internal carbon-11 through carbon-14 alkenes in a flexible fashion that can be adjusted to market needs. [JN]
15. Photosensitized oxidation of unsaturated polymers NASA Technical Reports Server [NTRS] Golub, M. A. 1979-01-01 The photosensitized oxidation or singlet oxygenation of unsaturated hydrocarbon polymers and of their model compounds was reviewed. Emphasis was on cis and trans forms of 1,4-polyisoprene, 1,4-polybutadiene and 1,2-poly[1,4-hexadiene], and on 1,4-poly[2,3-dimethyl-1,3-butadiene]. The microstructural changes which occur in these polymers on reaction with O2-1 in solution were investigated by infrared H-1 and C-13 NMR spectroscopy. The polymers were shown to yield allylic hydroperoxides with shifted double bonds according to the ene mechanism established for simple olefins. The photosensitized oxidation of the above unsaturated polymer exhibited zero order kinetics, the relative rates paralleling the reactivities of the corresponding simple olefins towards O2-1.
16. Gel polymer electrolyte for lithium-ion batteries comprising cyclic carbonate moieties NASA Astrophysics Data System [ADS] Tillmann, S. D.; Isken, P.; Lex-Balducci, A. 2014-12-01 A polymer system based on oligo [ethylene glycol] methyl ether methacrylate [OEGMA] and cyclic carbonate methacrylate [CCMA] was chosen as matrix to realize high-performance gel polymer electrolytes due to the fact that both monomers are able to interact with the liquid electrolyte, thus, retaining it inside the matrix. Additionally, OEGMA enables high flexibility, while CCMA provides mechanical stability. The polymer displays a high thermal stability up to 200 °C and a glass transition temperature below room temperature [5 °C] allowing an easy handling of the obtained films. By immobilizing the liquid electrolyte 1 M LiPF6 in EC:DMC 1:1 w:w in the polymer host a gel polymer electrolyte with a high conductivity of 2.3 mS cm-1 at 25 °C and a stable cycling behavior with high capacities and efficiencies in Li[Ni1/3Co1/3Mn1/3]O2 [NCM]/graphite full cells is obtained. The investigated gel polymer electrolyte is identified as promising electrolyte for lithium-ion batteries, because it combines good electrochemical properties comparable to that of liquid electrolytes with the safety advantage that no leakage of the flammable electrolyte solvents can occur.
17. 21 CFR 177.1520 - Olefin polymers. Code of Federal Regulations, 2013 CFR 2013-04-01 ... HUMAN CONSUMPTION [CONTINUED] INDIRECT FOOD ADDITIVES: POLYMERS Substances for Use as Basic Components... [expressed as percent by weight of the polymer] in N-hexane at specified temperatures Maximum soluble fraction [expressed as percent by weight of polymer] in xylene at specified temperatures 1.1a...
18. 21 CFR 177.1520 - Olefin polymers. Code of Federal Regulations, 2012 CFR 2012-04-01 ... HUMAN CONSUMPTION [CONTINUED] INDIRECT FOOD ADDITIVES: POLYMERS Substances for Use as Basic Components... [expressed as percent by weight of the polymer] in N-hexane at specified temperatures Maximum soluble fraction [expressed as percent by weight of polymer] in xylene at specified temperatures 1.1a...
19. Ultra-broadband THz time-domain spectroscopy of common polymers using THz air photonics. PubMed D'Angelo, Francesco; Mics, Zoltán; Bonn, Mischa; Turchinovich, Dmitry 2014-05-19 Terahertz-range dielectric properties of the common polymers low-density polyethylene [LDPE], cyclic olefin/ethylene copolymer [TOPAS®], polyamide-6 [PA6], and polytetrafluoroethylene [PTFE or Teflon®] are characterized in the ultra-broadband frequency window 2-15 THz, using a THz time-domain spectrometer employing air-photonics for the generation and detection of single-cycle sub-50 fs THz transients. The time domain measurements provide direct access to both the absorption and refractive index spectra. The polymers LDPE and TOPAS® demonstrate negligible absorption and spectrally-flat refractive index across the entire spectroscopy window, revealing the high potential of these polymers for applications in THz photonics such as ultra-broadband polymer-based dielectric mirrors, waveguides, and fibers. Resonant high-frequency polar vibrational modes are observed and assigned in polymers PA6 and PTFE, and their dielectric functions in the complete frequency window 2-15 THz are theoretically reproduced. Our results demonstrate the potential of ultra-broadband air-photonics-based THz time domain spectroscopy as a valuable analytic tool for materials science.
20. Direct, enantioselective α-alkylation of aldehydes using simple olefins. PubMed Capacci, Andrew G; Malinowski, Justin T; McAlpine, Neil J; Kuhne, Jerome; MacMillan, David W C 2017-11-01 Although the α-alkylation of ketones has already been established, the analogous reaction using aldehyde substrates has proven surprisingly elusive. Despite the structural similarities between the two classes of compounds, the sensitivity and unique reactivity of the aldehyde functionality has typically required activated substrates or specialized additives. Here, we show that the synergistic merger of three catalytic processes-photoredox, enamine and hydrogen-atom transfer [HAT] catalysis-enables an enantioselective α-aldehyde alkylation reaction that employs simple olefins as coupling partners. Chiral imidazolidinones or prolinols, in combination with a thiophenol, iridium photoredox catalyst and visible light, have been successfully used in a triple catalytic process that is temporally sequenced to deliver a new hydrogen and electron-borrowing mechanism. This multicatalytic process enables both intra- and intermolecular aldehyde α-methylene coupling with olefins to construct both cyclic and acyclic products, respectively. With respect to atom and step-economy ideals, this stereoselective process allows the production of high-value molecules from feedstock chemicals in one step while consuming only photons.

1. Direct, enantioselective α-alkylation of aldehydes using simple olefins NASA Astrophysics Data System [ADS] Capacci, Andrew G.; Malinowski, Justin T.; McAlpine, Neil J.; Kuhne, Jerome; MacMillan, David W. C. 2017-11-01 Although the α-alkylation of ketones has already been established, the analogous reaction using aldehyde substrates has proven surprisingly elusive. Despite the structural similarities between the two classes of compounds, the sensitivity and unique reactivity of the aldehyde functionality has typically required activated substrates or specialized additives. Here, we show that the synergistic merger of three catalytic processes—photoredox, enamine and hydrogen-atom transfer [HAT] catalysis—enables an enantioselective α-aldehyde alkylation reaction that employs simple olefins as coupling partners. Chiral imidazolidinones or prolinols, in combination with a thiophenol, iridium photoredox catalyst and visible light, have been successfully used in a triple catalytic process that is temporally sequenced to deliver a new hydrogen and electron-borrowing mechanism. This multicatalytic process enables both intra- and intermolecular aldehyde α-methylene coupling with olefins to construct both cyclic and acyclic products, respectively. With respect to atom and step-economy ideals, this stereoselective process allows the production of high-value molecules from feedstock chemicals in one step while consuming only photons.
2. Pulsed laser deposition of plasmonic nanostructured gold on flexible transparent polymers at atmospheric pressure NASA Astrophysics Data System [ADS] McCann, Ronán; Hughes, Cian; Bagga, Komal; Stalcup, Apryll; Vázquez, Mercedes; Brabazon, Dermot 2017-06-01 In this paper, we outline a novel technique for the deposition of nanostructured thin films utilizing a modified form of pulsed laser deposition [PLD]. We demonstrate confined atmospheric PLD [CAP] for the deposition of gold on cyclic olefin polymer substrates. The deposition process is a simplified form of conventional PLD, with deposition conducted under atmospheric conditions and the substrate and target in close proximity. It was found that this confinement results in the deposition of nanostructured thin films on the substrate. Infrared spectroscopy showed no significant change of polymer surface chemistry as a result of the deposition process, and optical spectroscopy revealed plasmonic behavior of the resulting thin film. The effect of laser fluence on the deposition process was also examined with more uniform films deposited at higher fluences.
3. Effect of Cyclic Thermo-Mechanical Loads on Fatigue Reliability in Polymer Matrix Composites NASA Technical Reports Server [NTRS] Shah, A. R.; Murthy, P. L. N.; Chamis, C. C. 1996-01-01 A methodology to compute probabilistic fatigue life of polymer matrix laminated composites has been developed and demonstrated. Matrix degradation effects caused by long term environmental exposure and mechanical/thermal cyclic loads are accounted for in the simulation process. A unified time-temperature-stress dependent multi-factor interaction relationship developed at NASA Lewis Research Center has been used to model the degradation/aging of material properties due to cyclic loads. The fast probability integration method is used to compute probabilistic distribution of response. Sensitivities of fatigue life reliability to uncertainties in the primitive random variables [e.g., constituent properties, fiber volume ratio, void volume ratio, ply thickness, etc.] computed and their significance in the reliability- based design for maximum life is discussed. The effect of variation in the thermal cyclic loads on the fatigue reliability for a [0/+/- 45/90][sub s] graphite/epoxy laminate with a ply thickness of 0.127 mm, with respect to impending failure modes has been studied. The results show that, at low mechanical cyclic loads and low thermal cyclic amplitudes, fatigue life for 0.999 reliability is most sensitive to matrix compressive strength, matrix modulus, thermal expansion coefficient, and ply thickness. Whereas at high mechanical cyclic loads and high thermal cyclic amplitudes, fatigue life at 0.999 reliability is more sensitive to the shear strength of matrix, longitudinal fiber modulus, matrix modulus, and ply thickness.
4. Selecting and designing with the right thermoplastic polymer for your microfluidic chip: a close look into cyclo-olefin polymer NASA Astrophysics Data System [ADS] Nevitt, Mark 2013-03-01 Engineers who are developing microfluidic devices and bioMEMs for life science applications have many aspects to consider when selecting the proper base materials for constructing a device. While glass and polydimethylsiloxane [PDMS] are the staple materials for proof-of-concept and prototype chip fabrication, they are not a feasible solution for commercial production due to their slow, labor-intensive production rate. Alternatively, a molded or extruded thermoplastic solution can deliver the precision, consistency, and high volume capability required for commercial scale production. Traditional thermoplastics, such as polymethylmethacrylate [PMMA], polycarbonate [PC], and polystyrene [PS], are well known by development engineers in the bioscience community; however, cyclo-olefin polymer [COP], a relative newcomer in the world of plastics, is gaining increasing attention for use in microfluidic devices due to its unique balance of key properties compared to conventional thermoplastics. In this paper, we provide a comprehensive look at the properties which make COP an excellent candidate for providing the flow cell support and reagent storage functions in microfluidic assays. We also explore the processing attributes and capabilities of COP resin and film which are crucial for manufacturing high-performance microfluidic devices.
5. Direct, enantioselective α-alkylation of aldehydes using simple olefins PubMed Central Capacci, Andrew G.; Malinowski, Justin T.; McAlpine, Neil J.; Kuhne, Jerome; MacMillan, David W. C. 2017-01-01 Although the α-alkylation of ketones has already been established, the analogous reaction using aldehyde substrates has proven surprisingly elusive. Despite the structural similarities between the two classes of compounds, the sensitivity and unique reactivity of the aldehyde functionality has typically required activated substrates or specialized additives. Here, we show that the synergistic merger of three catalytic processes—photoredox, enamine and hydrogen-atom transfer [HAT] catalysis—enables an enantioselective α-aldehyde alkylation reaction that employs simple olefins as coupling partners. Chiral imidazolidinones or prolinols, in combination with a thiophenol, iridium photoredox catalyst and visible light, have been successfully used in a triple catalytic process that is temporally sequenced to deliver a new hydrogen and electron-borrowing mechanism. This multicatalytic process enables both intra- and intermolecular aldehyde α-methylene coupling with olefins to construct both cyclic and acyclic products, respectively. With respect to atom and step-economy ideals, this stereoselective process allows the production of high-value molecules from feedstock chemicals in one step while consuming only photons. PMID:29064486
6. Terminal Olefin Profiles and Phylogenetic Analyses of Olefin Synthases of Diverse Cyanobacterial Species. PubMed Zhu, Tao; Scalvenzi, Thibault; Sassoon, Nathalie; Lu, Xuefeng; Gugger, Muriel 2018-07-01 Cyanobacteria can synthesize alkanes and alkenes, which are considered to be infrastructure-compatible biofuels. In terms of physiological function, cyanobacterial hydrocarbons are thought to be essential for membrane flexibility for cell division, size, and growth. The genetic basis for the biosynthesis of terminal olefins [1-alkenes] is a modular type I polyketide synthase [PKS] termed olefin synthase [Ols]. The modular architectures of Ols and structural characteristics of alkenes have been investigated only in a few species of the small percentage [approximately 10%] of cyanobacteria that harbor putative Ols pathways. In this study, investigations of the domains, modular architectures, and phylogenies of Ols in 28 cyanobacterial strains suggested distinctive pathway evolution. Structural feature analyses revealed 1-alkenes with three carbon chain lengths [C 15 , C 17 , and C 19 ]. In addition, the total cellular fatty acid profile revealed the diversity of the carbon chain lengths, while the fatty acid feeding assay indicated substrate carbon chain length specificity of cyanobacterial Ols enzymes. Finally, in silico analyses suggested that the N terminus of the modular Ols enzyme exhibited characteristics typical of a fatty acyl-adenylate ligase [FAAL], suggesting a mechanism of fatty acid activation via the formation of acyl-adenylates. Our results shed new light on the diversity of cyanobacterial terminal olefins and a mechanism for substrate activation in the biosynthesis of these olefins. IMPORTANCE Cyanobacterial terminal olefins are hydrocarbons with promising applications as advanced biofuels. Despite the basic understanding of the genetic basis of olefin biosynthesis, the structural diversity and phylogeny of the key modular olefin synthase [Ols] have been poorly explored. An overview of the chemical structural traits of terminal olefins in cyanobacteria is provided in this study. In addition, we demonstrated by in vivo fatty acid feeding assays that
7. Micro pore arrays in free standing cyclic olefin copolymer membranes: fabrication and surface functionalization strategies for in-vitro barrier tissue models NASA Astrophysics Data System [ADS] Gel, M.; Kandasamy, S.; Cartledge, K.; Be, C. L.; Haylock, D. 2013-12-01 In recent years there has been growing interest in micro engineered in-vitro models of tissues and organs. These models are designed to mimic the in-vivo like physiological conditions with a goal to study human physiology in an organ-specific context or to develop in-vitro disease models. One of the challenges in the development of these models is the formation of barrier tissues in which the permeability is controlled locally by the tissues cultured at the interface. In-vitro models of barrier tissues are typically created by generating a monolayer of cells grown on thin porous membranes. This paper reports a robust preparation method for free standing porous cyclic olefin copolymer [COC] membranes. We also demonstrate that gelatin coated membranes facilitate formation of highly confluent monolayer of HUVECs. Membranes with thickness in the range of 2-3 um incorporating micro pores with diameter approximately 20 um were fabricated and integrated with microfluidic channels. The performance of the device was demonstrated with a model system mimicking the endothelial barrier in bone marrow sinusoids.
8. Understanding the desensitizing mechanism of olefin in explosives: shear slide of mixed HMX-olefin systems. PubMed Zhang, Chaoyang; Cao, Xia; Xiang, Bin 2012-04-01 We simulated the shear slide behavior of typical mixed HMX-olefin systems and the effect of thickness of olefin layers [4-22 Å] on the behavior at a molecular level by considering two cases: bulk shear and interfacial shear. The results show that: [1] the addition of olefin into HMX can reduce greatly the shear sliding barriers relative to the pure HMX in the two cases, suggesting that the desensitizing mechanism of olefin is controlled dominantly by its good lubricating property; [2] the change of interaction energy in both systoles of shear slide is strongly dominated by van der Waals interaction; and [3] the thickness of olefin layers in the mixed explosives can influence its desensitizing efficiency. That is, the excessive thinness of olefin layers in the mixed explosive systems, for example, several angstroms, can lead to very high sliding barriers.
9. 21 CFR 177.1520 - Olefin polymers. Code of Federal Regulations, 2011 CFR 2011-04-01 ... by reaction with fumaric acid in the absence of free radical initiators. Such polymers shall contain... acid in the absence of free radical initiators. Such polymers shall contain not more than 4.5 percent... tube for preheated, oxygen-free nitrogen, and an outlet tube located 1 inch off center. Nitrogen is fed...
10. 21 CFR 177.1520 - Olefin polymers. Code of Federal Regulations, 2010 CFR 2010-04-01 ... by reaction with fumaric acid in the absence of free radical initiators. Such polymers shall contain... acid in the absence of free radical initiators. Such polymers shall contain not more than 4.5 percent... tube for preheated, oxygen-free nitrogen, and an outlet tube located 1 inch off center. Nitrogen is fed...
11. Replication fidelity assessment of large area sub-μm structured polymer surfaces using scatterometry NASA Astrophysics Data System [ADS] Calaon, M.; Madsen, M. H.; Weirich, J.; Hansen, H. N.; Tosello, G.; Hansen, P. E.; Garnaes, J.; Tang, P. T. 2015-12-01 The present study addresses one of the key challenges in the product quality control of transparent structured polymer substrates, the replication fidelity of sub-μm structures over a large area. Additionally the work contributes to the development of new techniques focused on in-line characterization of large nanostructured surfaces using scatterometry. In particular an approach to quantify the replication fidelity of high volume manufacturing processes such as polymer injection moulding is presented. Both periodic channels and semi-spherical structures were fabricated on nickel shims used for later injection moulding of Cyclic-olefin-copolymer [COC] substrate were the sub-μm features where ultimately transferred. The scatterometry system was validated using calibrated atomic force microscopy measurements and a model based on scalar diffraction theory employed to calculate the expected angular distribution of the reflected and the transmitted intensity for the nickel surfaces and structured COC and, respectively.
12. Polymer composites containing nanotubes NASA Technical Reports Server [NTRS] Bley, Richard A. [Inventor] 2008-01-01 The present invention relates to polymer composite materials containing carbon nanotubes, particularly to those containing singled-walled nanotubes. The invention provides a polymer composite comprising one or more base polymers, one or more functionalized m-phenylenevinylene-2,5-disubstituted-p-phenylenevinylene polymers and carbon nanotubes. The invention also relates to functionalized m-phenylenevinylene-2,5-disubstituted-p-phenylenevinylene polymers, particularly to m-phenylenevinylene-2,5-disubstituted-p-phenylenevinylene polymers having side chain functionalization, and more particularly to m-phenylenevinylene-2,5-disubstituted-p-phenylenevinylene polymers having olefin side chains and alkyl epoxy side chains. The invention further relates to methods of making polymer composites comprising carbon nanotubes.
13. Multinuclear group 4 catalysis: olefin polymerization pathways modified by strong metal-metal cooperative effects. PubMed McInnis, Jennifer P; Delferro, Massimiliano; Marks, Tobin J 2014-08-19 Polyolefins are produced today catalytically on a vast scale, and the manufactured polymers find use in everything from artificial limbs and food/medical packaging to automotive and electrical components and lubricants. Although polyolefin monomers are typically cheap [e.g., ethylene, propylene, α-olefins], the resulting polymer properties can be dramatically tuned by the particular polymerization catalyst employed, and reflect a rich interplay of macromolecular chemistry, materials science, and physics. For example, linear low-density polyethylene [LLDPE], produced by copolymerization of ethylene with linear α-olefin comonomers such as 1-butene, 1-hexene, or 1-octene, has small but significant levels of short alkyl branches [C2, C4, C6] along the polyethylene backbone, and is an important technology material due to outstanding rheological and mechanical properties. In 2013, the total world polyolefin production was approximately 211 million metric tons, of which about 11% was LLDPE. Historically, polyolefins were produced using ill-defined but highly active heterogeneous catalysts composed of supported groups 4 or 6 species [usually halides] activated by aluminum alkyls. In 1963, Karl Ziegler and Giulio Natta received the Nobel Prize for these discoveries. Beginning in the late 1980s, a new generation of group 4 molecule-based homogeneous olefin polymerization catalysts emerged from discoveries by Walter Kaminsky, a team led by James Stevens at The Dow Chemical Company, this Laboratory at Northwestern University, and a host of talented groups in Germany, Italy, Japan, the United Kingdom, and the United States. These new "single-site" catalysts and their activating cocatalysts were far better defined and more rationally tunable in terms of structure, mechanism, thermodynamics, and catalyst activity and selectivity than ever before possible. An explosion of research advances led to new catalysts, cocatalysts, deeper mechanistic understanding of both the
14. Metathesis process for preparing an alpha, omega-functionalized olefin DOEpatents Burdett, Kenneth A.; Mokhtarzadeh, Morteza; Timmers, Francis J. 2010-10-12 A cross-metathesis process for preparing an .alpha.,.omega.-functionalized olefin, such as methyl 9-decenoate, and an .alpha.-olefin having three or more carbon atoms, such as 1-decene. The process involves contacting in a first reaction zone an .alpha.-functionalized internal olefin, such as methyl oleate, and an .alpha.-olefinic monomer having three or more carbon atoms, such as 1-decene, with a first metathesis catalyst to prepare an effluent stream containing the .alpha.,.omega.-functionalized olefin, such as methyl 9-decenoate, an unfunctionalized internal olefin, such as 9-octadecene, unconverted reactant olefins, and optionally, an .alpha.,.omega.-difunctionalized internal olefinic dimer, such as dimethyl 9-octadecen-1,18-dioate; separating said effluent streams; then contacting in a second reaction zone the unfunctionalized internal olefin with ethylene in the presence of a second metathesis catalyst to obtain a second product effluent containing the .alpha.-olefinic monomer having three or more carbon atoms; and cycling a portion of the .alpha.-olefinic monomer stream[s] to the first zone.
15. Myoglobin-Catalyzed Olefination of Aldehydes. PubMed Tyagi, Vikas; Fasan, Rudi 2016-02-12 The olefination of aldehydes constitutes a most valuable and widely adopted strategy for constructing carbon-carbon double bonds in organic chemistry. While various synthetic methods have been made available for this purpose, no biocatalysts are known to mediate this transformation. Reported herein is that engineered myoglobin variants can catalyze the olefination of aldehydes in the presence of α-diazoesters with high catalytic efficiency [up to 4,900 turnovers] and excellent E diastereoselectivity [92-99.9 % de]. This transformation could be applied to the olefination of a variety of substituted benzaldehydes and heteroaromatic aldehydes, also in combination with different alkyl α-diazoacetate reagents. This work provides a first example of biocatalytic aldehyde olefination and extends the spectrum of synthetically valuable chemical transformations accessible using metalloprotein-based catalysts. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
16. Olefinic Thermoplastic Elastomer Gels: Combining Polymer Crystallization and Microphase Separation in a Selective Solvent DOE Office of Scientific and Technical Information [OSTI.GOV] Armstrong, Daniel P.; Mineart, Kenneth P.; Lee, Byeongdu Since selectively swollen thermoplastic elastomer gels [TPEGs] afford a wide range of beneficial properties that open new doors to developing elastomer-based technologies, in this study we examine the unique structure-property behavior of TPEGs composed of olefinic block copolymers [OBCs]. Unlike their styrenic counterparts typically possessing two chemically different blocks, this class of multiblock copolymers consists of linear polyethylene hard blocks and poly[ethylene-co-α-octene] soft blocks, in which case, microphase separation between the hard and the soft blocks is accompanied by crystallization of the hard blocks. We prepare olefinic TPEGs [OTPEGs] through the incorporation of a primarily aliphatic oil that selectively swellsmore » the soft block and investigate the resultant morphological features through the use of polarized light microscopy and small-/wideangle X-ray scattering. These features are correlated with thermal and mechanical property measurements from calorimetry, rheology, and extensiometry to elucidate the roles of crystallization and self-assembly on gel characteristics and establish useful structure-property relationships.« less
17. Olefinic Thermoplastic Elastomer Gels: Combining Polymer Crystallization and Microphase Separation in a Selective Solvent DOE PAGES Armstrong, Daniel P.; Mineart, Kenneth P.; Lee, Byeongdu; ... 2016-11-01 Since selectively swollen thermoplastic elastomer gels [TPEGs] afford a wide range of beneficial properties that open new doors to developing elastomer-based technologies, in this study we examine the unique structure-property behavior of TPEGs composed of olefinic block copolymers [OBCs]. Unlike their styrenic counterparts typically possessing two chemically different blocks, this class of multiblock copolymers consists of linear polyethylene hard blocks and poly[ethylene-co-α-octene] soft blocks, in which case, microphase separation between the hard and the soft blocks is accompanied by crystallization of the hard blocks. We prepare olefinic TPEGs [OTPEGs] through the incorporation of a primarily aliphatic oil that selectively swellsmore » the soft block and investigate the resultant morphological features through the use of polarized light microscopy and small-/wideangle X-ray scattering. These features are correlated with thermal and mechanical property measurements from calorimetry, rheology, and extensiometry to elucidate the roles of crystallization and self-assembly on gel characteristics and establish useful structure-property relationships.« less
18. Electrochromatography on acrylate-based monolith in cyclic olefin copolymer microchip: a cost-effective and easy-to-use technology. PubMed Ladner, Yoann; Crétier, Gérard; Faure, Karine 2012-10-01 This article shows that there is great interest in using an electrochromatographic microchip made of hexyl acrylate [HA] based porous monolith cast within the channel of a cyclic olefin copolymer [COC] device. The monolith is simultaneously in situ synthesized and anchored to the inner walls of the channel in less than 10 min. By appropriate choice of light intensity used during the synthesis, the separation efficiency obtained for nonpolar solutes such as polycyclic aromatic hydrocarbons [PAH] is increased up to 250 000 plates/m. The performance of this HA-filled COC microchip was investigated for a wide range of analytes of varying nature. The reversed-phase separation of four aflatoxins is obtained in less than 2 min. The baseline separation of a mixture of neurotransmitters including six amino acids and two catecholamines is possible thanks to the superimposition of the differences in electrophoretic mobility on the chromatographic process. The durability of the system at pH 13 allows the separation of five biogenic amines and the quantitative determination of two of them in numerous wine samples. The feasibility of on-line preconcentration is also demonstrated. Hydrophilic surface modification of COC channel via UV-photografting with poly[ethylene glycol] methacrylate [PEGMA] before in situ synthesis of HA, is necessary to reduce the adsorption of very hydrophobic solutes such as PAH during enrichment. The detection limit of fluoranthene is decreased down to less than 1 ppb with a preconcentration of 4.5 h on the HA-filled PEGMA functionalized COC microchip. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
19. Characterization of activated cyclic olefin copolymer: effects of ethylene/norbornene content on the physiochemical properties. PubMed O'Neil, Colleen E; Taylor, Scott; Ratnayake, Kumuditha; Pullagurla, Swathi; Singh, Varshni; Soper, Steven A 2016-11-28 The ethylene/norbornene content within cyclic olefin copolymer [COC] is well known to affect the chemical and physical properties of the copolymer, such as the glass transition temperature [T g ] and transparency. However, no work has been reported evaluating the effects of the ethylene/norbornene content on the surface properties of COC following UV/O 3 or O 2 plasma activation. Activation with either O 2 plasma or UV/O 3 is often used to assist in thermal assembly of fluidic devices, increasing the wettability of the surfaces, or generating functional scaffolds for the attachment of biological elements. Thus, we investigated differences in the physiochemical surface properties of various ethylene/norbornene compositions of COC following activation using analytical techniques such as water contact angle [WCA], ATR-FTIR, XPS, TOF-SIMS, UV-VIS, AFM and a colorimetric assay utilizing Toluidine Blue O [TBO]. Results showed that increased norbornene content led to the generation of more oxygen containing functionalities such as alcohols, ketones, aldehydes and carboxyl groups when activated with either UV/O 3 or O 2 plasma. Specifically, COC with ∼60% norbornene content showed a significantly higher -COOH functional group density when compared to COC with a 50% norbornene content and COC with a 35% norbornene content following UV/O 3 or O 2 plasma activation. Furthermore, COC with large norbornene contents showed a smaller average RMS roughness [0.65 nm] when compared to COC containing low norbornene contents [0.95 nm] following activation making this substrate especially suited for nanofluidic applications, which require smooth surfaces to minimize effects arising from dielectrophoretic trapping or non-specific adsorption. Although all COC substrates showed >90% transparency at wavelengths >475 nm, COC possessing high norbornene contents showed significantly less transparency at wavelengths below 475 nm following activation, making optical detection in this region
20. Producing alpha-olefins using polyketide synthases DOE Office of Scientific and Technical Information [OSTI.GOV] Fortman, Jeffrey L.; Katz, Leonard; Steen, Eric J. 2018-01-02 The present invention provides for a polyketide synthase [PKS] capable of synthesizing an .alpha.-olefin, such as 1-hexene or butadiene. The present invention also provides for a host cell comprising the PKS and when cultured produces the .alpha.-olefin.

1. Microscale patterning of thermoplastic polymer surfaces by selective solvent swelling. PubMed Rahmanian, Omid; Chen, Chien-Fu; DeVoe, Don L 2012-09-04 A new method for the fabrication of microscale features in thermoplastic substrates is presented. Unlike traditional thermoplastic microfabrication techniques, in which bulk polymer is displaced from the substrate by machining or embossing, a unique process termed orogenic microfabrication has been developed in which selected regions of a thermoplastic surface are raised from the substrate by an irreversible solvent swelling mechanism. The orogenic technique allows thermoplastic surfaces to be patterned using a variety of masking methods, resulting in three-dimensional features that would be difficult to achieve through traditional microfabrication methods. Using cyclic olefin copolymer as a model thermoplastic material, several variations of this process are described to realize growth heights ranging from several nanometers to tens of micrometers, with patterning techniques include direct photoresist masking, patterned UV/ozone surface passivation, elastomeric stamping, and noncontact spotting. Orogenic microfabrication is also demonstrated by direct inkjet printing as a facile photolithography-free masking method for rapid desktop thermoplastic microfabrication.
2. Microscale Patterning of Thermoplastic Polymer Surfaces by Selective Solvent Swelling PubMed Central Rahmanian, Omid; Chen, Chien-Fu; DeVoe, Don L. 2012-01-01 A new method for the fabrication of microscale features in thermoplastic substrates is presented. Unlike traditional thermoplastic microfabrication techniques, in which bulk polymer is displaced from the substrate by machining or embossing, a unique process termed orogenic microfabrication has been developed in which selected regions of a thermoplastic surface are raised from the substrate by an irreversible solvent swelling mechanism. The orogenic technique allows thermoplastic surfaces to be patterned using a variety of masking methods, resulting in three-dimensional features that would be difficult to achieve through traditional microfabrication methods. Using cyclic olefin copolymer as a model thermoplastic material, several variations of this process are described to realize growth heights ranging from several nanometers to tens of microns, with patterning techniques include direct photoresist masking, patterned UV/ozone surface passivation, elastomeric stamping, and noncontact spotting. Orogenic microfabrication is also demonstrated by direct inkjet printing as a facile photolithography-free masking method for rapid desktop thermoplastic microfabrication. PMID:22900539
3. Spectroscopic Evidence of Anthropogenic Compounds Extraction from Polymers by Fluorescent Dissolved Organic Matter in Natural Water NASA Astrophysics Data System [ADS] Miranda, M.; Trojzuck, A.; Voss, D.; Gassmann, S.; Zielinski, O. 2016-04-01 FDOM is one of the most important carriers of anthropogenic compounds in natural waters. It can combine with environmental contaminants and polymers to form diverse chemical structures. To this end, here a microfluidic chip was designed for the analysis of these changes in fluorescent dissolved organic matter [FDOM] fingerprints due to thermal treatment and varying time intervals of exposure. Excitation Emission Matrix Spectroscopy [EEMS] approach was utilized to detect and identify the inherent compounds in sampled FDOM. Strong direct correlations were founded, Spearman rank correlation values [ρ = 0.85 at α = 0.1, n = 4] and linear correlation R2 = 0.8359 were noted between thermal treatment pattern 2 and fluorescence intensity of samples. Materials, acrylic based glue and cyclic olefin copolymer [COC] polymer, used to design the microfluidic sensor were determined to possess unique spectral features in the ultraviolet to green spectrum using EEMS. The study therefore provides an insight on methods to identify contaminants in natural waters. This underlines the potential of optical sensors providing measurements at fast intervals, enabling environmental monitoring.
4. Recovery of olefin monomers DOEpatents Golden, Timothy Christoph; Weist, Jr., Edward Landis; Johnson, Charles Henry 2004-03-16 In a process for the production of a polyolefin, an olefin monomer is polymerised said polyolefin and residual monomer is recovered. A gas stream comprising the monomer and nitrogen is subjected to a PSA process in which said monomer is adsorbed on a periodically regenerated silica gel or alumina adsorbent to recover a purified gas stream containing said olefin and a nitrogen rich stream containing no less than 99% nitrogen and containing no less than 50% of the nitrogen content of the gas feed to the PSA process.
5. Low Leachable Container System Consisting of a Polymer-Based Syringe with Chlorinated Isoprene Isobutene Rubber Plunger Stopper. PubMed Kiminami, Hideaki; Takeuchi, Katsuyuki; Nakamura, Koji; Abe, Yoshihiko; Lauwers, Philippe; Dierick, William; Yoshino, Keisuke; Suzuki, Shigeru 2015-01-01 A 36 month leachable study on water for injection in direct contact within a polymer-based prefillable syringe consisting of a cyclo olefin polymer barrel, a chlorinated isoprene isobutene rubber plunger stopper, a polymer label attached on the barrel, and a secondary packaging was conducted at 25 ± 2 °C and 60 ± 5% relative humidity. Through the various comparison studies, no difference in the leachable amounts was observed between this polymer-based prefilled syringe and a glass bottle as a blank sample reference by 36 months. No influence on the leachables study outcome was noted from the printed label and/or label adhesive or from the secondary packaging. In an additional study, no acrylic acid used as the label adhesive leachable was detected by an extended storage for 45 months at 25 ± 2 °C and 60 ± 5% relative humidity as a worst case. To obtain more details, a comparison extractable study was conducted between a cyclo olefin polymer barrel and a glass barrel. In addition, chlorinated isoprene isobutene rubber and bromo isoprene isobutene rubber were compared. As a result, no remarkable difference was found in the organic extractables for syringe barrels. On the other hand, in the case of element extractable analysis, the values for the cyclo olefin polymer barrel were lower than that for the glass barrel. For the plunger stoppers, the chlorinated isoprene isobutene rubber applied in this study was showing a lower extractable profile as compared to the bromo isoprene isobutene rubber, both for organic and element extractables. In conclusion, the proposed polymer-based prefillable syringe system has great potential and represents a novel alternative that can achieve very low level extractable profiles and can bring additional value to the highly sensitive biotech drug market. A 36 month leachable study on water for injection in direct contact within a cyclo olefin polymer barrel and chlorinated isoprene isobutene rubber plunger stopper that has a
6. Fe-Catalyzed C–C Bond Construction from Olefins via Radicals PubMed Central 2017-01-01 This Article details the development of the iron-catalyzed conversion of olefins to radicals and their subsequent use in the construction of C–C bonds. Optimization of a reductive diene cyclization led to the development of an intermolecular cross-coupling of electronically-differentiated donor and acceptor olefins. Although the substitution on the donor olefins was initially limited to alkyl and aryl groups, additional efforts culminated in the expansion of the scope of the substitution to various heteroatom-based functionalities, providing a unified olefin reactivity. A vinyl sulfone acceptor olefin was developed, which allowed for the efficient synthesis of sulfone adducts that could be used as branch points for further diversification. Moreover, this reactivity was extended into an olefin-based Minisci reaction to functionalize heterocyclic scaffolds. Finally, mechanistic studies resulted in a more thorough understanding of the reaction, giving rise to the development of a more efficient second-generation set of olefin cross-coupling conditions. PMID:28094980
7. A new and selective cycle for dehydrogenation of linear and cyclic alkanes under mild conditions using a base metal NASA Astrophysics Data System [ADS] Solowey, Douglas P.; Mane, Manoj V.; Kurogi, Takashi; Carroll, Patrick J.; Manor, Brian C.; Baik, Mu-Hyun; Mindiola, Daniel J. 2017-11-01 Selectively converting linear alkanes to α-olefins under mild conditions is a highly desirable transformation given the abundance of alkanes as well as the use of olefins as building blocks in the chemical community. Until now, this reaction has been primarily the remit of noble-metal catalysts, despite extensive work showing that base-metal alkylidenes can mediate the reaction in a stoichiometric fashion. Here, we show how the presence of a hydrogen acceptor, such as the phosphorus ylide, when combined with the alkylidene complex [PNP]Ti=CHtBu[CH3] [PNP=N[2-P[CHMe2]2-4-methylphenyl]2-], catalyses the dehydrogenation of cycloalkanes to cyclic alkenes, and linear alkanes with chain lengths of C4 to C8 to terminal olefins under mild conditions. This Article represents the first example of a homogeneous and selective alkane dehydrogenation reaction using a base-metal titanium catalyst. We also propose a unique mechanism for the transfer dehydrogenation of hydrocarbons to olefins and discuss a complete cycle based on a combined experimental and computational study.
8. A new and selective cycle for dehydrogenation of linear and cyclic alkanes under mild conditions using a base metal. PubMed Solowey, Douglas P; Mane, Manoj V; Kurogi, Takashi; Carroll, Patrick J; Manor, Brian C; Baik, Mu-Hyun; Mindiola, Daniel J 2017-11-01 Selectively converting linear alkanes to α-olefins under mild conditions is a highly desirable transformation given the abundance of alkanes as well as the use of olefins as building blocks in the chemical community. Until now, this reaction has been primarily the remit of noble-metal catalysts, despite extensive work showing that base-metal alkylidenes can mediate the reaction in a stoichiometric fashion. Here, we show how the presence of a hydrogen acceptor, such as the phosphorus ylide, when combined with the alkylidene complex [PNP]Ti=CH t Bu[CH 3 ] [PNP=N[2-P[CHMe 2 ] 2 -4-methylphenyl] 2 - ], catalyses the dehydrogenation of cycloalkanes to cyclic alkenes, and linear alkanes with chain lengths of C 4 to C 8 to terminal olefins under mild conditions. This Article represents the first example of a homogeneous and selective alkane dehydrogenation reaction using a base-metal titanium catalyst. We also propose a unique mechanism for the transfer dehydrogenation of hydrocarbons to olefins and discuss a complete cycle based on a combined experimental and computational study.
9. Cyclic alkyl amino carbene [CAAC] ruthenium complexes as remarkably active catalysts for ethenolysis DOE PAGES Marx, Vanessa M.; Sullivan, Alexandra H.; Melaimi, Mohand; ... 2014-12-17 In this paper, an expanded family of ruthenium-based metathesis catalysts bearing cyclic alkyl amino carbene [CAAC] ligands was prepared. These catalysts exhibited exceptional activity in the ethenolysis of the seed-oil derivative methyl oleate. In many cases, catalyst turnover numbers [TONs] of more than 100,000 were achieved, at a catalyst loading of only 3 ppm. Remarkably, the most active catalyst system was able to achieve a TON of 340 000, at a catalyst loading of only 1 ppm. Finally, this is the first time a series of metathesis catalysts has exhibited such high performance in cross-metathesis reactions employing ethylene gas, withmore » activities sufficient to render ethenolysis applicable to the industrial-scale production of linear α-olefins [LAOs] and other terminal-olefin products.« less
10. Enhanced performance of a structured cyclo olefin copolymer-based amorphous silicon solar cell NASA Astrophysics Data System [ADS] Zhan, Xinghua; Chen, Fei; Gao, Mengyu; Tie, Shengnian; Gao, Wei 2017-07-01 The submicron array was fabricated onto a cyclo olefin copolymer [COC] film by a hot embossing method. An amorphous silicon p-i-n junction and transparent conductive layers were then deposited onto it through a plasma enhanced chemical vapor deposition [PECVD] and magnetron sputtering. The efficiency of the fabricated COC-based solar cell was measured and the result demonstrated 18.6% increase of the solar cell efficiency when compared to the sample without array structure. The imprinted polymer solar cells with submicron array indeed increase their efficiency.
11. 40 CFR 721.5425 - α-Olefin sulfonate, potassium salts. Code of Federal Regulations, 2014 CFR 2014-07-01 ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false α-Olefin sulfonate, potassium salts... Substances § 721.5425 α-Olefin sulfonate, potassium salts. [a] Chemical substance and significant new uses subject to reporting. [1] The chemical substance identified as an α-olefin sulfonate, potassium salt [PMN...
12. 40 CFR 721.5425 - α-Olefin sulfonate, potassium salts. Code of Federal Regulations, 2012 CFR 2012-07-01 ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false α-Olefin sulfonate, potassium salts... Substances § 721.5425 α-Olefin sulfonate, potassium salts. [a] Chemical substance and significant new uses subject to reporting. [1] The chemical substance identified as an α-olefin sulfonate, potassium salt [PMN...
13. 40 CFR 721.5425 - α-Olefin sulfonate, potassium salts. Code of Federal Regulations, 2013 CFR 2013-07-01 ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false α-Olefin sulfonate, potassium salts... Substances § 721.5425 α-Olefin sulfonate, potassium salts. [a] Chemical substance and significant new uses subject to reporting. [1] The chemical substance identified as an α-olefin sulfonate, potassium salt [PMN...
14. 40 CFR 721.5450 - α-Olefin sulfonate, sodium salt. Code of Federal Regulations, 2011 CFR 2011-07-01 ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false α-Olefin sulfonate, sodium salt. 721... Substances § 721.5450 α-Olefin sulfonate, sodium salt. [a] Chemical substance and significant new uses subject to reporting. [1] The chemical substance identified generically as α-olefin sulfonate, sodium salt...
15. 40 CFR 721.5425 - α-Olefin sulfonate, potassium salts. Code of Federal Regulations, 2010 CFR 2010-07-01 ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false α-Olefin sulfonate, potassium salts... Substances § 721.5425 α-Olefin sulfonate, potassium salts. [a] Chemical substance and significant new uses subject to reporting. [1] The chemical substance identified as an α-olefin sulfonate, potassium salt [PMN...
16. 40 CFR 721.5425 - α-Olefin sulfonate, potassium salts. Code of Federal Regulations, 2011 CFR 2011-07-01 ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false α-Olefin sulfonate, potassium salts... Substances § 721.5425 α-Olefin sulfonate, potassium salts. [a] Chemical substance and significant new uses subject to reporting. [1] The chemical substance identified as an α-olefin sulfonate, potassium salt [PMN...
17. Activation of olefins via asymmetric Bronsted acid catalysis DOE PAGES Tsuji, Nobuya; Kennemur, Jennifer L.; Buyck, Thomas; ... 2018-03-30 The activation of olefins for asymmetric chemical synthesis traditionally relies on transition metal catalysts. In contrast, biological enzymes with Bronsted acidic sites of appropriate strength can protonate olefins and thereby generate carbocations that ultimately react to form natural products. Although chemists have recently designed chiral Bronsted acid catalysts to activate imines and carbonyl compounds, mimicking these enzymes to protonate simple olefins that then engage in asymmetric catalytic reactions has remained a substantial synthetic challenge. Here, we show that a class of confined and strong chiral Bronsted acids enables the catalytic asymmetric intramolecular hydroalkoxylation of unbiased olefins. In conclusion, the methodologymore » gives rapid access to biologically active 1,1-disubstituted tetrahydrofurans, including [–]-Boivinianin A.« less
18. Activation of olefins via asymmetric Bronsted acid catalysis DOE Office of Scientific and Technical Information [OSTI.GOV] Tsuji, Nobuya; Kennemur, Jennifer L.; Buyck, Thomas The activation of olefins for asymmetric chemical synthesis traditionally relies on transition metal catalysts. In contrast, biological enzymes with Bronsted acidic sites of appropriate strength can protonate olefins and thereby generate carbocations that ultimately react to form natural products. Although chemists have recently designed chiral Bronsted acid catalysts to activate imines and carbonyl compounds, mimicking these enzymes to protonate simple olefins that then engage in asymmetric catalytic reactions has remained a substantial synthetic challenge. Here, we show that a class of confined and strong chiral Bronsted acids enables the catalytic asymmetric intramolecular hydroalkoxylation of unbiased olefins. In conclusion, the methodologymore » gives rapid access to biologically active 1,1-disubstituted tetrahydrofurans, including [–]-Boivinianin A.« less
19. Improving olefin tolerance and production in E. coli using native and evolved AcrB DOE PAGES Mingardon, Florence; Clement, Camille; Hirano, Kathleen; ... 2015-01-20 Microorganisms can be engineered for the production of chemicals utilized in the polymer industry. However many such target compounds inhibit microbial growth and might correspondingly limit production levels. Here, we focus on compounds that are precursors to bioplastics, specifically styrene and representative alpha-olefins; 1-hexene, 1-octene, and 1-nonene. We evaluated the role of the Escherichia coli efflux pump, AcrAB-TolC, in enhancing tolerance towards these olefin compounds. AcrAB-TolC is involved in the tolerance towards all four compounds in E. coli. Both styrene and 1-hexene are highly toxic to E. coli. Styrene is a model plastics precursor with an established route for productionmore » in E. coli [McKenna and Nielsen, 2011]. Though our data indicates that AcrAB-TolC is important for its optimal production, we observed a strong negative selection against the production of styrene in E. coli. Thus we used 1-hexene as a model compound to implement a directed evolution strategy to further improve the tolerance phenotype towards this alpha-olefin. We focused on optimization of AcrB, the inner membrane domain known to be responsible for substrate binding, and found several mutations [A279T, Q584R, F617L, L822P, F927S, and F1033Y] that resulted in improved tolerance. Several of these mutations could also be combined in a synergistic manner. Our study shows efflux pumps to be an important mechanism in host engineering for olefins, and one that can be further improved using strategies such as directed evolution, to increase tolerance and potentially production.« less
20. Nuclear alkylated pyridine aldehyde polymers and conductive compositions thereof NASA Technical Reports Server [NTRS] Rembaum, A.; Singer, S. [Inventor] 1970-01-01 A thermally stable, relatively conductive polymer was disclosed. The polymer was synthesized by condensing in the presence of catalyst a 2, 4, or 6 nuclear alklylated 2, 3, or 4 pyridine aldehyde or quaternary derivatives thereof to form a polymer. The pyridine groups were liked by olefinic groups between 2-4, 2-6, 2-3, 3-4, 3-6 or 4-6 positions. Conductive compositions were prepared by dissolving the quaternary polymer and an organic charge transfer complexing agent such as TCNQ in a mutual solvent such as methanol.

1. Cyclic Peptide-Polymer Nanotubes as Efficient and Highly Potent Drug Delivery Systems for Organometallic Anticancer Complexes. PubMed Larnaudie, Sophie C; Brendel, Johannes C; Romero-Canelón, Isolda; Sanchez-Cano, Carlos; Catrouillet, Sylvain; Sanchis, Joaquin; Coverdale, James P C; Song, Ji-Inn; Habtemariam, Abraha; Sadler, Peter J; Jolliffe, Katrina A; Perrier, Sébastien 2018-01-08 Functional drug carrier systems have potential for increasing solubility and potency of drugs while reducing side effects. Complex polymeric materials, particularly anisotropic structures, are especially attractive due to their long circulation times. Here, we have conjugated cyclic peptides to the biocompatible polymer poly[2-hydroxypropyl methacrylamide] [pHPMA]. The resulting conjugates were functionalized with organoiridium anticancer complexes. Small angle neutron scattering and static light scattering confirmed their self-assembly and elongated cylindrical shape. Drug-loaded nanotubes exhibited more potent antiproliferative activity toward human cancer cells than either free drug or the drug-loaded polymers, while the nanotubes themselves were nontoxic. Cellular accumulation studies revealed that the increased potency of the conjugate appears to be related to a more efficient mode of action rather than a higher cellular accumulation of iridium.
2. Stability of 10 mg/mL cefuroxime solution for intracameral injection in commonly used polypropylene syringes and new ready-to-use cyclic olefin copolymer sterile vials using the LC-UV stability-indicating method. PubMed Feutry, Frédéric; Simon, Nicolas; Genay, Stéphanie; Lannoy, Damien; Barthélémy, Christine; Décaudin, Bertrand; Labalette, Pierre; Odou, Pascal 2016-01-01 Injecting intracameral cefuroxime has been found beneficial in reducing the risk of postoperative endophthalmitis but its use has been limited through a lack of approved marketing and of ready-to-use single-units as well as the problem of aseptic compounding. Our aim was to assess a new automated primary packaging system which should ensure a higher level of sterility, thanks to its closed, sterile, ready-to-use polymer vial called "Crystal® vial". The chemical stability of a 10 mg/mL cefuroxime solution was compared in 1 mL Crystal® vials and 1 mL Luer-lock polypropylene syringes [actual reference] to eliminate any potential and specific interactions with its cyclic olefin copolymer [COC] body and elastomer stopper. Cefuroxime solution was introduced into vials and syringes and stored at -20 °C, +5 °C and +25°C/60% Relative Humidity. Cefuroxime concentration and the relative amount of the main degradation product [descarbamoyl-cefuroxime] were both determined by an HPLC/UV method indicating stability. Solutions were considered steady if the concentration remained at over 90% of the initial value. In the adapted storage conditions, the evolution of osmolality, pH and sterility was assessed. Stability profiles were identical between vials and syringes in all storage and temperature conditions. The solution was stable [cefuroxime concentration, pH and osmolality] and still sterile for 365 days at -20°C. The concentration fell below 90% after 21 days at +5 °C and after 16 h at +25°C/60%s relative humidity. The COC and thermoplastic elastomer of the vials had no impact on the degradation process confirming its possible use for a ready-to-use cefuroxime solution single-unit dose.
3. Ethenolysis: A Green Catalytic Tool to Cleave Carbon-Carbon Double Bonds. PubMed Bidange, Johan; Fischmeister, Cédric; Bruneau, Christian 2016-08-22 Remarkable innovations have been made in the field of olefin metathesis due to the design and preparation of new catalysts. Ethenolysis, which is cross-metathesis with ethylene, represents one catalytic transformation that has been used with the purpose of cleaving internal carbon-carbon double bonds. The objectives were either the ring opening of cyclic olefins to produce dienes or the shortening of unsaturated hydrocarbon chains to degrade polymers or generate valuable shorter terminal olefins in a controlled manner. This Review summarizes several aspects of this reaction: the catalysts, their degradation in the presence of ethylene, some parameters driving their productivity, the side reactions, and the applications of ethenolysis in organic synthesis and in potential industrial applications. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
4. Supported organometallic catalysts for hydrogenation and Olefin Polymerization DOEpatents Marks, Tobin J.; Ahn, Hongsang 2001-01-01 Novel heterogeneous catalysts for the which hydrogenation of olefins and arenes with high conversion rates under ambient conditions and the polymerization of olefins have been developed. The catalysts are synthesized from Ziegler-type precatalysts by supporting them on sulfate-modified zirconia.
5. Theoretical study of photoinduced epoxidation of olefins catalyzed by ruthenium porphyrin. PubMed Ishikawa, Atsushi; Sakaki, Shigeyoshi 2011-05-12 Epoxidation of olefin by [Ru[TMP][CO][O]][-] [TMP = tetramesitylporphine], which is a key step of the photocatalyzed epoxidation of olefin by [Ru[TMP][CO]], is studied mainly with the density functional theory [DFT] method, where [Ru[Por][CO]] is employed as a model complex [Por = unsubstituted porphyrin]. The CASSCF method was also used to investigate the electronic structure of important species in the catalytic cycle. In all of the ruthenium porphyrin species involved in the catalytic cycle, the weight of the main configuration of the CASSCF wave function is larger than 85%, suggesting that the static correlation is not very large. Also, unrestricted-DFT-calculated natural orbitals are essentially the same as CASSCF-calculated ones, here. On the basis of these results, we employed the DFT method in this work. Present computational results show characteristic features of this reaction, as follows: [i] The epoxidation reaction occurs via carboradical-type transition state. Neither carbocation-type nor concerted oxene-insertion-type character is observed in the transition state. [ii] Electron and spin populations transfer from the olefin moiety to the porphyrin ring in the step of the C-O bond formation. [iii] Electron and spin populations of the olefin and porphyrin moieties considerably change around the transition state. [iv] The atomic and spin populations of Ru change little in the reaction, indicating that the Ru center keeps the +II oxidation state in the whole catalytic cycle. [v] The stability of the olefin adduct [Ru[Por][CO][O][olefin]][-] considerably depends on the kind of olefin, such as ethylene, n-hexene, and styrene. In particular, styrene forms a stable olefin adduct. And, [vi] interestingly, the difference in the activation barrier among these olefins is small in the quantitative level [within 5 kcal/mol], indicating that this catalyst can be applied to various substrates. This is because the stabilities and electronic structures of both the
6. A chameleon catalyst for nonheme iron-promoted olefin oxidation. PubMed Iyer, Shyam R; Javadi, Maedeh Moshref; Feng, Yan; Hyun, Min Young; Oloo, Williamson N; Kim, Cheal; Que, Lawrence 2014-11-18 We report the chameleonic reactivity of two nonheme iron catalysts for olefin oxidation with H2O2 that switch from nearly exclusive cis-dihydroxylation of electron-poor olefins to the exclusive epoxidation of electron-rich olefins upon addition of acetic acid. This switching suggests a common precursor to the nucleophilic oxidant proposed to Fe[III]-η[2]-OOH and electrophilic oxidant proposed to Fe[V][O][OAc], and reversible coordination of acetic acid as a switching pathway.
7. Inhibiting Sterilization-Induced Oxidation of Large Molecule Therapeutics Packaged in Plastic Parenteral Vials. PubMed Vieregg, Jeffrey R; Martin, Steven J; Breeland, Adam P; Weikart, Christopher M; Tirrell, Matthew V 2018-01-01 For many years, glass has been the default material for parenteral packaging, but the development of advanced plastics such as cyclic olefin polymers and the rapidly increasing importance of biologic drugs have provided new choices, as well as more stringent performance requirements. In particular, many biologics must be stored at non-neutral pH, where glass is susceptible to hydrolysis, metal extraction, and delamination. Plastic containers are not susceptible to these problems, but suffer from higher gas permeability and a propensity for sterilization-induced radical generation, heightening the risk of oxidative damage to sensitive drugs. This study evaluates the properties of a hybrid material, SiOPlas™, in which an ultrathin multilayer coating is applied to the interior of cyclic olefin polymer containers via plasma-enhanced chemical vapor deposition. Our results show that the coating decreases oxygen permeation through the vial walls 33-fold compared to uncoated cyclic olefin polymers, which should allow for improved control of oxygen levels in sensitive formulations. We also measured degradation of two biologic drugs that are known to be sensitive to oxidation, teriparatide and erythropoietin, in gamma and electron beam sterilized SiOPlas™, glass, and uncoated cyclic olefin polymer vials. In both cases, solutions stored in SiOPlas™ vials did not show elevated susceptibility to oxidation compared to either glass or unsterilized controls. Taken together, these results suggest that hybrid materials such as SiOPlas™ are attractive choices for storing high-value biologic drugs. LAY ABSTRACT: One of the most important functions of parenteral drug containers is safeguarding their contents from damage, either chemical or physical. Glass has been the container material of choice for many years, but concerns over breakage and vulnerability to chemical attack at non-neutral pH have spurred the rise of advanced plastics as alternatives. Plastics solve many
8. Electrochemistry for biofuel generation: transformation of fatty acids and triglycerides to diesel-like olefin/ether mixtures and olefins. PubMed dos Santos, Tatiane R; Harnisch, Falk; Nilges, Peter; Schröder, Uwe 2015-03-01 Electroorganic synthesis can be exploited for the production of biofuels from fatty acids and triglycerides. With Coulomb efficiencies [CE] of up to 50 %, the electrochemical decarboxylation of fatty acids in methanolic and ethanolic solutions leads to the formation of diesel-like olefin/ether mixtures. Triglycerides can be directly converted in aqueous solutions by using sonoelectrochemistry, with olefins as the main products [with a CE of more than 20 %]. The latter reaction, however, is terminated at around 50 % substrate conversion by the produced side-product glycerol. An energy analysis shows that the electrochemical olefin synthesis can be an energetically competitive, sustainable, and--in comparison with established processes--economically feasible alternative for the exploitation of fats and oils for biofuel production. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
9. Two-photon excitation in chip electrophoresis enabling label-free fluorescence detection in non-UV transparent full-body polymer chips. PubMed Geissler, David; Belder, Detlev 2015-12-01 One of the most commonly employed detection methods in microfluidic research is fluorescence detection, due to its ease of integration and excellent sensitivity. Many analytes though do not show luminescence when excited in the visible light spectrum, require suitable dyes. Deep-ultraviolet [UV] excitation [ 20:1]. Asymmetric catalysis with chiral iron[II] complexes and preliminary mechanistic studies reveal an iron nitrenoid is a possible intermediate that can undergo either aminohydroxylation or aziridination, and the selectivity can be controlled by careful selection of counteranion/ligand combinations.
10. Entrapped Single Tungstate Site in Zeolite for Cooperative Catalysis of Olefin Metathesis with Brønsted Acid Site DOE Office of Scientific and Technical Information [OSTI.GOV] Zhao, Pu; Ye, Lin; Sun, Zhenyu Industrial olefin metathesis catalysts generally suffer from low reaction rates and require harsh reaction conditions for moderate activities. This is due to their inability to prevent metathesis active sites [MAS] from aggregation and their intrinsic poor adsorption and activation of olefin molecules. Here, isolated tungstate species as single molecular MAS is immobilized inside zeolite pores by Bronsted acid sites [BAS] on the inner surface. It is demonstrated for the first time that unoccupied BAS in atomic proximity to MAS enhance olefin adsorption and greatly facilitate the formation of metallocycle intermediates in a stereospecific manner. Thus, effective cooperative catalysis takes placemore » over the BAS-MAS pair. In consequence, for the cross-metathesis of ethene and trans-2-butene to propene, under the same mild reaction conditions, the propene production rate over WOx/USY is ca. 7,300 times that over the industrial WO3/SiO2 based catalyst. A propene yield up to 79% [80% selectivity] without observable deactivation was obtained over WOx/USY for a wide range of reaction conditions.« less
11. Catalysis by cytochrome P-450 of an oxidative reaction in xenobiotic aldehyde metabolism: deformylation with olefin formation. PubMed Central Roberts, E S; Vaz, A D; Coon, M J 1991-01-01 As we have briefly described elsewhere, cytochrome P-450 catalyzes the oxidative deformylation of cyclohexane carboxaldehyde to yield cyclohexene and formic acid in a reaction believed to involve a peroxyhemiacetal-like adduct formed between the substrate and molecular oxygen-derived hydrogen peroxide. This reaction is a useful model for the demethylation reactions catalyzed by the steroidogenic P-450s, aromatase, and lanosterol demethylase. In the present study, the cytochrome P-450-catalyzed formation of olefinic products from a series of xenobiotic aldehydes has been demonstrated. Isobutyraldehyde and trimethylacetaldehyde, but not propionaldehyde, are converted to the predicted olefinic products, suggesting a requirement for branching at the alpha carbon. In addition, the four C5 aldehydes of similar hydrophobicity were compared for their ability to undergo the reaction. The straight-chain valeraldehyde gave no olefinic products with five different rabbit liver microsomal P-450 isozymes. However, increasing activity was seen with the other isomers in the order of isovaleraldehyde, 2-methylbutyraldehyde, and trimethylacetaldehyde, with all of the P-450 cytochromes. The catalytic rate with trimethylacetaldehyde is highest with antibiotic-inducible P-450 form 3A6, followed by phenobarbital-inducible form 2B4 and ethanol-inducible form 2E1. Citronellal, a beta-branched aldehyde that is found in many essential oils and is widely used as an odorant and a flavorant, was found to undergo the oxidative deformylation reaction to yield 2,6-dimethyl-1,5-heptadiene, but only with P-450 2B4. The oxidative cleavage reaction with olefin formation appears to be widespread, as judged by the variety of aldehydes that serve as substrates and of P-450 cytochromes that serve as catalysts. PMID:1924356
12. Bond–Slip Relationship for CFRP Sheets Externally Bonded to Concrete under Cyclic Loading PubMed Central Li, Ke; Cao, Shuangyin; Yang, Yue; Zhu, Juntao 2018-01-01 The objective of this paper was to explore the bond–slip relationship between carbon fiber-reinforced polymer [CFRP] sheets and concrete under cyclic loading through experimental and analytical approaches. Modified beam tests were performed in order to gain insight into the bond–slip relationship under static and cyclic loading. The test variables are the CFRP-to-concrete width ratio, and the bond length of the CFRP sheets. An analysis of the test results in this paper and existing test results indicated that the slope of the ascending segment of the bond–slip curve decreased with an increase in the number of load cycles, but the slip corresponding to the maximum shear stress was almost invariable as the number of load cycles increased. In addition, the rate of reduction in the slope of the ascending range of the bond–slip curve during cyclic loading decreased as the concrete strength increased, and increased as the load level or CFRP-to-concrete width ratio enhanced. However, these were not affected by variations in bond length if the residual bond length was longer than the effective bond length. A bilinear bond–slip model for CFRP sheets that are externally bonded to concrete under cyclic loading, which considered the effects of the cyclic load level, concrete strength, and CFRP-to-concrete ratio, was developed based on the existing static bond–slip model. The accuracy of this proposed model was verified by a comparison between this proposed model and test results. PMID:29495383
13. Bond-Slip Relationship for CFRP Sheets Externally Bonded to Concrete under Cyclic Loading. PubMed Li, Ke; Cao, Shuangyin; Yang, Yue; Zhu, Juntao 2018-02-26 The objective of this paper was to explore the bond-slip relationship between carbon fiber-reinforced polymer [CFRP] sheets and concrete under cyclic loading through experimental and analytical approaches. Modified beam tests were performed in order to gain insight into the bond-slip relationship under static and cyclic loading. The test variables are the CFRP-to-concrete width ratio, and the bond length of the CFRP sheets. An analysis of the test results in this paper and existing test results indicated that the slope of the ascending segment of the bond-slip curve decreased with an increase in the number of load cycles, but the slip corresponding to the maximum shear stress was almost invariable as the number of load cycles increased. In addition, the rate of reduction in the slope of the ascending range of the bond-slip curve during cyclic loading decreased as the concrete strength increased, and increased as the load level or CFRP-to-concrete width ratio enhanced. However, these were not affected by variations in bond length if the residual bond length was longer than the effective bond length. A bilinear bond-slip model for CFRP sheets that are externally bonded to concrete under cyclic loading, which considered the effects of the cyclic load level, concrete strength, and CFRP-to-concrete ratio, was developed based on the existing static bond-slip model. The accuracy of this proposed model was verified by a comparison between this proposed model and test results.
14. In Silico Olefin Metathesis with Ru-Based Catalysts Containing N-Heterocyclic Carbenes Bearing C60 Fullerenes. PubMed Martínez, Juan Pablo; Vummaleti, Sai Vikrama Chaitanya; Falivene, Laura; Nolan, Steven P; Cavallo, Luigi; Solà, Miquel; Poater, Albert 2016-05-04 Density functional theory calculations have been used to explore the potential of Ru-based complexes with 1,3-bis[2,4,6-trimethylphenyl]imidazolin-2-ylidene [SIMes] ligand backbone [A] being modified in silico by the insertion of a C60 molecule [B and C], as olefin metathesis catalysts. To this end, we investigated the olefin metathesis reaction catalyzed by complexes A, B, and C using ethylene as the substrate, focusing mainly on the thermodynamic stability of all possible reaction intermediates. Our results suggest that complex B bearing an electron-withdrawing N-heterocyclic carbene improves the performance of unannulated complex A. The efficiency of complex B is only surpassed by complex A when the backbone of the N-heterocyclic carbene of complex A is substituted by two amino groups. The particular performance of complexes B and C has to be attributed to electronic factors, that is, the electronic-donating capacity of modified SIMes ligand rather than steric effects, because the latter are predicted to be almost identical for complexes B and C when compared to those of A. Overall, this study indicates that such Ru-based complexes B and C might have the potential to be effective olefin metathesis catalysts. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
15. Nickel-Catalyzed, Carbonyl-Ene-Type Reactions: Selective for Alpha Olefins and More Efficient with Electron-Rich Aldehydes PubMed Central Ho, Chun-Yu; Ng, Sze-Sze; Jamison, Timothy F. 2011-01-01 Described are several classes of unusual or unprecedented carbonyl-ene-type reactions, including those between alpha olefins and aromatic aldehydes. Catalyzed by nickel, these processes complement existing Lewis acid-catalyzed methods in several respects. Not only are monosubstituted alkenes, aromatic aldehydes, and tert-alkyl aldehydes effective substrates, but monosubstituted olefins also react faster than those that are more substituted, and large or electron-rich aldehydes are more effective than small or electron-poor ones. Conceptually, in the presence of a nickel-phosphine catalyst, the combination of off-the-shelf alkenes, silyl triflates, and triethylamine functions as a replacement for an allylmetal reagent. PMID:16620106
16. Alkyl substituted cyclic ethers in 2,300 M yr old Transvaal algal stromatolite NASA Technical Reports Server [NTRS] Zumberge, J. E.; Nagy, B. 1975-01-01 Two cyclic ethers have been identified for the first time from insoluble polymer-like kerogen in a Precambrian rock by ozonolysis, gas chromatography, and mass spectrometry. The ethers are 2-n-propyl-3-methyltetrahydrofuran and 2-n-propyltetrahydropyran. These compounds could prove to be the oldest indigenous biochemical fossils. The sample was obtained 750 m stratigraphically above the base of the Transvaal Sequence from an outcrop approximately 315 km north-east of Johannesburg, South Africa.
17. Amperometric detector designs for capillary electrophoresis microchips. PubMed Castaño-Alvarez, Mario; Fernández-Abedul, M Teresa; Costa-García, Agustín 2006-03-24 Electrochemical [EC] detection is a sensitive and miniaturisable detection mode for capillary electrophoresis [CE] microchips. Detection cell design is very important in order to ensure electrical isolation from the high separation voltage. Amperometric detectors with different designs have been developed for coupling EC detection to CE-microchips. Different working electrode alignment: in-channel or end-channel has been tested in conjunction with several materials: gold, platinum or carbon. The end-channel detector was based on a platinum or gold wire manually aligned at the exit of the separation channel. Thick- [screen-printed carbon electrode] and thin-film [sputtered gold film] electrodes have also been employed with this configuration, but with a different design that allowed the rapid replacement of the electrode. The in-channel detector was based on a gold film within the separation channel. A gold-based dual electrode detector, which combined for the first time in- and end-channel detection, has been also tested. These amperometric detectors have been evaluated in combination to poly[methylmethacrylate] [PMMA] and Topas [thermoplastic olefin polymer of amorphous structure] CE-microchips. Topas is a new and promising cyclic olefin copolymer with high chemical resistance. Relevant parameters of the polymer microchip separation such as precision, efficiency or resolution and amperometric detection were studied with the different detector designs using p-aminophenol and L-ascorbic acid as model analytes in Tris-based buffer pH 9.0.
18. Application of encapsulated superabsorbent polymers in cementitious materials for stimulated autogenous healing NASA Astrophysics Data System [ADS] Pelto, Jani; Leivo, Markku; Gruyaert, Elke; Debbaut, Brenda; Snoeck, Didier; De Belie, Nele 2017-10-01 Superabsorbent polymers have shown potential for use in mortar and concrete as self-healing agents. The main drawback is, however, that these superabsorbent polymers also absorb mixing water during the preparation and casting of mortar or concrete, leading to a loss in workability. To avoid the absorption of mixing water, superabsorbent polymers were coated using a fluid bed spraying process. The barrier coating consisted of three successive coating layers: polyvinylbutyral as primer/wetting layer, cyclo-olefin copolymer as a barrier layer and a sol-gel derived zirconium-silicon oxide as an adhesion-promoting topcoat layer. The coated SAPs were characterized, and their swelling determined to quantify the delay in uptake of water and Ca[OH]2 solution. The last was considered as the most important, as the SAPs will finally be applied in mortar or concrete having a pore solution with high pH. The results showed that swelling could be delayed to a large extent, but for a short time. Results showed that the self-sealing efficiency of mortars was not affected by coating the SAPs. Moreover, due to the reduced uptake of mixing water, the strength reduction, noticed when uncoated SAPs were added to the mortar, could partly be compensated.
19. Electroactive Polymer Nanoparticles Exhibiting Photothermal Properties PubMed Central Cantu, Travis; Rodier, Bradley; Iszard, Zachary; Kilian, Alissa; Pattani, Varun; Walsh, Kyle; Weber, Katharina; Tunnell, James; Betancourt, Tania; Irvin, Jennifer 2016-01-01 A method for the synthesis of electroactive polymers is demonstrated, starting with the synthesis of extended conjugation monomers using a three-step process that finishes with Negishi coupling. Negishi coupling is a cross-coupling process in which a chemical precursor is first lithiated, followed by transmetallation with ZnCl2. The resultant organozinc compound can be coupled to a dibrominated aromatic precursor to give the conjugated monomer. Polymer films can be prepared via electropolymerization of the monomer and characterized using cyclic voltammetry and ultraviolet-visible-near infrared [UV-Vis-NIR] spectroscopy. Nanoparticles [NPs] are prepared via emulsion polymerization of the monomer using a two-surfactant system to yield an aqueous dispersion of the polymer NPs. The NPs are characterized using dynamic light scattering, electron microscopy, and UV-Vis-NIR-spectroscopy. Cytocompatibility of NPs is investigated using the cell viability assay. Finally, the NP suspensions are irradiated with a NIR laser to determine their effectiveness as potential materials for photothermal therapy [PTT]. PMID:26780244

1. Assessment of Composite Delamination Self-Healing Under Cyclic Loading NASA Technical Reports Server [NTRS] O'Brien, T. Kevin 2009-01-01 Recently, the promise of self-healing materials for enhanced autonomous durability has been introduced using a micro-encapsulation technique where a polymer based healing agent is encapsulated in thin walled spheres and embedded into a base polymer along with a catalyst phase. For this study, composite skin-stiffener flange debonding specimens were manufactured from composite prepreg containing interleaf layers with a polymer based healing agent encapsulated in thin-walled spheres. Constant amplitude fatigue tests in three-point bending showed the effect of self-healing on the fatigue response of the skin-stiffener flange coupons. After the cycling that created debonding, fatigue tests were held at the mean load for 24 hours. For roughly half the specimens tested, when the cyclic loading was resumed a decrease in compliance [increase in stiffness] was observed, indicating that some healing had occurred. However, with continued cycling, the specimen compliance eventually increased to the original level before the hold, indicating that the damage had returned to its original state. As was noted in a prevoius study conducted with specimens tested under monotonically increasing loads to failure, healing achieved via the micro-encapsulation technique may be limited to the volume of healing agent available relative to the crack volume.
2. Nobel Chemistry in the Laboratory: Synthesis of a Ruthenium Catalyst for Ring-Closing Olefin Metathesis--An Experiment for the Advanced Inorganic or Organic Laboratory ERIC Educational Resources Information Center Greco, George E. 2007-01-01 An experiment for the upper-level undergraduate laboratory is described in which students synthesize a ruthenium olefin metathesis catalyst, then use the catalyst to carry out the ring-closing metathesis of diethyl diallylmalonate. The olefin metathesis reaction was the subject of the 2005 Nobel Prize in chemistry. The catalyst chosen for this…
3. Communication: The simplified generalized entropy theory of glass-formation in polymer melts DOE Office of Scientific and Technical Information [OSTI.GOV] Freed, Karl F. 2015-08-07 While a wide range of non-trivial predictions of the generalized entropy theory [GET] of glass-formation in polymer melts agree with a large number of observed universal and non-universal properties of these glass-formers and even for the dependence of these properties on monomer molecular structure, the huge mathematical complexity of the theory precludes its extension to describe, for instance, the perplexing, complex behavior observed for technologically important polymer films with thickness below ∼100 nm and for which a fundamental molecular theory is lacking for the structural relaxation. The present communication describes a hugely simplified version of the theory, called the simplifiedmore » generalized entropy theory [SGET] that provides one component necessary for devising a theory for the structural relaxation of thin polymer films and thereby supplements the first required ingredient, the recently developed Flory-Huggins level theory for the thermodynamic properties of thin polymer films, before the concluding third step of combining all the components into the SGET for thin polymer films. Comparisons between the predictions of the SGET and the full GET for the four characteristic temperatures of glass-formation provide good agreement for a highly non-trivial model system of polymer melts with chains of the structure of poly[n-α olefins] systems where the GET has produced good agreement with experiment. The comparisons consider values of the relative backbone and side group stiffnesses such that the glass transition temperature decreases as the amount of excess free volume diminishes, contrary to general expectations but in accord with observations for poly[n-alkyl methacrylates]. Moreover, the SGET is sufficiently concise to enable its discussion in a standard course on statistical mechanics or polymer physics.« less
4. Synthesis gas and olefins from the catalytic autothermal reforming of volatile and non-volatile liquids NASA Astrophysics Data System [ADS] Dreyer, Bradon Justin 2007-12-01 The research presented in this thesis develops an understanding of a clean energy process technology, catalytic partial oxidation [CPO]. CPO is a process in which a carbon containing fuel, such as a hydrocarbon, is passed over a noble metal catalyst [e.g. rhodium and platinum] to efficiently generate synthesis gas [H2 and CO] and olefins [e.g. ethylene and propylene] in millisecond contact times. Chapter 1 introduces CPO and compares this technology with conventional methods for synthesis gas and olefin production. CPO has several advantages over the traditional synthesis gas and olefin production methods. One advantage includes autothermal operation, requiring no external heat input from furnaces or heat exchangers. Autothermal operation allows these reactors to be built compactly. The short contact-times associated with CPO further enable for high throughput in relatively small reactor systems, and more compact reactors typically translate to faster response times if transient operation is required. Nobel metal based CPO catalysts are also resistant to deactivation, resulting in less catalyst replacement, regeneration, and maintenance, and an increase in operating efficiency. An overview of the many applications of the chemicals produced from CPO is also presented in Chapter 1. The chemicals produced are crucial in generating valuable chemical intermediates that are eventually incorporated in consumer products, medical devices, building structures, and fertilizers. Additionally, H2 can be used as a source of energy in mobile fuel applications. Fuel cells convert H2 and O2 into electricity and water at higher efficiencies than thermal engine generators. Due to the difficulties in H2 storage, these more efficient energy generators are dependent on hydrogen obtained from synthesis gas production in compact, portable fuel reformers, such as CPO reactors. Furthermore, H2 and CO can be used in reducing environmentally harmful emissions. Particularly, the implementation
5. Revealing the Influence of Silver in Ni-Ag Catalysts on the Selectivity of Higher Olefin Synthesis from Stearic Acid NASA Astrophysics Data System [ADS] Danyushevsky, V. Ya.; Murzin, V. Yu.; Kuznetsov, P. S.; Shamsiev, R. S.; Katsman, E. A.; Khramov, E. V.; Zubavichus, Y. V.; Berenblyum, A. S. 2018-01-01 Results on the conversion of stearic acid to olefins over Ni-Ag/γ-Al2O3 catalysts are presented. XANES and EXAFS experiments in situ and DFT calculations were applied to reveal the structure of active sites therein. It is shown that the introduction of Ag to Ni catalysts leads to an increase in the olefin yield. After a reduction in hydrogen [350°C, 3 h] alumina-supported nanoparticles of nickel sulfides and metallic Ag are formed. The role of metal hydrides formed during the reaction is extensively discussed.
6. Active polymer materials for optical fiber CO2 sensors NASA Astrophysics Data System [ADS] Wysokiński, Karol; Filipowicz, Marta; Stańczyk, Tomasz; Lipiński, Stanisław; Napierała, Marek; Murawski, Michał; Nasiłowski, Tomasz 2017-04-01 CO2 optical fiber sensors based on polymer active materials are presented in this paper. Ethyl cellulose was proven to be a good candidate for a matrix material of the sensor, since it gives porous, thick and very sensitive layers. Low-cost sensors based on polymer optical fibers have been elaborated. Sensors have been examined for their sensitivity to CO2, temperature and humidity. Response time during cyclic exposures to CO2 have been also determined. Special layers exhibiting irreversible change of color during exposure to carbon dioxide have been developed. They have been verified for a possible use in smart food packaging.
7. Cyclic Multiblock Copolymers via Combination of Iterative Cu[0]-Mediated Radical Polymerization and Cu[I]-Catalyzed Azide-Alkyne Cycloaddition Reaction. PubMed Xiao, Lifen; Zhu, Wen; Chen, Jiqiang; Zhang, Ke 2017-02-01 Cyclic multiblock polymers with high-order blocks are synthesized via the combination of single-electron transfer living radical polymerization [SET-LRP] and copper-catalyzed azide-alkyne cycloaddition [CuAAC]. The linear α,ω-telechelic multiblock copolymer is prepared via SET-LRP by sequential addition of different monomers. The SET-LRP approach allows well control of the block length and sequence as A-B-C-D-E, etc. The CuAAC is then performed to intramolecularly couple the azide and alkyne end groups of the linear copolymer and produce the corresponding cyclic copolymer. The block sequence and the cyclic topology of the resultant cyclic copolymer are confirmed by the characterization of 1 H nuclear magnetic resonance spectroscopy, gel permeation chromatography, Fourier transform infrared spectroscopy, and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
8. New secondary batteries utilizing electronically conductive polymer cathodes NASA Technical Reports Server [NTRS] Martin, Charles R.; White, Ralph E. 1989-01-01 The objectives of this project are to characterize the transport properties in electronically conductive polymers and to assess the utility of these films as cathodes in lithium/polymer secondary batteries. During this research period, progress has been made in a literature survey of the historical background, methods of preparation, the physical and chemical properties, and potential technological applications of polythiophene. Progress has also been made in the characterization of polypyrrole flat films and fibrillar films. Cyclic voltammetry and potential step chronocoulometry were used to gain information on peak currents and potentials switching reaction rates, charge capacity, and charge retention. Battery charge/discharge studies were also performed.
9. Homogeneous dihydroxylation of olefins catalyzed by OsO[4][2-] immobilized on a dendritic backbone with a tertiary nitrogen at its core position. PubMed Fujita, Ken-Ichi; Inoue, Kensuke; Tsuchimoto, Teruhisa; Yasuda, Hiroyuki 2012-01-01 OsO[4][2-] immobilized on a poly[benzyl ether] dendrimer with a tertiary nitrogen at its core position efficiently catalyzed the homogeneous dihydroxylation of olefins with a low level of osmium leaching. The dendritic osmium catalyst could be applied to the wide range of olefins. Furthermore, the dendritic osmium catalyst was recovered by reprecipitation and then reused up to five times.
10. A Continuum Damage Mechanics Model for the Static and Cyclic Fatigue of Cellular Composites PubMed Central Huber, Otto 2017-01-01 The fatigue behavior of a cellular composite with an epoxy matrix and glass foam granules is analyzed and modeled by means of continuum damage mechanics. The investigated cellular composite is a particular type of composite foam, and is very similar to syntactic foams. In contrast to conventional syntactic foams constituted by hollow spherical particles [balloons], cellular glass, mineral, or metal place holders are combined with the matrix material [metal or polymer] in the case of cellular composites. A microstructural investigation of the damage behavior is performed using scanning electron microscopy. For the modeling of the fatigue behavior, the damage is separated into pure static and pure cyclic damage and described in terms of the stiffness loss of the material using damage models for cyclic and creep damage. Both models incorporate nonlinear accumulation and interaction of damage. A cycle jumping procedure is developed, which allows for a fast and accurate calculation of the damage evolution for constant load frequencies. The damage model is applied to examine the mean stress effect for cyclic fatigue and to investigate the frequency effect and the influence of the signal form in the case of static and cyclic damage interaction. The calculated lifetimes are in very good agreement with experimental results. PMID:28809806
11. Electrically and Thermally Conductive Carbon Fibre Fabric Reinforced Polymer Composites Based on Nanocarbons and an In-situ Polymerizable Cyclic Oligoester. PubMed Jang, Ji-Un; Park, Hyeong Cheol; Lee, Hun Su; Khil, Myung-Seob; Kim, Seong Yun 2018-05-16 There is growing interest in carbon fibre fabric reinforced polymer [CFRP] composites based on a thermoplastic matrix, which is easy to rapidly produce, repair or recycle. To expand the applications of thermoplastic CFRP composites, we propose a process for fabricating conductive CFRP composites with improved electrical and thermal conductivities using an in-situ polymerizable and thermoplastic cyclic butylene terephthalate oligomer matrix, which can induce good impregnation of carbon fibres and a high dispersion of nanocarbon fillers. Under optimal processing conditions, the surface resistivity below the order of 10 +10 Ω/sq, which can enable electrostatic powder painting application for automotive outer panels, can be induced with a low nanofiller content of 1 wt%. Furthermore, CFRP composites containing 20 wt% graphene nanoplatelets [GNPs] were found to exhibit an excellent thermal conductivity of 13.7 W/m·K. Incorporating multi-walled carbon nanotubes into CFRP composites is more advantageous for improving electrical conductivity, whereas incorporating GNPs is more beneficial for enhancing thermal conductivity. It is possible to fabricate the developed thermoplastic CFRP composites within 2 min. The proposed composites have sufficient potential for use in automotive outer panels, engine blocks and other mechanical components that require conductive characteristics.
12. A mathematical model for predicting cyclic voltammograms of electronically conductive polypyrrole NASA Technical Reports Server [NTRS] Yeu, Taewhan; Nguyen, Trung V.; White, Ralph E. 1988-01-01 Polypyrrole is an attractive polymer for use as a high-energy-density secondary battery because of its potential as an inexpensive, lightweight, and noncorrosive electrode material. A mathematical model to simulate cyclic voltammograms for polypyrrole is presented. The model is for a conductive porous electrode film on a rotating disk electrode [RDE] and is used to predict the spatial and time dependence of concentration, overpotential, and stored charge profiles within a polypyrrole film. The model includes both faradic and capacitance charge components in the total current density expression.
13. A mathematical model for predicting cyclic voltammograms of electronically conductive polypyrrole NASA Technical Reports Server [NTRS] Yeu, Taewhan; Nguyen, Trung V.; White, Ralph E. 1987-01-01 Polypyrrole is an attractive polymer for use as a high-energy-density secondary battery because of its potential as an inexpensive, lightweight, and noncorrosive electrode material. A mathematical model to simulate cyclic voltammograms for polypyrrole is presented. The model is for a conductive porous electrode film on a rotating disk electrode [RDE] and is used to predict the spatial and time dependence of concentration, overpotential, and stored charge profiles within a polypyrrole film. The model includes both faradic and capacitance charge components in the total current density expression.
14. Enhanced catalytic performance for light-olefins production from chloromethane over hierarchical porous ZSM-5 zeolite synthesized by a growth-inhibition strategy NASA Astrophysics Data System [ADS] Liu, Qing; Wen, Dafen; Yang, Yanran; Fei, Zhaoyang; Zhang, Zhuxiu; Chen, Xian; Tang, Jihai; Cui, Mifen; Qiao, Xu 2018-03-01 Hierarchical porous ZSM-5 [HP-ZSM-5] zeolites were synthesized by hydrothermal crystallization method adding triethoxyvinylsilane as the growth-inhibitor at different hydrothermal crystallized temperatures. The properties of the obtained samples were characterized by XRD, SEM, N2-sorption, uptake of ethylene, 27Al MAS NMR, NH3-TPD, and Py-IR. It was found that the mesopore was introduced and the acidity was adjusted over HP-ZSM-5 samples successfully. The hydrothermal crystallized temperature had an important influence on the porous structure and surface properties. The catalytic performance for chloromethane to light-olefins [CMTO] were also investigated. Compared with ZSM-5 samples, HP-ZSM-5 samples exhibited enhanced stability and increased selectivity of light-olefins for CMTO reaction because of the introduction of the abundant mesopore and appropriate acidity. The lifetime [the duration of chloromethane conversion >98%] and selectivity of light-olefins reached 115 h and 69.3%, respectively.
15. Heteropolytungstate nanoparticles: Microemulsion-mediated preparation and investigation of their catalytic activity in the epoxidation of olefins DOE Office of Scientific and Technical Information [OSTI.GOV] Masteri-Farahani, M., E-mail: mfarahany@yahoo.com; Ghorbani, M. 2016-04-15 Highlights: • Keggin type Q{sub 3}PW{sub 12}O{sub 40} nanoparticles were synthesized by using microemulsion system. • The nanoparticles have uniform size of about 25 nm and spherical morphologies. • The prepared nanoparticles act as reusable catalyst in the epoxidation of olefins with H{sub 2}O{sub 2}. - Abstract: Keggin type Q{sub 3}PW{sub 12}O{sub 40} nanoparticles [Q = cetyltrimethylammonium cation] were synthesized in water-in-oil [w/o] microemulsion consisted of water/cetyltrimethylammonium bromide/n-butanol/isooctane. Reaction of Na{sub 2}WO{sub 4}, Na{sub 2}HPO{sub 4} and hydrochloric acid within water containing nanoreactors of reverse micelles resulted in the preparation of Q{sub 3}PW{sub 12}O{sub 40} nanoparticles. The resultant nanoparticles weremore » analyzed by physicochemical methods such as FT-IR spectroscopy, X-ray diffraction, energy-dispersive X-ray analysis, thermogravimetric analyses [TGA-DTA], scanning and transmission electron microscopy and atomic force microscopy which show nearly uniform spherical nanoparticles with size of about 15 nm. Finally, catalytic activity of the Q{sub 3}PW{sub 12}O{sub 40} nanoparticles was examined in the epoxidation of olefins with H{sub 2}O{sub 2}. The prepared nanoparticles acted as recoverable and reusable catalyst in the epoxidation of olefins with H{sub 2}O{sub 2}.« less
16. Accelerated Thermal Depolymerization of Cyclic Polyphthalaldehyde with a Polymeric Thermoacid Generator. PubMed Lopez Hernandez, Hector; Lee, Olivia P; Possanza, Catherine; Kaitz, Joshua A; Park, Chan Woo; Plantz, Christopher L; Moore, Jeffrey S; White, Scott R 2018-04-30 Thermally triggerable polymer films that degrade at modest temperatures [≈85 °C] are created from a blend of cyclic polyphthalaldehyde [cPPA] and a polymeric thermoacid generator, poly[vinyl tert-butyl carbonate sulfone] [PVtBCS]. PVtBCS depolymerizes when heated, generating acid which initiates the depolymerization of cPPA into volatile byproducts. The mass loss onset for 2 wt% PVtBCS/cPPA is 22 °C lower than the onset for neat cPPA alone in dynamic thermogravimetric analysis experiments. Increased concentrations of PVtBCS increase the rate of depolymerization of cPPA. Raman spectroscopy reveals that the monomer, o-phthalaldehyde, is the main depolymerization product of the acid-catalyzed depolymerization of cPPA. The PVtBCS/cPPA blend is a promising material for the design and manufacture of transient electronic packaging and polymers. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
17. Coke formation and carbon atom economy of methanol-to-olefins reaction. PubMed Wei, Yingxu; Yuan, Cuiyu; Li, Jinzhe; Xu, Shutao; Zhou, You; Chen, Jingrun; Wang, Quanyi; Xu, Lei; Qi, Yue; Zhang, Qing; Liu, Zhongmin 2012-05-01 The methanol-to-olefins [MTO] process is becoming the most important non-petrochemical route for the production of light olefins from coal or natural gas. Maximizing the generation of the target products, ethene and propene, and minimizing the production of byproducts and coke, are major considerations in the efficient utilization of the carbon resource of methanol. In the present work, the heterogeneous catalytic conversion of methanol was evaluated by performing simultaneous measurements of the volatile products generated in the gas phase and the confined coke deposition in the catalyst phase. Real-time and complete reaction profiles were plotted to allow the comparison of carbon atom economy of methanol conversion over the catalyst SAPO-34 at varied reaction temperatures. The difference in carbon atom economy was closely related with the coke formation in the SAPO-34 catalyst. The confined coke compounds were determined. A new type of confined organics was found, and these accounted for the quick deactivation and low carbon atom economy under low-reaction-temperature conditions. Based on the carbon atom economy evaluation and coke species determination, optimized operating conditions for the MTO process are suggested; these conditions guarantee high conversion efficiency of methanol. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
18. Local conformation and intermolecular interaction of rigid ring polymers are not always the same as the linear analogue: cyclic amylose tris[phenylcarbamate] in Θ solvents. PubMed Asano, Natsuki; Kitamura, Shinichi; Terao, Ken 2013-08-15 Small-angle X-ray scattering and static and dynamic light scattering measurements were made for cyclic amylose tris[phenylcarbamate] [cATPC] of which weight-average molar mass M[w] ranges from 1.3 × 10[4] to 1.5 × 10[5] to determine their z-average mean square radius of gyration z, particle scattering function P[q], hydrodynamic radius R[H], and second virial coefficient A2 in methyl acetate [MEA], ethyl acetate [EA], and 4-methyl-2-pentanone [MIBK]. The obtained z, P[q], and R[H] data were analyzed in terms of the wormlike ring to estimate the helix pitch per residue h and the Kuhn segment length λ[-1] [the stiffness parameter, twice the persistence length]. Both h and λ[-1] for cATPC in MEA, EA, and MIBK are smaller than those for linear amylose tris[phenylcarbamate] [ATPC] in the corresponding solvent and the discrepancy becomes more significant with increasing the molar volume of the solvent. This indicates that not every rigid ring has the same local helical structure and chain stiffness as that for the linear polymer in the M[w] range investigated while infinitely long ring chains should have the same local conformation. This conformational difference also affects A2. In actuality, negative A2 was observed for cATPC in MIBK at the Θ temperature of linear ATPC whereas intermolecular topological interaction of ring polymers increases A2.
19. Cobalt-cadmium bimetallic porphyrin coordination polymers for electrochemistry application NASA Astrophysics Data System [ADS] Wang, C. Y.; Cui, G. Y.; Ding, D.; Zhou, B. 2018-01-01 In this paper, we used tetra [4-carboxyphenyl] porphyrin [H2TCPP] and metal cadmium, cobalt as reactants to synthesize metal porphyrin coordination polymers that they had different metal ratio. They were expressed as Co1Cd3TCPP, Co1Cd1TCPP, Co3Cd1TCPP, respectively. The results were characterized by X-ray diffraction [XRD], transmission electron microscopy [TEM] and inductively coupled plasma atomic emission spectrometer [ICP]. Herein, a series of metal porphyrin coordination polymers has multiple metal active centers and constructs electrochemistry sensors. In order to increase the conductivity, multi-walled carbon nanotubes [MWCNTs] can be used to modify the electrodes. The polymer/MWCNTs/GCE electrode was studied by cyclic voltammetry and chronoamperometry as sensor for sodium nitrite. The performance of Co1Cd1TCPP/MWCNTs/GCE electrode is best, the sensitivity for sodium nitrite is 350.95 mA M-1 cm-2 and the. The results indicate that metal porphyrin coordination polymers have excellent performance. It also enriches the application of metal porphyrin coordination polymer in electrochemistry sensor.
20. Synthesis of amphiphilic tadpole-shaped linear-cyclic diblock copolymers via ring-opening polymerization directly initiating from cyclic precursors and their application as drug nanocarriers. PubMed Wan, Xuejuan; Liu, Tao; Liu, Shiyong 2011-04-11 We report on the facile synthesis of well-defined amphiphilic and thermoresponsive tadpole-shaped linear-cyclic diblock copolymers via ring-opening polymerization [ROP] directly initiating from cyclic precursors, their self-assembling behavior in aqueous solution, and the application of micellar assemblies as controlled release drug nanocarriers. Starting from a trifunctional core molecule containing alkynyl, hydroxyl, and bromine moieties, alkynyl-[OH]-Br, macrocyclic poly[N-isopropylacrylamide] [c-PNIPAM] bearing a single hydroxyl functionality was prepared by atom transfer radical polymerization [ATRP], the subsequent end group transformation into azide functionality, and finally the intramacromolecular ring closure reaction via click chemistry. The target amphiphilic tadpole-shaped linear-cyclic diblock copolymer, [c-PNIPAM]-b-PCL, was then synthesized via the ROP of ε-caprolactone [CL] by directly initiating from the cyclic precursor. In aqueous solution at 20 °C, [c-PNIPAM]-b-PCL self-assembles into spherical micelles consisting of hydrophobic PCL cores and well-solvated coronas of cyclic PNIPAM segments. For comparison, linear diblock copolymer with comparable molecular weight and composition, [l-PNIPAM]-b-PCL, was also synthesized. It was found that the thermoresponsive coronas of micelles self-assembled from [c-PNIPAM]-b-PCL exhibit thermoinduced collapse and aggregation at a lower critical thermal phase transition temperature [T[c]] compared with those of [l-PNIPAM]-b-PCL. Temperature-dependent drug release profiles from the two types of micelles of [c-PNIPAM]-b-PCL and [l-PNIPAM]-b-PCL loaded with doxorubicin [Dox] were measured, and the underlying mechanism for the observed difference in releasing properties was proposed. Moreover, MTT assays revealed that micelles of [c-PNIPAM]-b-PCL are almost noncytotoxic up to a concentration of 1.0 g/L, whereas at the same polymer concentration, micelles loaded with Dox lead to ∼60% cell death. Overall, chain

1. Semi-crystalline morphologies of linear and cyclic poly[ɛ-caprolactones] in the diffusion-limited film thickness regime NASA Astrophysics Data System [ADS] Kelly, Giovanni; Bergeson, Amelia; Haque, Farihah; Grayson, Scott; Albert, Julie Thin and ultrathin films of semi-crystalline polymers have been studied for decades due to their far-reaching applications including opto-electronic materials and biological studies of drug delivery and cell adhesion. This body of work has focused on every aspect of crystallization, from the fundamental thermodynamics and kinetics of crystal growth to methods for affecting crystalline morphologies via blending with other polymers. Due to significant synthetic challenges, one area where progress has lagged behind is the study of non-linear architectures, especially ring polymers. However, pioneering work by polymer chemists around the world has closed that gap, and we are beginning to observe important differences between ring and linear polymers in bulk materials. As a complement to those advances, this work aims to compare the morphologies of linear and cyclic poly[ɛ-caprolactones] [PCL] observed in heavily-confined ultrathin films where crystal growth is diffusion-limited. Understanding how confinement effects alter morphology will provide invaluable insight into differences in crystal growth as a function of molecular architecture.
2. RUTHENIUM-CATALYZED TANDEM OLEFIN MIGRATION-ALDOL AND MANNICH-TYPE REACTIONS IN IONIC LIQUID. EPA Science Inventory In the presence of a catalytic amount of RuCl2[PPh3]3, a cross-coupling of 3-buten-2-ol with aldehydes and imines was developed via a tandem olefin migration--aldol--Mannich reaction in bmim[PF6]. With In[OAc]3 as a co-catalyst, a-vinylbenzyl alcohol and aldehydes underwent sim...
3. DNA/RNA binding and anticancer/antimicrobial activities of polymer-copper[II] complexes NASA Astrophysics Data System [ADS] Lakshmipraba, Jagadeesan; Arunachalam, Sankaralingam; Riyasdeen, Anvarbatcha; Dhivya, Rajakumar; Vignesh, Sivanandham; Akbarsha, Mohammad Abdulkader; James, Rathinam Arthur 2013-05-01 Water soluble polymer-copper[II] complexes with various degrees of coordination in the polymer chain were synthesized and characterized by elemental analysis, IR, UV-visible and EPR spectra. The DNA/RNA binding behavior of these polymer-copper[II] complexes was examined by UV-visible absorption, emission and circular dichroism spectroscopic methods, and cyclic voltammetry techniques. The binding of the polymer-copper[II] complexes with DNA/RNA was mainly through intercalation but some amount of electrostatic interaction was also observed. This binding capacity increased with the degree of coordination of the complexes. The polymer-copper[II] complex having the highest degree of coordination was subjected to analysis of cytotoxic and antimicrobial properties. The cytotoxicity study indicated that the polymer-copper[II] complexes affected the viability of MCF-7 mammary carcinoma cells, and the cells responded to the treatment with mostly through apoptosis although a few cells succumbed to necrosis. The antimicrobial screening showed activity against some human pathogens.
4. EXPOXIDATION OF OLEFINS AND α,β-UNSATURATED KEYTONES OVER SONOCHEMICALLY PREPARED HYDROXYAPATITES USING HYDROGEN PEROXIDE EPA Science Inventory An effective and environmentally friendly protocol for the epoxidation of olefins and α,β-unsaturated ketones in the presence of hydroxyapatite as catalyst using hydrogen peroxide is described. The catalyst is active and reusable for the selective epoxidation of a variety...
5. Large-Strain Transparent Magnetoactive Polymer Nanocomposites NASA Technical Reports Server [NTRS] Meador, Michael A. 2012-01-01 A document discusses polymer nano - composite superparamagnetic actuators that were prepared by the addition of organically modified superparamagnetic nanoparticles to the polymer matrix. The nanocomposite films exhibited large deformations under a magnetostatic field with a low loading level of 0.1 wt% in a thermoplastic polyurethane elastomer [TPU] matrix. The maximum actuation deformation of the nanocomposite films increased exponentially with increasing nanoparticle concentration. The cyclic deformation actuation of a high-loading magnetic nanocomposite film was examined in a low magnetic field, and it exhibited excellent reproducibility and controllability. Low-loading TPU nanocomposite films [0.1-2 wt%] were transparent to semitransparent in the visible wavelength range, owing to good dispersion of the magnetic nanoparticles. Magnetoactuation phenomena were also demonstrated in a high-modulus, high-temperature polyimide resin with less mechanical deformation.
6. Prilezhaev dihydroxylation of olefins in a continuous flow process. PubMed van den Broek, Bas A M W; Becker, René; Kössl, Florian; Delville, Mariëlle M E; Nieuwland, Pieter J; Koch, Kaspar; Rutjes, Floris P J T 2012-02-13 Epoxidation of both terminal and non-terminal olefins with peroxy acids is a well-established and powerful tool in a wide variety of chemical processes. In an additional step, the epoxide can be readily converted into the corresponding trans-diol. Batch-wise scale-up, however, is often troublesome because of the thermal instability and explosive character of the peroxy acids involved. This article describes the design and semi-automated optimization of a continuous flow process and subsequent scale-up to preparative production volumes in an intrinsically safe manner. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
7. Refining of plant oils to chemicals by olefin metathesis. PubMed Chikkali, Samir; Mecking, Stefan 2012-06-11 Plant oils are attractive substrates for the chemical industry. Their scope for the production of chemicals can be expanded by sophisticated catalytic conversions. Olefin metathesis is an example, which also illustrates generic issues of "biorefining" to chemicals. Utilization on a large scale requires high catalyst activities, which influences the choice of the metathesis reaction. The mixture of different fatty acids composing a technical-grade plant oil substrate gives rise to a range of products. This decisively determines possible process schemes, and potentially provides novel chemicals and intermediates not employed to date. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
8. Ruthenium indenylidene “1st generation” olefin metathesis catalysts containing triisopropyl phosphite PubMed Central Guidone, Stefano; Nahra, Fady; Slawin, Alexandra M Z 2015-01-01 Summary The reaction of triisopropyl phosphite with phosphine-based indenylidene pre-catalysts affords “1st generation” cis-complexes. These have been used in olefin metathesis reactions. The cis-Ru species exhibit noticeable differences with the trans-Ru parent complexes in terms of structure, thermal stability and reactivity. Experimental data underline the importance of synergistic effects between phosphites and L-type ligands. PMID:26425210
9. Olefins and chemical regulation in Europe: REACH. PubMed Penman, Mike; Banton, Marcy; Erler, Steffen; Moore, Nigel; Semmler, Klaus 2015-11-05 REACH [Registration, Evaluation, Authorisation and Restriction of Chemicals] is the European Union's chemical regulation for the management of risk to human health and the environment [European Chemicals Agency, 2006]. This regulation entered into force in June 2007 and required manufacturers and importers to register substances produced in annual quantities of 1000 tonnes or more by December 2010, with further deadlines for lower tonnages in 2013 and 2018. Depending on the type of registration, required information included the substance's identification, the hazards of the substance, the potential exposure arising from the manufacture or import, the identified uses of the substance, and the operational conditions and risk management measures applied or recommended to downstream users. Among the content developed to support this information were Derived No-Effect Levels or Derived Minimal Effect Levels [DNELs/DMELs] for human health hazard assessment, Predicted No Effect Concentrations [PNECs] for environmental hazard assessment, and exposure scenarios for exposure and risk assessment. Once registered, substances may undergo evaluation by the European Chemicals Agency [ECHA] or Member State authorities and be subject to requests for additional information or testing as well as additional risk reduction measures. To manage the REACH registration and related activities for the European olefins and aromatics industry, the Lower Olefins and Aromatics REACH Consortium was formed in 2008 with administrative and technical support provided by Penman Consulting. A total of 135 substances are managed by this group including 26 individual chemical registrations [e.g. benzene, 1,3-butadiene] and 13 categories consisting of 5-26 substances. This presentation will describe the content of selected registrations prepared for 2010 in addition to the significant post-2010 activities. Beyond REACH, content of the registrations may also be relevant to other European activities, for
10. Organosilicon Compounds and Organosilicon Polymer Intermediates DTIC Science & Technology 1983-03-21 ADDRESS 10. PROGRAM ELEME%- PRO.;ECT. TASK[ Departnknt of Chemistry AREA 6 *OR[ UNI’ N . MBERS Massachusetts Institute of Technology 61102F 2303/B...based on the carbon monoxide-derived acyllithium reagents has been developed. The hydrolysis of dichlorosilane, was found to give cyclic oligomers, with n ...lower members [R=Ph, n =2-5] could be isolated as Ph H 0 n 3 pure species by HPLC. A polymer of molecular weight 蕰,000 was prepared by reaction of l
11. ULTRASOUND-ASSISTED EPOXIDATION OF OLEFINS AND A,B-UNSATURATED KETONES OVER HYDROTALCITES USING HYDROGEN PEROXIDE EPA Science Inventory An efficient ultrasound-assisted epoxidation of olefins and a,B-unsaturated ketones over hydrotacite catalysts in the presence of hydrogen peroxide and acetonitrile is described. This general and selective protocol is relatively fast and is applicable to a wide variety of substra...
12. Polymer-Coated Graphene Aerogel Beads and Supercapacitor Application. PubMed Ouyang, An; Cao, Anyuan; Hu, Song; Li, Yanhui; Xu, Ruiqiao; Wei, Jinquan; Zhu, Hongwei; Wu, Dehai 2016-05-04 Graphene aerogels are highly porous materials with many energy and environmental applications; tailoring the structure and composition of pore walls within the aerogel is the key to those applications. Here, by freeze casting the graphene oxide sheets, we directly fabricated freestanding porous graphene beads containing radially oriented through channels from the sphere center to its surface. Furthermore, we introduced pseudopolymer to make reinforced, functional composite beads with a unique pore morphology. We showed that polymer layers can be coated smoothly on both sides of the pore walls, as well as on the junctions between adjacent pores, resulting in uniform polymer-graphene-polymer sandwiched structures [skeletons] throughout the bead. These composite beads significantly improved the electrochemical properties, with specific capacitances up to 669 F/g and good cyclic stability. Our results indicate that controlled fabrication of homogeneous hierarchical structures is a potential route toward high performance composite electrodes for various energy applications.
13. Cobalt-Iron-Manganese Catalysts for the Conversion of End-of-Life-Tire-Derived Syngas into Light Terminal Olefins. PubMed Falkenhagen, Jan P; Maisonneuve, Lise; Paalanen, Pasi P; Coste, Nathalie; Malicki, Nicolas; Weckhuysen, Bert M 2018-03-26 Co-Fe-Mn/γ-Al 2 O 3 Fischer-Tropsch synthesis [FTS] catalysts were synthesized, characterized and tested for CO hydrogenation, mimicking end-of-life-tire [ELT]-derived syngas. It was found that an increase of C 2 -C 4 olefin selectivities to 49 % could be reached for 5 wt % Co, 5 wt % Fe, 2.5 wt % Mn/γ-Al 2 O 3 with Na at ambient pressure. Furthermore, by using a 5 wt % Co, 5 wt % Fe, 2.5 wt % Mn, 1.2 wt % Na, 0.03 wt % S/γ-Al 2 O 3 catalyst the selectivity towards the fractions of C 5+ and CH 4 could be reduced, whereas the selectivity towards the fraction of C 4 olefins could be improved to 12.6 % at 10 bar. Moreover, the Na/S ratio influences the ratio of terminal to internal olefins observed as products, that is, a high Na loading prevents the isomerization of primary olefins, which is unwanted if 1,3-butadiene is the target product. Thus, by fine-tuning the addition of promoter elements the volume of waste streams that need to be recycled, treated or upgraded during ELT syngas processing could be reduced. The most promising catalyst [5 wt % Co, 5 wt % Fe, 2.5 wt % Mn, 1.2 wt % Na, 0.03 wt % S/γ-Al 2 O 3 ] has been investigated using operando transmission X-ray microscopy [TXM] and X-ray diffraction [XRD]. It was found that a cobalt-iron alloy was formed, whereas manganese remained in its oxidic phase. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.
14. Polymer architectures via mass spectrometry and hyphenated techniques: A review. PubMed Crotty, Sarah; Gerişlioğlu, Selim; Endres, Kevin J; Wesdemiotis, Chrys; Schubert, Ulrich S 2016-08-17 This review covers the application of mass spectrometry [MS] and its hyphenated techniques to synthetic polymers of varying architectural complexities. The synthetic polymers are discussed as according to their architectural complexity from linear homopolymers and copolymers to stars, dendrimers, cyclic copolymers and other polymers. MS and tandem MS [MS/MS] has been extensively used for the analysis of synthetic polymers. However, the increase in structural or architectural complexity can result in analytical challenges that MS or MS/MS cannot overcome alone. Hyphenation to MS with different chromatographic techniques [2D × LC, SEC, HPLC etc.], utilization of other ionization methods [APCI, DESI etc.] and various mass analyzers [FT-ICR, quadrupole, time-of-flight, ion trap etc.] are applied to overcome these challenges and achieve more detailed structural characterizations of complex polymeric systems. In addition, computational methods [software: MassChrom2D, COCONUT, 2D maps etc.] have also reached polymer science to facilitate and accelerate data interpretation. Developments in technology and the comprehension of different polymer classes with diverse architectures have significantly improved, which allow for smart polymer designs to be examined and advanced. We present specific examples covering diverse analytical aspects as well as forthcoming prospects in polymer science. Copyright © 2016 Elsevier B.V. All rights reserved.
15. Catalyst for converting synthesis gas to light olefins DOEpatents Rao, V. Udaya S.; Gormley, Robert J. 1982-01-01 A catalyst and process for making same useful in the catalytic hydrogenation of carbon monoxide in which a silicalite support substantially free of aluminum is soaked in an aqueous solution of iron and potassium salts wherein the iron and potassium are present in concentrations such that the dried silicalite has iron present in the range of from about 5 to about 25 percent by weight and has potassium present in an amount not less than about 0.2 percent by weight, and thereafter the silicalite is dried and combined with amorphous silica as a binder for pellets, the catalytic pellets are used to convert synthesis gas to C.sub.2 -C.sub.4 olefins.
16. Conversion of Syngas-Derived C2+ Mixed Oxygenates to C3-C5 Olefins over ZnxZryOz Mixed Oxides Catalysts DOE Office of Scientific and Technical Information [OSTI.GOV] Smith, Colin D.; Lebarbier, Vanessa M.; Flake, Matthew D. 2016-04-01 In this study we report on a ZnxZryOz mixed oxide type catalyst capable of converting a syngas-derived C2+ mixed oxygenate feedstock to isobutene-rich olefins. Aqueous model feed comprising of ethanol, acetaldehyde, acetic acid, ethyl acetate, methanol, and propanol was used as representative liquid product derived from a Rh-based mixed oxygenate synthesis catalyst. Greater than 50% carbon yield to C3-C5 mixed olefins was demonstrated when operating at 400-450oC and 1 atm. In order to rationalize formation of the products observed feed components were individually evaluated. Major constituents of the feed mixture [ethanol, acetaldehyde, acetic acid, and ethyl acetate] were found tomore » produce isobutene-rich olefins. C-C coupling was also demonstrated for propanol feedstock - a minor constituent of the mixed oxygenate feed - producing branched C6 olefins, revealing scalability to alcohols higher than ethanol following an analogous reaction pathway. Using ethanol and propanol feed mixtures, cross-coupling reactions produced mixtures of C4, C5, and C6 branched olefins. The presence of H2 in the feed was found to facilitate hydrogenation of the ketone intermediates, thus producing straight chain olefins as byproducts. While activity loss from coking is observed complete catalyst regeneration is achieved by employing mild oxidation. For conversion of the mixed oxygenate feed a Zr/Zn ratio of 2.5 and a reaction temperature of 450oC provides the best balance of stability, activity, and selectivity. X-ray diffraction and scanning transmission electron microscopy analysis reveals the presence of primarily cubic phase ZrO2 and a minor amount of the monoclinic phase, with ZnO being highly dispersed in the lattice. The presence of ZnO appears to stabilize the cubic phase resulting in less monoclinic phase as the ZnO concentration increases. Infrared spectroscopy shows the mixed oxide acid sites are characterized as primarily Lewis type acidity. The direct relationship
17. Green polymer chemistry: investigating the mechanism of radical ring-opening redox polymerization [R3P] of 3,6-dioxa-1,8-octanedithiol [DODT]. PubMed Rosenthal-Kim, Emily Q; Puskas, Judit E 2015-04-13 The mechanism of the new Radical Ring-opening Redox Polymerization [R3P] of 3,6-dioxa-1,8-octanedithiol [DODT] by triethylamine [TEA] and dilute H2O2 was investigated. Scouting studies showed that the formation of high molecular weight polymers required a 1:2 molar ratio of DODT to TEA and of DODT to H2O2. Further investigation into the chemical composition of the organic and aqueous phases by 1H-NMR spectroscopy and mass spectrometry demonstrated that DODT is ionized by two TEA molecules [one for each thiol group] and thus transferred into the aqueous phase. The organic phase was found to have cyclic disulfide dimers, trimers and tetramers. Dissolving DODT and TEA in water before the addition of H2O2 yielded a polymer with Mn = 55,000 g/mol, in comparison with Mn = 92,000 g/mol when aqueous H2O2 was added to a DODT/TEA mixture. After polymer removal, MALDI-ToF MS analysis of the residual reaction mixtures showed only cyclic oligomers remaining. Below the LCST for TEA in water, 18.7 °C, the system yielded a stable emulsion, and only cyclic oligomers were found. Below DODT/TEA and H2O2 1:2 molar ratio mostly linear oligomers were formed, with 400 kg/mol] and end-association strength is optimal. Viscometry and scattering measurements of long telechelic polymers having polycyclooctadiene backbones and acid or amine end groups verify the formation of megasupramolecules. They control misting and reduce drag in the same manner as ultralong covalent polymers. With individual building blocks short enough to avoid hydrodynamic chain scission [weight-average molecular weights of 400 to 1000 kg/mol] and reversible linkages that protect covalent bonds, these megasupramolecules overcome the obstacles of shear degradation and engine incompatibility.
18. Affordable Cyclic Voltammetry ERIC Educational Resources Information Center Stewart, Greg; Kuntzleman, Thomas S.; Amend, John R.; Collins, Michael J. 2009-01-01 Cyclic voltammetry is an important component of the undergraduate chemical curriculum. Unfortunately, undergraduate students rarely have the opportunity to conduct experiments in cyclic voltammetry owing to the high cost of potentiostats, which are required to control these experiments. By using MicroLab data acquisition interfaces in conjunction…
19. Chemical and charge transfer studies on interfaces of a conjugated polymer and ITO NASA Astrophysics Data System [ADS] David, Tanya M. S.; Arasho, Wondwosson; Smith, O'Neil; Hong, Kunlun; Bonner, Carl; Sun, Sam-Shajing 2017-08-01 Conjugated oligomers and polymers are very attractive for potential future plastic electronic and opto-electronic device applications such as plastic photo detectors and solar cells, thermoelectric devices, field effect transistors, and light emitting diodes. Understanding and optimizing charge transport between an active polymer layer and conductive substrate is critical to the optimization of polymer based electronic and opto-electronic devices. This study focused on the design, synthesis, self-assembly, and electron transfers and transports of a phosphonic acid end-functionalized polyphenylenevinylene [PPV] that was covalently attached and self-assembled onto an Indium Tin Oxide [ITO] substrate. This study demonstrated how atomic force microscopy [AFM] can be an effective characterization technique in conjunction with conventional electron transfer methods, including cyclic voltammetry [CV], towards determining electron transfer rates in polymer and polymer/conductor interface systems. This study found that the electron transfer rates of covalently attached and self-assembled films were much faster than the spin coated films. The knowledge from this study can be very useful for designing potential polymer based electronic and opto-electronic thin film devices.
20. Palladium-catalyzed stereoretentive olefination of unactivated C[sp3]-H bonds with vinyl iodides at room temperature: synthesis of β-vinyl α-amino acids. PubMed Wang, Bo; Lu, Chengxi; Zhang, Shu-Yu; He, Gang; Nack, William A; Chen, Gong 2014-12-05 A method is reported for palladium-catalyzed N-quinolyl carboxamide-directed olefination of the unactivated C[sp[3]]-H bonds of phthaloyl alanine with a broad range of vinyl iodides at room temperature. This reaction represents the first example of the stereoretentive installation of multisubstituted terminal and internal olefins onto unactivated C[sp[3]]-H bonds. These methods enable access to a wide range of challenging β-vinyl α-amino acid products in a streamlined and controllable fashion, beginning from simple precursors.
21. Switching Cyclic Nucleotide-Selective Activation of Cyclic Adenosine Monophosphate-Dependent Protein Kinase Holoenzyme Reveals Distinct Roles of Tandem Cyclic Nucleotide-Binding Domains. PubMed He, Daniel; Lorenz, Robin; Kim, Choel; Herberg, Friedrich W; Lim, Chinten James 2017-12-15 The cyclic adenosine monophosphate [cAMP]- and cyclic guanosine monophosphate [cGMP]-dependent protein kinases [PKA and PKG] are key effectors of cyclic nucleotide signaling. Both share structural features that include tandem cyclic nucleotide-binding [CNB] domains, CNB-A and CNB-B, yet their functions are separated through preferential activation by either cAMP or cGMP. Based on structural studies and modeling, key CNB contact residues have been identified for both kinases. In this study, we explored the requirements for conversion of PKA activation from cAMP-dependent to cGMP-dependent. The consequences of the residue substitutions T192R/A212T within CNB-A or G316R/A336T within CNB-B of PKA-RIα on cyclic nucleotide binding and holoenzyme activation were assessed in vitro using purified recombinant proteins, and ex vivo using RIα-deficient mouse embryonic fibroblasts genetically reconstituted with wild-type or mutant PKA-RIα. In vitro, a loss of binding and activation selectivity was observed when residues in either one of the CNB domains were mutated, while mutations in both CNB domains resulted in a complete switch of selectivity from cAMP to cGMP. The switch in selectivity was also recapitulated ex vivo, confirming their functional roles in cells. Our results highlight the importance of key cyclic nucleotide contacts within each CNB domain and suggest that these domains may have evolved from an ancestral gene product to yield two distinct cyclic nucleotide-dependent protein kinases.
22. Highly Flexible and Planar Supercapacitors Using Graphite Flakes/Polypyrrole in Polymer Lapping Film. PubMed Raj, C Justin; Kim, Byung Chul; Cho, Won-Je; Lee, Won-gil; Jung, Sang-Don; Kim, Yong Hee; Park, Sang Yeop; Yu, Kook Hyun 2015-06-24 Flexible supercapacitor electrodes have been fabricated by simple fabrication technique using graphite nanoflakes on polymer lapping films as flexible substrate. An additional thin layer of conducting polymer polypyrrole over the electrode improved the surface conductivity and exhibited excellent electrochemical performances. Such capacitor films showed better energy density and power density with a maximum capacitance value of 37 mF cm[-2] in a half cell configuration using 1 M H2SO4 electrolyte, 23 mF cm[-2] in full cell, and 6 mF cm[-2] as planar cell configuration using poly[vinyl alcohol] [PVA]/phosphoric acid [H3PO4] solid state electrolyte. Moreover, the graphite nanoflakes/polypyrrole over polymer lapping film demonstrated good flexibility and cyclic stability.
23. Tandem isomerization-decarboxylation of unsaturated fatty acids to olefins via ruthenium metal-as-ligand catalysts USDA-ARS?s Scientific Manuscript database A new facile Ru-catalyzed route to bio-olefins3 from unsaturated fatty acids via readily accessible metal-as-ligand type catalyst precursors, [Ru[CO]2RCO2]n and Ru3[CO]12, will be described. The catalyst apparently functions in a tandem mode by dynamically isomerizing the positions of double bonds i...

1. Cyclization Phenomena in the Sol-Gel Polymerization of a,w-Bis[triethoxysilyl]alkanes and Incorporation of the Cyclic Structures into Network Silsesquioxane Polymers DOE Office of Scientific and Technical Information [OSTI.GOV] Alam, T.M.; Carpenter, J.P.; Dorhout, P.K. 1999-01-04 Intramolecular cyclizations during acid-catalyzed, sol-gel polymerizations of ct,co- bis[tietioxysilyl]aWmes substintidly lengtien gelties formonomers witietiylene- [l], propylene- [2], and butylene-[3]-bridging groups. These cyclizations reactions were found, using mass spectrometry and %i NMR spectroscopy, to lead preferentially to monomeric and dimeric products based on six and seven membered disilsesquioxane rings. 1,2- Bis[triethoxysilyl]ethane [1] reacts under acidic conditions to give a bicyclic drier [5] that is composed of two annelated seven membered rings. Under the same conditions, 1,3- bis[triethoxysilyl]propane [2], 1,4-bis[triethoxysilyl]butane [3], and z-1,4- bis[triethoxysilyl]but-2-ene [10] undergo an intramolecular condensation reaction to give the six membemd and seven membered cyclic disilsesquioxanes 6, 7,more » and 11. Subsequently, these cyclic monomers slowly react to form the tricyclic dirners 8,9 and 12. With NaOH as polymerization catalyst these cyclic silsesquioxanes readily ~aeted to afford gels that were shown by CP MAS z%i NMR and infr=d spectroscopes to retain some cyclic structures. Comparison of the porosity and microstructwe of xerogels prepared from the cyclic monomers 6 and 7 with gels prepared directly from their acyclic precursors 2 and 3, indicate that the final pore structure of the xerogels is markedly dependent on the nature of the precursor. In addition, despite the fact that the monomeric cyclic disilsesquioxane species can not be isolated from 1-3 under basic conditions due to their rapid rate of gelation, spectroscopic techniques also detected the presence of the cyclic structures in the resulting polymeric gels.« less
2. Investigation of Expandable Polymeric Microspheres for Packaging Applications DTIC Science & Technology 2012-06-06 FILMS COST REDUCTION OLEFIN POLYMERS COSTS PACKAGING MICROSPHERES WASTE DISPOSAL WEIGHT...MANAGEMENT THERMAL INSULATION DENSITY SOLID WASTES ENVIRONMENTAL IMPACT THERMOPLASTIC POLYMERS POLYMERS ...research. The purpose was to provide information on the incorporation of hollow, expandable polymeric microspheres into thermoplastic polymers to
3. Conjugated polymer energy level shifts in lithium-ion battery electrolytes. PubMed Song, Charles Kiseok; Eckstein, Brian J; Tam, Teck Lip Dexter; Trahey, Lynn; Marks, Tobin J 2014-11-12 The ionization potentials [IPs] and electron affinities [EAs] of widely used conjugated polymers are evaluated by cyclic voltammetry [CV] in conventional electrochemical and lithium-ion battery media, and also by ultraviolet photoelectron spectroscopy [UPS] in vacuo. By comparing the data obtained in the different systems, it is found that the IPs of the conjugated polymer films determined by conventional CV [IPC] can be correlated with UPS-measured HOMO energy levels [EH,UPS] by the relationship EH,UPS = [1.14 ± 0.23] × qIPC + [4.62 ± 0.10] eV, where q is the electron charge. It is also found that the EAs of the conjugated polymer films measured via CV in conventional [EAC] and Li[+] battery [EAB] media can be linearly correlated by the relationship EAB = [1.07 ± 0.13] × EAC + [2.84 ± 0.22] V. The slopes and intercepts of these equations can be correlated with the dielectric constants of the polymer film environments and the redox potentials of the reference electrodes, as modified by the surrounding electrolyte, respectively.
4. Crystal Structure and Catalytic Behavior in Olefin Epoxidation of a One-Dimensional Tungsten Oxide/Bipyridine Hybrid. PubMed Amarante, Tatiana R; Antunes, Margarida M; Valente, Anabela A; Paz, Filipe A Almeida; Pillinger, Martyn; Gonçalves, Isabel S 2015-10-19 The tungsten oxide/2,2'-bipyridine hybrid material [WO3[2,2'-bpy]]·nH2O [n = 1-2] [1] has been prepared in near quantitative yield by the reaction of H2WO4, 2,2'-bpy, and H2O in the mole ratio of ca. 1:2:700 at 160 °C for 98 h in a rotating Teflon-lined digestion bomb. The solid-state structure of 1 was solved and refined through Rietveld analysis of high-resolution synchrotron X-ray diffraction data collected for the microcrystalline powder. The material, crystallizing in the orthorhombic space group Iba2, is composed of a one-dimensional organic-inorganic hybrid polymer, ∞[1][WO3[2,2'-bpy]], topologically identical to that found in the previously reported anhydrous phases [MO3[2,2'-bpy]] [M = Mo, W]. While in the latter the N,N'-chelated 2,2'-bpy ligands of adjacent corner-shared {MO4N2} octahedra are positioned on the same side of the 1D chain, in 1 the 2,2'-bpy ligands alternate above and below the chain. The catalytic behavior of compound 1 for the epoxidation of cis-cyclooctene was compared with that for several other tungsten- or molybdenum-based [pre]catalysts, including the hybrid polymer [MoO3[2,2'-bpy]]. While the latter exhibits superior performance when tert-butyl hydroperoxide [TBHP] is used as the oxidant, compound 1 is superior when aqueous hydrogen peroxide is used, allowing near-quantitative conversion of the olefin to the epoxide. With H2O2, compounds 1 and [MoO3[2,2'-bpy]] act as sources of soluble active species, namely, the oxodiperoxo complex [MO[O2]2[2,2'-bpy]], which is formed in situ. Compounds 1 and [WO[O2]2[2,2'-bpy]] [2] were further tested in the epoxidation of cyclododecene, trans-2-octene, 1-octene, [R]-limonene, and styrene. The structure of 2 was determined by single-crystal X-ray diffraction and found to be isotypical with the molybdenum analogue.
5. Poly[ethylene glycol]-grafted cyclic acetals based polymer networks with non-water-swellable, biodegradable and surface hydrophilic properties. PubMed Yin, Ruixue; Zhang, Nan; Wu, Wentao; Wang, Kemin 2016-05-01 Cyclic acetals based biomaterial without acidic products during hydrolytic degradation is a promising candidate for tissue engineering applications; however, low hydrophilicity is still one limitation for its biomedical application. In this work, we aim to achieve non-water-swellable cyclic acetal networks with improved hydrophilicity and surface wettability by copolymerization of cyclic acetal units based monomer, 5-ethyl-5-[hydroxymethyl]-β,β-dimethyl-1, 3-dioxane-2-ethanol diacrylate [EHD] and methoxy poly[ethylene glycol] monoacrylate [mPEGA] under UV irradiation, to avoid swelling of conventional hydrogels which could limit their applicability in particular of the mechanical properties and geometry integrity. Various EHD/mPEGA networks were fabricated with different concentrations of mPEGA from 0 to 30%, and the results showed photopolymerization behavior, mechanical property and thermal stability could not be significantly affected by addition of mPEGA, while the surface hydrophilicity was dramatically improved with the increase of mPEGA and could achieve a water contact angle of 37° with 30% mPEGA concentration. The obtained EHD/mPEGA network had comparative degradation rate to the PECA hydrogels reported previously, and MTT assay indicated it was biocompatible to L929 cells. Copyright © 2016 Elsevier B.V. All rights reserved.
6. Green polymer chemistry: Synthesis of poly[disulfide] polymers and networks NASA Astrophysics Data System [ADS] Rosenthal-Kim, Emily Quinn distribution of around 1.15. However, the majority of the product consists of low molecular weight cyclic poly[disulfide] oligomers. In reactions maintained below 18°C, the organic components were miscible in the aqueous hydrogen peroxide and a milky emulsion was produced. The polymers were degraded using the disulfide-specific reducing agent, dithiothreitol. Poly[disulfide] polymer networks were also synthesized in a two-phase system. Due to the poor solubility of the crosslinker, trimethylolpropane tris[2-mercaptopropionate, organic solvents were required to obtain consistent networks. The networks were degraded using dithiothreitol in tetrahydrofuran. The networks were stable under aqueous reducing conditions. The disulfide-bearing biochemical, alpha-lipoic acid, was investigated as monomer for the new method of poly[disulfide] polymer synthesis. It was also polymerized thermally and by a new interfacial method that proceeds at the air-water interface. Polymer products were often too large to be characterized by SEC [Mn > 1,000,000 g/mol]. A poly[alpha-LA] polymer sample showed mass loss in aqueous solutions of glutathione at pH = 5.2 which was used to model cytosolic conditions. Poly[alpha-LA] was decorated with PEG [2,000 g/mol] in an esterification reaction catalyzed by Candida antarctica lipase B [CALB]. The decorated polymers were imaged using AFM which revealed branch-like structures. To make new alpha-lipoic acid based monomers and macromonomers, CALB-catalyzed esterification, was used to conjugate alpha-lipoic acid to a variety of glycols including: diethylene glycol monomethyl ether, tetraethylene glycol, hexaethylene glycol, and poly[ethylene glycol]. The products were verified using NMR spectroscopy and mass spectrometry.
7. Visual search of cyclic spatio-temporal events NASA Astrophysics Data System [ADS] Gautier, Jacques; Davoine, Paule-Annick; Cunty, Claire 2018-05-01 The analysis of spatio-temporal events, and especially of relationships between their different dimensions [space-time-thematic attributes], can be done with geovisualization interfaces. But few geovisualization tools integrate the cyclic dimension of spatio-temporal event series [natural events or social events]. Time Coil and Time Wave diagrams represent both the linear time and the cyclic time. By introducing a cyclic temporal scale, these diagrams may highlight the cyclic characteristics of spatio-temporal events. However, the settable cyclic temporal scales are limited to usual durations like days or months. Because of that, these diagrams cannot be used to visualize cyclic events, which reappear with an unusual period, and don't allow to make a visual search of cyclic events. Also, they don't give the possibility to identify the relationships between the cyclic behavior of the events and their spatial features, and more especially to identify localised cyclic events. The lack of possibilities to represent the cyclic time, outside of the temporal diagram of multi-view geovisualization interfaces, limits the analysis of relationships between the cyclic reappearance of events and their other dimensions. In this paper, we propose a method and a geovisualization tool, based on the extension of Time Coil and Time Wave, to provide a visual search of cyclic events, by allowing to set any possible duration to the diagram's cyclic temporal scale. We also propose a symbology approach to push the representation of the cyclic time into the map, in order to improve the analysis of relationships between space and the cyclic behavior of events.
8. Megasupramolecules for safer, cleaner fuel by end association of long telechelic polymers. PubMed Wei, Ming-Hsin; Li, Boyu; David, R L Ameri; Jones, Simon C; Sarohia, Virendra; Schmitigal, Joel A; Kornfield, Julia A 2015-10-02 We used statistical mechanics to design polymers that defy conventional wisdom by self-assembling into "megasupramolecules" [≥5000 kg/mol] at low concentration [≤0.3 weight percent]. Theoretical treatment of the distribution of individual subunits—end-functional polymers—among cyclic and linear supramolecules [ring-chain equilibrium] predicts that megasupramolecules can form at low total polymer concentration if, and only if, the backbones are long [>400 kg/mol] and end-association strength is optimal. Viscometry and scattering measurements of long telechelic polymers having polycyclooctadiene backbones and acid or amine end groups verify the formation of megasupramolecules. They control misting and reduce drag in the same manner as ultralong covalent polymers. With individual building blocks short enough to avoid hydrodynamic chain scission [weight-average molecular weights of 400 to 1000 kg/mol] and reversible linkages that protect covalent bonds, these megasupramolecules overcome the obstacles of shear degradation and engine incompatibility. Copyright © 2015, American Association for the Advancement of Science.
9. 3D printed sensing patches with embedded polymer optical fibre Bragg gratings NASA Astrophysics Data System [ADS] Zubel, Michal G.; Sugden, Kate; Saez-Rodriguez, D.; Nielsen, K.; Bang, O. 2016-05-01 The first demonstration of a polymer optical fibre Bragg grating [POFBG] embedded in a 3-D printed structure is reported. Its cyclic strain performance and temperature characteristics are examined and discussed. The sensing patch has a repeatable strain sensitivity of 0.38 pm/μepsilon. Its temperature behaviour is unstable, with temperature sensitivity values varying between 30-40 pm/°C.
10. Cyclic-β-glucans of Rhizobium [Sinorhizobium] sp. strain NGR234 are required for hypo-osmotic adaptation, motility, and efficient symbiosis with host plants. PubMed Gay-Fraret, Jérémie; Ardissone, Silvia; Kambara, Kumiko; Broughton, William J; Deakin, William J; Le Quéré, Antoine 2012-08-01 Cyclic-β-glucans [CβG] consist of cyclic homo-polymers of glucose that are present in the periplasmic space of many Gram-negative bacteria. A number of studies have demonstrated their importance for bacterial infection of plant and animal cells. In this study, a mutant of Rhizobium [Sinorhizobium] sp. strain NGR234 [NGR234] was generated in the cyclic glucan synthase [ndvB]-encoding gene. The great majority of CβG produced by wild-type NGR234 are negatively charged and substituted. The ndvB mutation abolished CβG biosynthesis. We found that, in NGR234, a functional ndvB gene is essential for hypo-osmotic adaptation and swimming, attachment to the roots, and efficient infection of Vigna unguiculata and Leucaena leucocephala. © 2012 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.
11. Cyclic nucleotide content of tobacco BY-2 cells. PubMed Richards, Helen; Das, Swadipa; Smith, Christopher J; Pereira, Louisa; Geisbrecht, Alan; Devitt, Nicola J; Games, David E; van Geyschem, Jan; Gareth Brenton, A; Newton, Russell P 2002-11-01 The cyclic nucleotide content of cultured tobacco bright yellow-2 [BY-2] cells was determined, after freeze-killing, perchlorate extraction and sequential chromatography, by radioimmunoassay. The identities of the putative cyclic nucleotides, adenosine 3',5'-cyclic monophosphate [cyclic AMP], guanosine 3',5'-cyclic monophosphate [cyclic GMP] and cytidine 3',5'-cyclic monophosphate [cyclic CMP] were unambiguously confirmed by tandem mass spectrometry. The potential of BY-2 cell cultures as a model system for future investigations of cyclic nucleotide function in higher plants is discussed.
12. Olefin Epoxidation by Methyltrioxorhenium: A Density Functional Study on Energetics and Mechanisms. PubMed Gisdakis, Philip; Antonczak, Serge; Köstlmeier, Sibylle; Herrmann, Wolfgang A; Rösch, Notker 1998-09-04 A spiro attack on a peroxo group is calculated to be the preferred reaction pathway for olefin epoxidation with the catalytic system CH 3 ReO 3 /H 2 O 2 [see picture]. This finding is supported by density functional calculations on more than ten transition states for the most probable mechanisms. Hydration has significant effects on various reaction species: it stabilizes the intermediates and destabilizes, with one exception, the transition states. © 1998 WILEY-VCH Verlag GmbH, Weinheim, Fed. Rep. of Germany.
13. Advances in targeting cyclic nucleotide phosphodiesterases PubMed Central Maurice, Donald H.; Ke, Hengming; Ahmad, Faiyaz; Wang, Yousheng; Chung, Jay; Manganiello, Vincent C. 2014-01-01 Cyclic nucleotide phosphodiesterases [PDEs] catalyse the hydrolysis of cyclic AMP and cyclic GMP, thereby regulating the intracellular concentrations of these cyclic nucleotides, their signalling pathways and, consequently, myriad biological responses in health and disease. Currently, a small number of PDE inhibitors are used clinically for treating the pathophysiological dysregulation of cyclic nucleotide signalling in several disorders, including erectile dysfunction, pulmonary hypertension, acute refractory cardiac failure, intermittent claudication and chronic obstructive pulmonary disease. However, pharmaceutical interest in PDEs has been reignited by the increasing understanding of the roles of individual PDEs in regulating the subcellular compartmentalization of specific cyclic nucleotide signalling pathways, by the structure-based design of novel specific inhibitors and by the development of more sophisticated strategies to target individual PDE variants. PMID:24687066
14. 21 CFR 175.320 - Resinous and polymeric coatings for polyolefin films. Code of Federal Regulations, 2014 CFR 2014-04-01 ... film over one or both sides of a base film produced from one or more of the basic olefin polymers complying with § 177.1520 of this chapter. The base polyolefin film may contain optional adjuvant substances... Limitations [i] Resins and polymers: Acrylic acid polymer and its ethyl or methyl esters Acrylamide...
15. Equilibrium polymerization of cyclic carbonate oligomers. III. Chain branching and the gel transition NASA Astrophysics Data System [ADS] Ballone, P.; Jones, R. O. 2002-10-01 Ring-opening polymerization of cyclic polycarbonate oligomers, where monofunctional active sites act on difunctional monomers to produce an equilibrium distribution of rings and chains, leads to a "living polymer." Monte Carlo simulations [two-dimensional [2D] and three-dimensional [3D]] of the effects of single [J. Chem. Phys. 115, 3895 [2001]] and multiple active sites [J. Chem. Phys. 116, 7724 [2002]] are extended here to trifunctional active sites that lead to branching. Low concentrations of trifunctional particles c3 reduce the degree of polymerization significantly in 2D, and higher concentrations [up to 32%] lead to further large changes in the phase diagram. Gel formation is observed at high total density and sizable c3 as a continuous transition similar to percolation. Polymer and gel are much more stable in 3D than in 2D, and both the total density and the value of c3 required to produce high molecular weight aggregates are reduced significantly. The degree of polymerization in high-density 3D systems is increased by the addition of trifunctional monomers and reduced slightly at low densities and low c3. The presence of branching makes equilibrium states more sensitive [in 2D and 3D] to changes in temperature T. The stabilities of polymer and gel are enhanced by increasing T, and—for sufficiently high values of c3—there is a reversible polymer-gel transformation at a density-dependent floor temperature.
16. Novel polyoxometalate silica nano-sized spheres: efficient catalysts for olefin oxidation and the deep desulfurization process. PubMed Nogueira, Lucie S; Ribeiro, Susana; Granadeiro, Carlos M; Pereira, Eulália; Feio, Gabriel; Cunha-Silva, Luís; Balula, Salete S 2014-07-07 A novel method to prepare silica nano-sized particles incorporating polyoxometalates was developed leading to a new efficient heterogeneous oxidative catalyst. Zinc-substituted polyoxotungstate [PW11Zn[H2O]O39][5-] [PW11Zn] was encapsulated into silica nanoparticles using a cross-linked organic-inorganic core, performed through successive spontaneous reactions in water. The potassium salt of PW11Zn and the composite formed, PW11Zn-APTES@SiO2, were characterized by a myriad of solid-state methods such as FT-IR, FT-Raman, [31]P and [13]C CP/MAS solid-state NMR, elemental analysis and SEM-EDS, confirming the integrity of the PW11Zn structure immobilized in the silica nanoparticles. The new composite has shown to be a versatile catalyst for the oxidation of olefins and also to catalyze the desulfurization of a model oil using H2O2 as the oxidant and acetonitrile as the solvent. The novel composite material was capable of being recycled without significant loss of activity and maintaining its structural stability for consecutive desulfurization and olefin oxidative cycles.
17. Effect of Feedstock and Catalyst Impurities on the Methanol‐to‐Olefin Reaction over H‐SAPO‐34 PubMed Central Vogt, Charlotte; Ruiz‐Martínez, Javier 2016-01-01 Abstract Operando UV/Vis spectroscopy with on‐line mass spectrometry was used to study the effect of different types of impurities on the hydrocarbon pool species and the activity of H‐SAPO‐34 as a methanol‐to‐olefins [MTO] catalyst. Successive reaction cycles with different purity feedstocks were studied, with an intermittent regeneration step. The combined study of two distinct impurity types [i.e., feed and internal impurities] leads to new insights into MTO catalyst activation and deactivation mechanisms. In the presence of low amounts of feed impurities, the induction and active periods of the process are prolonged. Feed impurities are thus beneficial in the formation of the initial hydrocarbon pool, but also aid in the unwanted formation of deactivating coke species by a separate, competing mechanism favoring coke species over olefins. Further, feedstock impurities strongly influence the location of coke deposits, and thus influence the deactivation mechanism, whereas a study of the organic impurities retained after calcination reveals that these species are less relevant for catalyst activity and function as “seeds” for coke formation only. PMID:28163792
18. Brownian dynamics of wall tethered polymers in shear flow NASA Astrophysics Data System [ADS] Lin, Tiras Y.; Saadat, Amir; Kushwaha, Amit; Shaqfeh, Eric S. G. 2017-11-01 The dynamics of a wall tethered polymer in shear flow is studied using Brownian dynamics. Simulations are performed with bead-spring chains, and the effect of hydrodynamic interactions [HI] is incorporated through Blake's tensor with a finite size bead correction. We characterize the configuration of the polymer as a function of the Weissenberg number by investigating the regions the polymer explores in both the flow-gradient and flow-vorticity planes. The fractional extension in the flow direction, the width in the vorticity direction, and the thickness in the gradient direction are reported as well, and these quantities are found to compare favorably with the experimental data of the literature. The cyclic motion of the polymer is demonstrated through analysis of the mean velocity field of the end bead. We characterize the collision process of each bead with the wall as a Poisson process and extract an average wall collision rate, which in general varies along the backbone of the chain. The inclusion of HI with the wall for a tethered polymer is found to reduce the average wall collision rate. We anticipate that results from this work will be directly applicable to, e.g., the design of polymer brushes or the use of DNA for making nanowires in molecular electronics. T.Y.L. is supported by the Department of Defense [DoD] through the National Defense Science & Engineering Graduate Fellowship [NDSEG] Program.
19. Imidazolium salt-modified porous hypercrosslinked polymers for synergistic CO2 capture and conversion. PubMed Wang, Jinquan; Sng, Waihong; Yi, Guangshun; Zhang, Yugen 2015-08-04 A new type of imidazolium salt-modified porous hypercrosslinked polymer [BET surface area up to 926 m[2] g[-1]] was reported. These porous materials exhibited good CO2 capture capacities [14.5 wt%] and catalytic activities for the conversion of CO2 into various cyclic carbonates under metal-free conditions. The synergistic effect of CO2 capture and conversion was observed.
20. Process and catalyst for carbonylating olefins DOEpatents Zoeller, Joseph Robert 1998-06-02 Disclosed is an improved catalyst system and process for preparing aliphatic carbonyl compounds such as aliphatic carboxylic acids, alkyl esters of aliphatic carboxylic acids and anhydrides of aliphatic carboxylic acids by carbonylating olefins in the presence of a catalyst system comprising [1] a first component selected from at least one Group 6 metal, i.e., chromium, molybdenum, and/or tungsten and [2] a second component selected from at least one of certain halides and tertiary and quaternary compounds of a Group 15 element, i.e., nitrogen, phosphorus and/or arsenic, and [3] as a third component, a polar, aprotic solvent. The process employing the improved catalyst system is carried out under carbonylating conditions of pressure and temperature discussed herein. The process constitutes and improvement over known processes since it can be carried out at moderate carbonylation conditions without the necessity of using an expensive noble metal catalyst, volatile, toxic materials such as nickel tetracarbonyl, formic acid or a formate ester. Further, the addition of a polar, aprotic solvent to the catalyst system significantly increases, or accelerates, the rate at which the carbonylation takes place.

1. An adaptive self-healing ionic liquid nanocomposite membrane for olefin-paraffin separations. PubMed Pitsch, Fee; Krull, Florian F; Agel, Friederike; Schulz, Peter; Wasserscheid, Peter; Melin, Thomas; Wessling, Matthias 2012-08-16 An adaptive self-healing ionic liquid nanocomposite membrane comprising a multi-layer support structure hosting the ionic salt [Ag][+] [Tf[2] N][-] is used for the separation of the olefin propylene and the paraffin propane. The ionic salt renders liquid like upon complexation with propylene, resulting in facilitated transport of propylene over propane at benchmark-setting selectivity and permeance levels. The contacting with acetylene causes the ionic salt to liquefy without showing evidence of forming explosive silver acetylide. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
2. Iron-catalyzed olefin epoxidation in the presence of acetic acid: insights into the nature of the metal-based oxidant. PubMed Mas-Ballesté, Rubén; Que, Lawrence 2007-12-26 The iron complexes [[BPMEN]Fe[OTf]2] [1] and [[TPA]Fe[OTf]2] [2] [BPMEN = N,N'-bis-[2-pyridylmethyl]-N,N'-dimethyl-1,2-ethylenediamine; TPA = tris-[2-pyridylmethyl]amine] catalyze the oxidation of olefins by H2O2 to yield epoxides and cis-diols. The addition of acetic acid inhibits olefin cis-dihydroxylation and enhances epoxidation for both 1 and 2. Reactions carried out at 0 degrees C with 0.5 mol % catalyst and a 1:1.5 olefin/H2O2 ratio in a 1:2 CH3CN/CH3COOH solvent mixture result in nearly quantitative conversions of cyclooctene to epoxide within 1 min. The nature of the active species formed in the presence of acetic acid has been probed at low temperature. For 2, in the absence of substrate, [[TPA]FeIII[OOH][CH3COOH]]2+ and [[TPA]FeIVO[NCCH3]]2+ intermediates can be observed. However, neither is the active epoxidizing species. In fact, [[TPA]FeIVO[NCCH3]]2+ is shown to form in competition with substrate oxidation. Consequently, it is proposed that epoxidation is mediated by [[TPA]FeV[O][OOCCH3]]2+, generated from O-O bond heterolysis of the [[TPA]FeIII[OOH][CH3COOH]]2+ intermediate, which is promoted by the protonation of the terminal oxygen atom of the hydroperoxide by the coordinated carboxylic acid.
3. Comparing the cyclic behavior of concrete cylinders confined by shape memory alloy wire or steel jackets NASA Astrophysics Data System [ADS] Park, Joonam; Choi, Eunsoo; Park, Kyoungsoo; Kim, Hong-Taek 2011-09-01 Shape memory alloy [SMA] wire jackets for concrete are distinct from conventional jackets of steel or fiber reinforced polymer [FRP] since they provide active confinement which can be easily achieved due to the shape memory effect of SMAs. This study uses NiTiNb SMA wires of 1.0 mm diameter to confine concrete cylinders with the dimensions of 300 mm × 150 mm [L × D]. The NiTiNb SMAs have a relatively wider temperature hysteresis than NiTi SMAs; thus, they are more suitable for the severe temperature-variation environments to which civil structures are exposed. Steel jackets of passive confinement are also prepared in order to compare the cyclic behavior of actively and passively confined concrete cylinders. For this purpose, monotonic and cyclic compressive loading tests are conducted to obtain axial and circumferential strain. Both strains are used to estimate the volumetric strains of concrete cylinders. Plastic strains from cyclic behavior are also estimated. For the cylinders jacketed by NiTiNb SMA wires, the monotonic axial behavior differs from the envelope of cyclic behavior. The plastic strains of the actively confined concrete show a similar trend to those of passive confinement. This study proposed plastic strain models for concrete confined by SMA wire or steel jackets. For the volumetric strain, the active jackets of NiTiNb SMA wires provide more energy dissipation than the passive jacket of steel.
4. 21 CFR 175.320 - Resinous and polymeric coatings for polyolefin films. Code of Federal Regulations, 2012 CFR 2012-04-01 ... coating is applied as a continuous film over one or both sides of a base film produced from one or more of the basic olefin polymers complying with § 177.1520 of this chapter. The base polyolefin film may... as are provided: List of substances Limitations [i] Resins and polymers: Acrylic acid polymer and its...
5. 21 CFR 175.320 - Resinous and polymeric coatings for polyolefin films. Code of Federal Regulations, 2013 CFR 2013-04-01 ... coating is applied as a continuous film over one or both sides of a base film produced from one or more of the basic olefin polymers complying with § 177.1520 of this chapter. The base polyolefin film may... as are provided: List of substances Limitations [i] Resins and polymers: Acrylic acid polymer and its...
6. Studies of Luminescence Performance on Carbazole Donor and Quinoline Acceptor Based Conjugated Polymer. PubMed Upadhyay, Anjali; S, Karpagam 2016-03-01 We report on the synthesis of conjugated polymer [CV-QP] containing carbazole [donor] and quinoline [acceptor] using Wittig methodology. The structural, optical and thermal properties of the polymer were investigated by FT-IR, NMR, GPC, UV, PL, cyclic voltammetry, atomic force microscopy [AFM] and thermogravimetric analysis [TGA]. The polymer exhibits thermal stability upto 200 °C and shows good solubility in common organic solvents. The polymer has optical absorption band in a thin film at 360 nm and emission band formed at 473 nm. The optical energy band gap was found to be 2.69 eV as calculated from the onset absorption edge. Fluorescence quenching of the polymer CV-QP was found by using DMA [electron donor] and DMTP [electron acceptor]. AFM image indicated that triangular shaped particles were observed and the particle size was found as 1.1 μm. The electrochemical studies of CV-QP reveal that, the highest occupied molecular orbital [HOMO] and lowest unoccupied molecular orbital [LUMO] energy levels of the CV-QP are 6.35 and 3.70 eV, which indicated that the polymers are expected to provide charge transporting properties for the development of polymer light-emitting diodes [PLEDs].
7. Tunable thiol-epoxy shape memory polymer foams NASA Astrophysics Data System [ADS] Ellson, Gregory; Di Prima, Matthew; Ware, Taylor; Tang, Xiling; Voit, Walter 2015-05-01 Shape memory polymers [SMPs] are uniquely suited to a number of applications due to their shape storage and recovery abilities and the wide range of available chemistries. However, many of the desired performance properties are tied to the polymer chemistry which can make optimization difficult. The use of foaming techniques is one way to tune mechanical response of an SMP without changing the polymer chemistry. In this work, a novel thiol-epoxy SMP was foamed using glass microspheres [40 and 50% by volume Q-Cel 6019], using expandable polymer microspheres [1% 930 DU 120], and by a chemical blowing agent [1% XOP-341]. Each approach created SMP foam with a differing density and microstructure from the others. Thermal and thermomechanical analysis was performed to observe the behavioral difference between the foaming techniques and to confirm that the glass transition [Tg] was relatively unchanged near 50 °C while the glassy modulus varied from 19.1 to 345 MPa and the rubbery modulus varied from 0.04 to 2.2 MPa. The compressive behavior of the foams was characterized through static compression testing at different temperatures, and cyclic compression testing at Tg. Constrained shape recovery testing showed a range of peak recovery stress from 5 MPa for the syntactic Q-Cel foams to ˜0.1 MPa for the chemically blown XOP-341 foam. These results showed that multiple foaming approaches can be used with a novel SMP to vary the mechanical response independent of Tg and polymer chemistry.
8. Conducting polymers with immobilised fibrillar collagen for enhanced neural interfacing. PubMed Liu, Xiao; Yue, Zhilian; Higgins, Michael J; Wallace, Gordon G 2011-10-01 Conducting polymers with pendant functionality are advantageous in various bionic and organic bioelectronic applications, as they allow facile incorporation of bio-regulative cues to provide bio-mimicry and conductive environments for cell growth, differentiation and function. In this work, polypyrrole substrates doped with chondroitin sulfate [CS], an extracellular matrix molecule bearing carboxylic acid moieties, were electrochemically synthesized and conjugated with type I collagen. During the coupling process, the conjugated collagen formed a 3-dimensional fibrillar matrix in situ at the conducting polymer interface, as evidenced by atomic force microscopy [AFM] and fluorescence microscopy under aqueous physiological conditions. Cyclic voltammetry [CV] and impedance measurement confirmed no significant reduction in the electroactivity of the fibrillar collagen-modified conducting polymer substrates. Rat pheochromocytoma [nerve] cells showed increased differentiation and neurite outgrowth on the fibrillar collagen, which was further enhanced through electrical stimulation of the underlying conducting polymer substrate. Our study demonstrates that the direct coupling of ECM components such as collagen, followed by their further self-assembly into 3-dimensional matrices, has the potential to improve the neural-electrode interface of implant electrodes by encouraging nerve cell attachment and differentiation. Copyright © 2011 Elsevier Ltd. All rights reserved.
9. Sequencing Cyclic Peptides by Multistage Mass Spectrometry PubMed Central Mohimani, Hosein; Yang, Yu-Liang; Liu, Wei-Ting; Hsieh, Pei-Wen; Dorrestein, Pieter C.; Pevzner, Pavel A. 2012-01-01 Some of the most effective antibiotics [e.g., Vancomycin and Daptomycin] are cyclic peptides produced by non-ribosomal biosynthetic pathways. While hundreds of biomedically important cyclic peptides have been sequenced, the computational techniques for sequencing cyclic peptides are still in their infancy. Previous methods for sequencing peptide antibiotics and other cyclic peptides are based on Nuclear Magnetic Resonance spectroscopy, and require large amount [miligrams] of purified materials that, for most compounds, are not possible to obtain. Recently, development of mass spectrometry based methods has provided some hope for accurate sequencing of cyclic peptides using picograms of materials. In this paper we develop a method for sequencing of cyclic peptides by multistage mass spectrometry, and show its advantages over single stage mass spectrometry. The method is tested on known and new cyclic peptides from Bacillus brevis, Dianthus superbus and Streptomyces griseus, as well as a new family of cyclic peptides produced by marine bacteria. PMID:21751357
10. Triboelectric energy harvesting with surface-charge-fixed polymer based on ionic liquid PubMed Central Sano, Chikako; Mitsuya, Hiroyuki; Ono, Shimpei; Miwa, Kazumoto; Toshiyoshi, Hiroshi; Fujita, Hiroyuki 2018-01-01 Abstract A novel triboelectric energy harvester has been developed using an ionic liquid polymer with cations fixed at the surface. In this report, the fabrication of the device and the characterization of its energy harvesting performance are detailed. An electrical double layer was induced in the ionic liquid polymer precursor to attract the cations to the surface where they are immobilized using a UV-based crosslinking reaction. The finalized polymer is capable of generating an electrical current when contacted by a metal electrode. Using this property, energy harvesting experiments were conducted by cyclically contacting a gold-surface electrode with the charge fixed surface of the polymer. Control experiments verified the effect of immobilizing the cations at the surface. By synthesizing a polymer with the optimal composition ratio of ionic liquid to macromonomer, an output of 77 nW/cm2 was obtained with a load resistance of 1 MΩ at 1 Hz. This tuneable power supply with a μA level current output may contribute to Internet of Things networks requiring numerous sensor nodes at remote places in the environment. PMID:29707070
11. Redox-active porous coordination polymer based on trinuclear pivalate: Temperature-dependent crystal rearrangement and redox-behavior DOE Office of Scientific and Technical Information [OSTI.GOV] Lytvynenko, Anton S.; Kiskin, Mikhail A., E-mail: mkiskin@igic.ras.ru; Dorofeeva, Victoria N. 2015-03-15 Linking of trinuclear pivalate Fe{sub 2}NiO[Piv]{sub 6} [Piv=O{sub 2}CC[CH{sub 3}]{sub 3}] by 2,6-bis[4-pyridyl]-4-[1-naphthyl]pyridine [L] resulted in formation of 1D-porous coordination polymer Fe{sub 2}NiO[Piv]{sub 6}[L]·Solv, which was characterized in two forms: DMSO solvate Fe{sub 2}NiO[Piv]{sub 6}[L][DMSO]·2.5DMSO [1] or water solvate Fe{sub 2}NiO[Piv]{sub 6}[L][H{sub 2}O] [2]. X-ray structure of 1 was determined. Crystal lattice of 1 at 160 K contained open channels, filled by captured solvent, while temperature growth to 296 K led to the crystal lattice rearrangement and formation of closed voids. Redox-behavior of 2 was studied by cyclic voltammetry for a solid compound, deposited on glassy-carbon electrode. Redox-activity of Lmore » preserved upon incorporation in the coordination polymer. The presence of pores in desolvated sample Fe{sub 2}NiO[Piv]{sub 6}[L] was confirmed by the measurements of N{sub 2} and H{sub 2} adsorption at 77 K. Potential barriers of the different molecules diffusion through pores were estimated by the means of molecular mechanics. - Graphical abstract: Redox-behavior of 1D-porous coordination polymer Fe{sub 2}NiO[Piv]{sub 6}[L][H{sub 2}O] was studied by cyclic voltammetry in thin film, deposited on glassy-carbon electrode. Redox-activity of L preserved upon incorporation in the coordination polymer. Potential barriers of different molecules diffusion through pores were estimated by the means of molecular mechanics. - Highlights: • Porous 1D coordination polymer was synthesized. • Temperature growth led to pores closing due to crystal lattice rearrangement. • Redox-activity of ligand preserved upon incorporation into coordination polymer. • Redox-properties of solid coordination polymer were studied in thin film. • Diffusion barriers were evaluated by molecular mechanics.« less
12. Novel Conjugated Polymers Prepared by Direct [Hetero] arylation: An Eco-Friendly Tool for Organic Electronics. PubMed Liu, Fuchuan; Zhang, Yangqian; Wang, Hang; Zhang, Shiming 2018-02-13 The phthalimide [PhI] moiety has been attracting more attention as an excellent acceptor building block in donor-acceptor [D-A] conjugated polymers. In this paper; three D-A conjugated polymers with or without thiocarbonyl moieties are successfully prepared by the direct [hetero]-arylation polymerization [DHAP], which is an atom efficient and facile synthetic strategy to obtain polymer materials. Compared with the traditional carbon-carbon coupling reactions, this method possesses more advantages, including: fewer synthetic steps, avoidance of the preparation of the organometallic reagents, higher atom economy and fewer toxic byproducts, better compatibility with chemically sensitive functional groups and so on. All three of these designed PhI-based polymers exhibited favourable optoelectronic and thermal performance. The optical, thermodynamic and electrochemical properties of the synthesized polymers were systematically investigated using ultraviolet-visible [UV-vis] spectroscopy, thermogravimetric analysis [TGA], differential scanning calorimetry [DSC] and cyclic voltammetry [CV]. The results of these three polymers indicated that thionation of the carbonyl was a highly effective methods to improve the properties of PhI-based polymers; and provided impetus for the development of thionated PhI derivatives for organic electronic applications.
13. Novel [meth]acrylate monomers for ultrarapid polymerization and enhanced polymer properties DOE Office of Scientific and Technical Information [OSTI.GOV] Beckel, E. R.; Berchtold, K. A.; Nie, J. 2002-01-01 Ultraviolet light is known to be one of the most efficient methods to initiatc polymeric reactions in the presence of a photonitiator. Photopolymerizations are advantageous because the chemistry of the materials can be tailored to design liquid monomers for ultrarapid polymerization into a solid polymer material. One way to achieve rapid photopolymerizations is to utilize multifunctional [meth]acrylate monomers. which form highly crosslinked polymers; however, these monomers typically do not achieve complete functional group conversion. Recently, Decker et al. developed novel monovinyl acrylate monomers that display polyriicrization kinetics that rival those of multifunctional acrylate monomers. These novel acrylate monomers incorporate secondarymore » functionalities and end groups such as carbonates, carbamates, cyclic carbonates and oxazolidone which promote the increased polymerization kinetics of these monomers. In addition to thc polynierization kinetics, these novel monovinyl monomers form crosslinked polymers, which are characterized by having high strength and high flexibility. Unfortunately, the exact mechanism or mechanisms responsible for the polymerization kinetics and crosslinking are not well understood.« less
14. A review study of [bio]sensor systems based on conducting polymers. PubMed Ates, Murat 2013-05-01 This review article concentrates on the electrochemical biosensor systems with conducting polymers. The area of electro-active polymers confined to different electrode surfaces has attracted great attention. Polymer modified carbon substrate electrodes can be designed through polymer screening to provide tremendous improvements in sensitivity, selectivity, stability and reproducibility of the electrode response to detect a variety of analytes. The electro-active films have been used to entrap different enzymes and/or proteins at the electrode surface, but without obvious loss of their bioactivity for the development of biosensors. Electropolymerization is a well-known technique used to immobilize biomaterials to the modified electrode surface. Polymers might be covalently bonding to enzymes or proteins; therefore, thickness, permeation and charge transport characteristics of the polymeric films can be easily and precisely controlled by modulating the electrochemical parameters for various electrochemical techniques, such as chronoamperometry, chronopotentiometry, cyclic voltammetry, and differential pulse voltammetry. This review article is divided into three main parts as given in the table of contents related to the immobilization process of some important conducting polymers, polypyrrole, polythiophene, poly[3,4-ethylenedioxythiophene], polycarbazole, polyaniline, polyphenol, poly[o-phenylenediamine], polyacetylene, polyfuran and their derivatives. A total of 216 references are cited in this review article. The literature reviewed covers a 7 year period beginning from 2005. Copyright © 2013 Elsevier B.V. All rights reserved.
15. Highly enantioselective alpha-aminoxylation of aldehydes and ketones with a polymer-supported organocatalyst. PubMed Font, Daniel; Bastero, Amaia; Sayalero, Sonia; Jimeno, Ciril; Pericàs, Miquel A 2007-05-10 The first catalytic enantioselective alpha-aminoxylation of aldehydes and ketones using an insoluble, polymer-supported organocatalyst [1] derived from trans-4-hydroxyproline is reported [ee: 96-99%]. Reaction rates in the aminoxylation of cyclic ketones with 1 are higher than those reported with l-proline. The insoluble nature of 1 simplifies workup conditions and allows catalyst recycling without an apparent decrease in enantioselectivity or yield.
16. Targeted delivery of 10-hydroxycamptothecin to human breast cancers by cyclic RGD-modified lipid-polymer hybrid nanoparticles. PubMed Yang, Zhe; Luo, Xingen; Zhang, Xiaofang; Liu, Jie; Jiang, Qing 2013-04-01 Lipid-polymer hybrid nanoparticles [NPs] combining the positive attributes of both liposomes and polymeric NPs are increasingly being considered as promising candidates to carry therapeutic agents safely and efficiently into targeted sites. Herein, a modified emulsification technique was developed and optimized for the targeting lipid-polymer hybrid NPs fabrication; the surface properties and stability of the hybrid NPs were systematically investigated, which confirmed that the hybrid NPs consisted of a poly [lactide-co-glycolide] core with ∼90% surface coverage of the lipid monolayer and a ∼4.4 nm hydrated polyethylene glycol [PEG] shell. Optimization results showed that the lipid:polymer mass ratio and the lipid-PEG:lipid molar ratio could affect the size, lipid association efficiency and stability of hybrid NPs. Furthermore, a model chemotherapy drug, 10-hydroxycamptothecin, was encapsulated into hybrid NPs with a higher drug loading compared to PLGA NPs. Surface modification of the lipid layer and the PEG conjugated targeting ligand did not affect their drug release kinetics. Finally, the cytotoxicity and cellular uptake studies indicated that the lipid coverage and the c[RGDyk] conjugation of the hybrid NPs gained a significantly enhanced ability of cell killing and endocytosis. Our results suggested that lipid-polymer hybrid NPs prepared by the modified emulsion technique have great potential to be utilized as an engineered drug delivery system with precise control ability of surface targeting modification.
17. Sequential shrink photolithography for plastic microlens arrays NASA Astrophysics Data System [ADS] Dyer, David; Shreim, Samir; Jayadev, Shreshta; Lew, Valerie; Botvinick, Elliot; Khine, Michelle 2011-07-01 Endeavoring to push the boundaries of microfabrication with shrinkable polymers, we have developed a sequential shrink photolithography process. We demonstrate the utility of this approach by rapidly fabricating plastic microlens arrays. First, we create a mask out of the children's toy Shrinky Dinks by simply printing dots using a standard desktop printer. Upon retraction of this pre-stressed thermoplastic sheet, the dots shrink to a fraction of their original size, which we then lithographically transfer onto photoresist-coated commodity shrink wrap film. This shrink film reduces in area by 95% when briefly heated, creating smooth convex photoresist bumps down to 30 µm. Taken together, this sequential shrink process provides a complete process to create microlenses, with an almost 99% reduction in area from the original pattern size. Finally, with a lithography molding step, we emboss these bumps into optical grade plastics such as cyclic olefin copolymer for functional microlens arrays.
18. Sequential shrink photolithography for plastic microlens arrays. PubMed Dyer, David; Shreim, Samir; Jayadev, Shreshta; Lew, Valerie; Botvinick, Elliot; Khine, Michelle 2011-07-18 Endeavoring to push the boundaries of microfabrication with shrinkable polymers, we have developed a sequential shrink photolithography process. We demonstrate the utility of this approach by rapidly fabricating plastic microlens arrays. First, we create a mask out of the children's toy Shrinky Dinks by simply printing dots using a standard desktop printer. Upon retraction of this pre-stressed thermoplastic sheet, the dots shrink to a fraction of their original size, which we then lithographically transfer onto photoresist-coated commodity shrink wrap film. This shrink film reduces in area by 95% when briefly heated, creating smooth convex photoresist bumps down to 30 µm. Taken together, this sequential shrink process provides a complete process to create microlenses, with an almost 99% reduction in area from the original pattern size. Finally, with a lithography molding step, we emboss these bumps into optical grade plastics such as cyclic olefin copolymer for functional microlens arrays.
19. Multiwavelength laser light transmission of hollow optical fiber from the visible to the mid-infrared. PubMed Shi, Yi Wei; Ito, Kentaro; Matsuura, Yuji; Miyagi, Mitsunobu 2005-11-01 We report on low-loss multiwavelength laser delivery of hollow optical fiber in a wide wavelength region, from the visible to the infrared. Improved methods of liquid-phase coating were used to fabricate the hollow fiber with inner films of a silver and a cyclic olefin polymer [COP] layer. The surface roughness of the silver layer was reduced dramatically by pretreatment on the inner glass surface with an SnCl2 solution. The COP layer roughness was also decreased by using an ambient atmosphere of tetrahydrofuran [THF] solvent during the COP layer formation. Owing to the smooth surfaces, hollow fiber with optimum COP film thickness for CO2 laser light simultaneously yields low losses for a Er:YAG laser and a red pilot beam. The power durability of CO2 and Er:YAG lasers, as well as the loss properties for the pilot beam, is demonstrated.
20. Advanced Proton Conducting Polymer Electrolytes for Electrochemical Capacitors NASA Astrophysics Data System [ADS] Gao, Han . The optimized polymer electrolyte demonstrated even higher proton conductivity than pure HPAs and the enabled electrochemical capacitors have demonstrated an exceptionally high rate capability of 50 Vs-1 in cyclic voltammograms and a 10 ms time constant in impedance analyses.

1. Are Math Grades Cyclical? ERIC Educational Resources Information Center Adams, Gerald J.; Dial, Micah 1998-01-01 The cyclical nature of mathematics grades was studied for a cohort of elementary school students from a large metropolitan school district in Texas over six years [average cohort size of 8495]. The study used an autoregressive integrated moving average [ARIMA] model. Results indicate that grades do exhibit a significant cyclical pattern. [SLD]
2. 40 CFR Appendix 8 to Subpart A of... - Reference C16-C18 Internal Olefin Drilling Fluid Formulation Code of Federal Regulations, 2010 CFR 2010-07-01 ... 40 Protection of Environment 29 2010-07-01 2010-07-01 false Reference C16-C18 Internal Olefin Drilling Fluid Formulation 8 Appendix 8 to Subpart A of Part 435 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY [CONTINUED] EFFLUENT GUIDELINES AND STANDARDS OIL AND GAS EXTRACTION POINT SOURCE CATEGORY...
3. 40 CFR Appendix 8 to Subpart A of... - Reference C16-C18 Internal Olefin Drilling Fluid Formulation Code of Federal Regulations, 2011 CFR 2011-07-01 ... 40 Protection of Environment 30 2011-07-01 2011-07-01 false Reference C16-C18 Internal Olefin Drilling Fluid Formulation 8 Appendix 8 to Subpart A of Part 435 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY [CONTINUED] EFFLUENT GUIDELINES AND STANDARDS OIL AND GAS EXTRACTION POINT SOURCE CATEGORY...
4. Effect of cyclic fatigue on the fracture toughness of Polyoxymethylene NASA Astrophysics Data System [ADS] Ramoa, B.; Berer, M.; Schwaiger, M.; Pinter, G. 2017-05-01 Polymers are used in a wide range of applications and their properties are dependent upon the morphological development during processing and the specimen configuration which in turn define the mechanical properties. In this context fatigue and monotonic testing are part of the standard procedure to assess relevant mechanical and material parameters to ensure a better part design. The present work addresses the performance issues of a real component made of Polyoxymethylene [POM] which is subjected to cyclic loads from intermediate levels to high peak values inside a damping mechanism. For this linear elastic fracture mechanics concepts were used to characterize the behavior of a POM homopolymer resin used in this application. Injection molded compact tension specimens, with sharp and blunt notches, were tested under a combination of cyclic and monotonic loads and the fracture surfaces were examined. The critical stress intensity factor obtained by monotonic tests was evaluated as a function of the cycle number, where an increase after the first 1000 cycles followed by a continuous decrease with higher numbers of cycles was observed. A variation of approximately 50% and 70% were obtained along the duration of the tests for the sharp and blunt notch specimens, respectively. In light of the obtained results, a discussion is presented considering the dynamic specimen compliance and the structural features observed on the fracture surfaces in combination with the fracture mechanical response.
5. 40 CFR 721.2120 - Cyclic amide. Code of Federal Regulations, 2010 CFR 2010-07-01 ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Cyclic amide. 721.2120 Section 721... Cyclic amide. [a] Chemical substance and significant new uses subject to reporting. [1] The chemical substance identified as a cyclic amide [PMN P-92-131] is subject to reporting under this section for the...
6. Methanol conversion to light olefins over nanostructured CeAPSO-34 catalyst: Thermodynamic analysis of overall reactions and effect of template type on catalytic properties and performance DOE Office of Scientific and Technical Information [OSTI.GOV] Aghamohammadi, Sogand; Reactor and Catalysis Research Center; Haghighi, Mohammad, E-mail: haghighi@sut.ac.ir 2014-02-01 Graphical abstract: In this research nanostructured CeAPSO-34 was synthesized to explore the effect of TEAOH and morpholine on its physiochemical properties and MTO performance. Prepared catalysts were characterized with XRD, FESEM, BET, FTIR and NH3-TPD techniques. The results indicated that the nature of the template determines the physiochemical properties of CeAPSO-34 due to different rate of crystal growth. The catalyst obtained by using morpholine showed longer life time as well as sustaining light olefins selectivity at higher values. Furthermore, a comprehensive thermodynamic analysis of overall reactions network was carried out to address the major channels of methanol to olefins conversion.more » - Highlights: • Introduction of Ce into SAPO-34 framework. • Comparison of CeAPSO-34 synthesized using morpholine and TEAOH. • The nature of the template determines the physiochemical properties of CeAPSO-34. • Morpholine enhances catalyst lifetime in MTO process. • Presenting a complete reaction network for MTO process. - Abstract: TEAOH and morpholine were employed in synthesis of nanostructured CeAPSO-34 molecular sieve and used in methanol to olefins conversion. Prepared samples were characterized by XRD, FESEM, EDX, BET, FTIR and NH{sub 3}-TPD techniques. XRD patterns reflected the higher crystallinity of the catalyst synthesized with morpholine. The FESEM results indicated that the nature of the template determines the morphology of nanostructured CeAPSO-34 due to different rate of crystal growth. There was a meaningful difference in the strength of both strong and weak acid sites for CeAPSO-34 catalysts synthesized with TEAOH and morpholine templates. The catalyst synthesized with morpholine showed higher desorption temperature of both weak and strong acid sites evidenced by NH{sub 3}-TPD characterization. The catalyst obtained using morpholine template had the longer lifetime and sustained desired light olefins at higher values. A
7. Cyclic completion of the anamorphic universe NASA Astrophysics Data System [ADS] Ijjas, Anna 2018-04-01 Cyclic models of the universe have the advantage of avoiding initial conditions problems related to postulating any sort of beginning in time. To date, the best known viable examples of cyclic models have been ekpyrotic. In this paper, we show that the recently proposed anamorphic scenario can also be made cyclic. The key to the cyclic completion is a classically stable, non-singular bounce. Remarkably, even though the bounce construction was originally developed to connect a period of contraction with a period of expansion both described by Einstein gravity, we show here that it can naturally be modified to connect an ordinary contracting phase described by Einstein gravity with a phase of anamorphic smoothing. The paper will present the basic principles and steps in constructing cyclic anamorphic models.
8. Full Scale RC Beam-Column Joints Strengthened with Steel Reinforced Polymer Systems NASA Astrophysics Data System [ADS] De Vita, Alessandro; Napoli, Annalisa; Realfonzo, Roberto 2017-07-01 This paper presents the results of an experimental campaign performed at the Laboratory of Materials and Structural Testing of the University of Salerno [Italy] in order to investigate the seismic performance of RC beam-column joints strengthened with Steel Reinforced Polymer [SRP] systems. With the aim to represent typical façade frames’ beam-column subassemblies found in existing RC buildings, specimens were provided with two short beam stubs orthogonal to the main beam and were designed with inadequate seismic details. Five members were strengthened by using two different SRP layouts while the remaining ones were used as benchmarks. Once damaged, two specimens were also repaired, retrofitted with SRP and subjected to cyclic test again. The results of cyclic tests performed on SRP strengthened joints are examined through a comparison with the outcomes of the previous experimental program including companion specimens not provided with transverse beam stubs and strengthened by Carbon Fiber Reinforced Polymer [CFRP] systems. In particular, both qualitative and quantitative considerations about the influence of the confining effect provided by the secondary beams on the joint response, the suitability of all the adopted strengthening solutions [SRP/CFRP systems], the performances and the failure modes experienced in the several cases studied are provided.
9. News from Online: Industrial Chemicals and Polymers NASA Astrophysics Data System [ADS] Sweeney Judd, Carolyn 1999-02-01 of the American Chemical Society Divisions of Polymer Chemistry and Polymeric Materials: Science and Engineering and General Electric Corporation. The POLYED site, / /chemdept.uwsp.edu/polyed/index.htm, is hosted by the University of Wisconsin at Stevens Point. This National Center for Polymer Education is another good place to go for information. More education is available at the Ziegler Research Group Home Page at //www.chem.ucalgary.ca/groups/ziegler/index.html . Go to Metallocene as Olefin Polymerization Catalysis: An Introduction [ //www.chem.ucalgary.ca/groups/ziegler/met_intro.html ] for historical accounts of metallocene and Ziegler-Natta catalysts. Movies are available here too. This Canadian site is well-documented and educational. Back at the University of Wisconsin-Madison, The Why Files site at //whyfiles.news.wisc.edu helps bring important chemical and technology news to the public. Go to the archived files of October 1997 [ //whyfiles.news.wisc.edu/shorties/catalyst.html ] to find information about the importance of low-temperature metallocene catalysts. The Why Files received funding from the National Science Foundation. Go here for science information in an easy-to-read format. One of the driving forces toward better catalysis is the attempt to reach 100% product, combining efficiency with lowered pollution. Companies can look to the Environmental Protection Agency for information: Environsense at //es.epa.gov/ is pledged to offer "Common Sense Solutions to Environmental Problems". So where can we get these polymers? The American Chemical Society can help. Go to Chemcylopedia at //pubs.acs.org/chemcy99/ for great information. Both purchasers and users of chemicals can benefit from this site. Searches can be made on the chemical or on the supplier. Information provided includes CAS Registry Numbers and special shipping requirements as well as potential applications. Do you remember that we started with paper? Let
10. Dialkylthio Substitution: An Effective Method to Modulate the Molecular Energy Levels of 2D-BDT Photovoltaic Polymers. PubMed Yao, Huifeng; Zhang, Hao; Ye, Long; Zhao, Wenchao; Zhang, Shaoqing; Hou, Jianhui 2016-02-17 Dialkylthio-substituted thienyl-benzodithiophene [BDT-DST] was designed and synthesized as a building block to modulate the molecular levels of the conjugated polymers, and three copolymers named PDST-BDD, PDST-TT and PDST-DPP were prepared and applied in polymer solar cells [PSCs]. Theoretical calculations and electrochemical cyclic voltammetry [CV] measurement suggested that the dialkylthio group could decrease the molecular energy levels of the resulting polymers distinctly. The open-circuit voltage [VOC] of PSC devices based on PDST-BDD, PDST-TT, and PDST-DPP are as high as 1.0, 0.98, and 0.88 V, respectively, which are ∼0.15 V higher than those of the corresponding alky-substituted analogues. Moreover, the influence of the dialkylthio group on the absorption spectra, crystalline properties, hole mobilities, and blend morphologies of the polymers was also investigated. The results indicate that the dialkythio substitution is an effective method to modulate the molecular energy levels and that the BDT-DST unit has potential for constructing high-efficiency photovoltaic polymers.
11. History-independent cyclic response of nanotwinned metals NASA Astrophysics Data System [ADS] Pan, Qingsong; Zhou, Haofei; Lu, Qiuhong; Gao, Huajian; Lu, Lei 2017-11-01 Nearly 90 per cent of service failures of metallic components and structures are caused by fatigue at cyclic stress amplitudes much lower than the tensile strength of the materials involved. Metals typically suffer from large amounts of cumulative, irreversible damage to microstructure during cyclic deformation, leading to cyclic responses that are unstable [hardening or softening] and history-dependent. Existing rules for fatigue life prediction, such as the linear cumulative damage rule, cannot account for the effect of loading history, and engineering components are often loaded by complex cyclic stresses with variable amplitudes, mean values and frequencies, such as aircraft wings in turbulent air. It is therefore usually extremely challenging to predict cyclic behaviour and fatigue life under a realistic load spectrum. Here, through both atomistic simulations and variable-strain-amplitude cyclic loading experiments at stress amplitudes lower than the tensile strength of the metal, we report a history-independent and stable cyclic response in bulk copper samples that contain highly oriented nanoscale twins. We demonstrate that this unusual cyclic behaviour is governed by a type of correlated ‘necklace’ dislocation consisting of multiple short component dislocations in adjacent twins, connected like the links of a necklace. Such dislocations are formed in the highly oriented nanotwinned structure under cyclic loading and help to maintain the stability of twin boundaries and the reversible damage, provided that the nanotwins are tilted within about 15 degrees of the loading axis. This cyclic deformation mechanism is distinct from the conventional strain localizing mechanisms associated with irreversible microstructural damage in single-crystal, coarse-grained, ultrafine-grained and nanograined metals.
12. Two-dimensional interferometric characterization of laser-induced refractive index profiles in bulk Topas polymer NASA Astrophysics Data System [ADS] Hessler, Steffen; Rosenberger, Manuel; Schmauss, Bernhard; Hellmann, Ralf 2018-01-01 In this paper we precisely determine laser-induced refractive index profiles created in cyclic olefin copolymer Topas 6017 employing a sophisticated phase shifting Mach-Zehnder interferometry approach. Beyond the usual one-dimensional modification depth measurement we highlight that for straight waveguide structures also a two-dimensional refractive index distribution can be directly obtained providing full information of a waveguide's exact cross section and its gradient refractive index contrast. Deployed as direct data input in optical waveguide simulation, the evaluated 2D refractive index profiles permit a detailed calculation of the waveguides' actual mode profiles. Furthermore, conventional one-dimensional interferometric measurements for refractive index depth profiles with varying total imposed laser fluence of a 248 nm KrF excimer laser are included to investigate the effect on refractive index modification depth. Maximum surface refractive index increase turns out to attain up to 1.86 ·10-3 enabling laser-written optical waveguide channels. Additionally, a comprehensive optical material characterization in terms of dispersion, thermo-optic coefficient and absorption measurement of unmodified and UV-modified Topas 6017 is carried out.
13. A cup product structure for cyclic cohomology NASA Astrophysics Data System [ADS] Espinosa Tintos, Jose Eduardo In this work we construct a cup product structure for cyclic cohomology of a cyclic set X. introduced by Comics. We make use of a categorical construction of cyclic homology by Fiedorowicz and Loday to define our cup product structure by using a large resolution of the cyclic category. We also provide a way to construct a chain map from a smaller resolution where the action of the finite groups is clear. and in the process of constructing this map we learn the large complex can be viewed as all factorizations in the category DeltaC using the cyclic structure of X.
14. Nanoparticle amount, and not size, determines chain alignment and nonlinear hardening in polymer nanocomposites PubMed Central Varol, H. Samet; Meng, Fanlong; Hosseinkhani, Babak; Malm, Christian; Bonn, Daniel; Bonn, Mischa; Zaccone, Alessio 2017-01-01 Polymer nanocomposites—materials in which a polymer matrix is blended with nanoparticles [or fillers]—strengthen under sufficiently large strains. Such strain hardening is critical to their function, especially for materials that bear large cyclic loads such as car tires or bearing sealants. Although the reinforcement [i.e., the increase in the linear elasticity] by the addition of filler particles is phenomenologically understood, considerably less is known about strain hardening [the nonlinear elasticity]. Here, we elucidate the molecular origin of strain hardening using uniaxial tensile loading, microspectroscopy of polymer chain alignment, and theory. The strain-hardening behavior and chain alignment are found to depend on the volume fraction, but not on the size of nanofillers. This contrasts with reinforcement, which depends on both volume fraction and size of nanofillers, potentially allowing linear and nonlinear elasticity of nanocomposites to be tuned independently. PMID:28377517
15. Novel aminobenzyl and imidobenzyl benzenes NASA Technical Reports Server [NTRS] Bell, V. L.; Pratt, J. R.; Stump, B. L. 1976-01-01 Compounds are useful as intermediates for several classes of polymers. Amines can function as cross-linking agents for epoxide and urethane polymers, as well as intermediates for synthesis of thermally-stable addition-type polyimides. Imide derivatives can be obtained by reacting amines with certain monoanhydrides containing olefinic unsaturation.
16. Analysis of linear and cyclic oligomers in polyamide-6 without sample preparation by liquid chromatography using the sandwich injection method. II. Methods of detection and quantification and overall long-term performance. PubMed Mengerink, Y; Peters, R; Kerkhoff, M; Hellenbrand, J; Omloo, H; Andrien, J; Vestjens, M; van der Wal, S 2000-05-05 By separating the first six linear and cyclic oligomers of polyamide-6 on a reversed-phase high-performance liquid chromatographic system after sandwich injection, quantitative determination of these oligomers becomes feasible. Low-wavelength UV detection of the different oligomers and selective post-column reaction detection of the linear oligomers with o-phthalic dicarboxaldehyde [OPA] and 3-mercaptopropionic acid [3-MPA] are discussed. A general methodology for quantification of oligomers in polymers was developed. It is demonstrated that the empirically determined group-equivalent absorption coefficients and quench factors are a convenient way of quantifying linear and cyclic oligomers of nylon-6. The overall long-term performance of the method was studied by monitoring a reference sample and the calibration factors of the linear and cyclic oligomers.
17. Improving Olefin Purification Using Metal Organic Frameworks with Open Metal Sites. PubMed Luna-Triguero, A; Vicent-Luna, J M; Poursaeidesfahani, A; Vlugt, T J H; Sánchez-de-Armas, R; Gómez-Álvarez, P; Calero, S 2018-05-16 The separation and purification of light hydrocarbons is challenging in the industry. Recently, a ZJNU-30 metal-organic framework [MOF] has been found to have the potential for adsorption-based separation of olefins and diolefins with four carbon atoms [H. M. Liu et al. Chem.-Eur. J. 2016, 22, 14988-14997]. Our study corroborates this finding but reveals Fe-MOF-74 as a more efficient candidate for the separation because of the open metal sites. We performed adsorption-based separation, transient breakthrough curves, and density functional theory calculations. This combination of techniques provides an extensive understanding of the studied system. Using this MOF, we propose a separation scheme to obtain a high-purity product.
18. Catalytic asymmetric dihydroxylation of olefins using a recoverable and reusable OsO[4]2- in ionic liquid [bmim][PF6]. PubMed Branco, Luís C; Afonso, Carlos A M 2002-12-21 The use of the solvent systems water/ionic liquid or water/ionic liquid/tert-butanol provides a recoverable, reusable, robust and simple system for the asymmetric dihydroxylation of olefins, based on the immobilization of the osmium-ligand catalyst in the ionic liquid phase.
19. Toward structure prediction of cyclic peptides. PubMed Yu, Hongtao; Lin, Yu-Shan 2015-02-14 Cyclic peptides are a promising class of molecules that can be used to target specific protein-protein interactions. A computational method to accurately predict their structures would substantially advance the development of cyclic peptides as modulators of protein-protein interactions. Here, we develop a computational method that integrates bias-exchange metadynamics simulations, a Boltzmann reweighting scheme, dihedral principal component analysis and a modified density peak-based cluster analysis to provide a converged structural description for cyclic peptides. Using this method, we evaluate the performance of a number of popular protein force fields on a model cyclic peptide. All the tested force fields seem to over-stabilize the α-helix and PPII/β regions in the Ramachandran plot, commonly populated by linear peptides and proteins. Our findings suggest that re-parameterization of a force field that well describes the full Ramachandran plot is necessary to accurately model cyclic peptides.
20. Modeling of high-strength concrete-filled FRP tube columns under cyclic load NASA Astrophysics Data System [ADS] Ong, Kee-Yen; Ma, Chau-Khun; Apandi, Nazirah Mohd; Awang, Abdullah Zawawi; Omar, Wahid 2018-05-01 The behavior of high-strength concrete [HSC] - filled fiber-reinforced-polymer [FRP] tubes [HSCFFTs] column subjected to cyclic lateral loading is presented in this paper. As the experimental study is costly and time consuming, a finite element analysis [FEA] is chosen for the study. Most of the previous studies have focused on examining the axial load behavior of HSCFFT column instead of seismic behavior. The seismic behavior of HSCFFT columns has been the main interest in the industry. The key objective of this research is to develop a reliable numerical non-linear FEA model to represent the seismic behavior of such column. A FEA model was developed using the Concrete Damaged Plasticity Model [CDPM] available in the finite element software package [ABAQUS]. Comparisons between experimental results from previous research and the predicted results were made based on load versus displacement relationships and ultimate strength of the column. The results showed that the column increased in ductility and able to deform to a greater extent with the increase of the FRP confinement ratio. With the increase of confinement ratio, HSCFFT column achieved a higher moment resistance, thus indicated a higher failure strength in the column under cyclic lateral load. It was found that the proposed FEA model can regenerate the experimental results with adequate accuracy.

1. Elucidation of the Cross-Link Structure of Nadic-End-Capped Polyimides Using NMR of C-13-Labeled Polymers NASA Technical Reports Server [NTRS] Meador, Mary Ann B.; Johnston, J. Christopher; Cavano, Paul J. 1997-01-01 Solid NMR of C-13 isotope-labeled samples of PMR-15 was used to follow the cross-linking reaction of the nadic end cap. Some samples were labeled on one of the carbon atoms of the nadic end cap, and others on the methylene carbon atom of the methylenedianiline portion of the polymer. NMR spectra were run on these samples both before and after cross-linking. In this way, direct evidence of the major products of cross-linking under normal cure conditions is provided. The majority [approximately 85%] of the cross-linking derives from olefin polymerization through the double bond of the end cap. Approximately 15% of the products could come from a pathway involving a retro-Diels-Alder reaction. However, all of the products could be explained by a biradical intermediate without a retro-Diels-Alder reaction. Evidence is also presented that the methylene moiety in the methylenedianiline part of the polymer chain also participates in the cross-linking, albeit to a small extent, by a radical transfer reaction. Different cure conditions [higher temperatures, longer times] could change the relative distribution of the products.
2. Substrate Trapping in Crystals of the Thiolase OleA Identifies Three Channels That Enable Long Chain Olefin Biosynthesis. PubMed Goblirsch, Brandon R; Jensen, Matthew R; Mohamed, Fatuma A; Wackett, Lawrence P; Wilmot, Carrie M 2016-12-23 Phylogenetically diverse microbes that produce long chain, olefinic hydrocarbons have received much attention as possible sources of renewable energy biocatalysts. One enzyme that is critical for this process is OleA, a thiolase superfamily enzyme that condenses two fatty acyl-CoA substrates to produce a β-ketoacid product and initiates the biosynthesis of long chain olefins in bacteria. Thiolases typically utilize a ping-pong mechanism centered on an active site cysteine residue. Reaction with the first substrate produces a covalent cysteine-thioester tethered acyl group that is transferred to the second substrate through formation of a carbon-carbon bond. Although the basics of thiolase chemistry are precedented, the mechanism by which OleA accommodates two substrates with extended carbon chains and a coenzyme moiety-unusual for a thiolase-are unknown. Gaining insights into this process could enable manipulation of the system for large scale olefin production with hydrocarbon chains lengths equivalent to those of fossil fuels. In this study, mutagenesis of the active site cysteine in Xanthomonas campestris OleA [Cys 143 ] enabled trapping of two catalytically relevant species in crystals. In the resulting structures, long chain alkyl groups [C 12 and C 14 ] and phosphopantetheinate define three substrate channels in a T-shaped configuration, explaining how OleA coordinates its two substrates and product. The C143A OleA co-crystal structure possesses a single bound acyl-CoA representing the Michaelis complex with the first substrate, whereas the C143S co-crystal structure contains both acyl-CoA and fatty acid, defining how a second substrate binds to the acyl-enzyme intermediate. An active site glutamate [Gluβ 117 ] is positioned to deprotonate bound acyl-CoA and initiate carbon-carbon bond formation. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.
3. Substrate Trapping in Crystals of the Thiolase OleA Identifies Three Channels That Enable Long Chain Olefin Biosynthesis* PubMed Central Goblirsch, Brandon R.; Jensen, Matthew R.; Mohamed, Fatuma A.; Wackett, Lawrence P.; Wilmot, Carrie M. 2016-01-01 Phylogenetically diverse microbes that produce long chain, olefinic hydrocarbons have received much attention as possible sources of renewable energy biocatalysts. One enzyme that is critical for this process is OleA, a thiolase superfamily enzyme that condenses two fatty acyl-CoA substrates to produce a β-ketoacid product and initiates the biosynthesis of long chain olefins in bacteria. Thiolases typically utilize a ping-pong mechanism centered on an active site cysteine residue. Reaction with the first substrate produces a covalent cysteine-thioester tethered acyl group that is transferred to the second substrate through formation of a carbon-carbon bond. Although the basics of thiolase chemistry are precedented, the mechanism by which OleA accommodates two substrates with extended carbon chains and a coenzyme moiety—unusual for a thiolase—are unknown. Gaining insights into this process could enable manipulation of the system for large scale olefin production with hydrocarbon chains lengths equivalent to those of fossil fuels. In this study, mutagenesis of the active site cysteine in Xanthomonas campestris OleA [Cys143] enabled trapping of two catalytically relevant species in crystals. In the resulting structures, long chain alkyl groups [C12 and C14] and phosphopantetheinate define three substrate channels in a T-shaped configuration, explaining how OleA coordinates its two substrates and product. The C143A OleA co-crystal structure possesses a single bound acyl-CoA representing the Michaelis complex with the first substrate, whereas the C143S co-crystal structure contains both acyl-CoA and fatty acid, defining how a second substrate binds to the acyl-enzyme intermediate. An active site glutamate [Gluβ117] is positioned to deprotonate bound acyl-CoA and initiate carbon-carbon bond formation. PMID:27815501
4. Substrate Trapping in Crystals of the Thiolase OleA Identifies Three Channels That Enable Long Chain Olefin Biosynthesis DOE Office of Scientific and Technical Information [OSTI.GOV] Goblirsch, Brandon R.; Jensen, Matthew R.; Mohamed, Fatuma A. Phylogenetically diverse microbes that produce long chain, olefinic hydrocarbons have received much attention as possible sources of renewable energy biocatalysts. One enzyme that is critical for this process is OleA, a thiolase superfamily enzyme that condenses two fatty acyl-CoA substrates to produce a β-ketoacid product and initiates the biosynthesis of long chain olefins in bacteria. Thiolases typically utilize a ping-pong mechanism centered on an active site cysteine residue. Reaction with the first substrate produces a covalent cysteine-thioester tethered acyl group that is transferred to the second substrate through formation of a carbon-carbon bond. Although the basics of thiolase chemistry aremore » precedented, the mechanism by which OleA accommodates two substrates with extended carbon chains and a coenzyme moiety—unusual for a thiolase—are unknown. Gaining insights into this process could enable manipulation of the system for large scale olefin production with hydrocarbon chains lengths equivalent to those of fossil fuels. In this study, mutagenesis of the active site cysteine in Xanthomonas campestris OleA [Cys143] enabled trapping of two catalytically relevant species in crystals. In the resulting structures, long chain alkyl groups [C12 and C14] and phosphopantetheinate define three substrate channels in a T-shaped configuration, explaining how OleA coordinates its two substrates and product. The C143A OleA co-crystal structure possesses a single bound acyl-CoA representing the Michaelis complex with the first substrate, whereas the C143S co-crystal structure contains both acyl-CoA and fatty acid, defining how a second substrate binds to the acyl-enzyme intermediate. An active site glutamate [Gluβ117] is positioned to deprotonate bound acyl-CoA and initiate carbon-carbon bond formation.« less
5. Effect of Polymer Electrode Morphology on Performance of a Lithium/Polypyrrole Battery. M.S. Thesis NASA Technical Reports Server [NTRS] Nicholson, Marjorie Anne 1991-01-01 A variety of conducting polymer batteries were described in the recent literature. In this work, a Li/Polypyrrole secondary battery is described. The effect of controlling the morphology of the polymer on enhancement of counterion diffusion in the polymer phase is explored. A method of preparing conducting polymers was developed which yields high surface area per unit volume of electrode material. A porous membrane is used as a template in which to electrochemically polymerize pyrrole, then the membrane is dissolved, leaving the polymer in a fibrillar form. Conventionally, the polymer is electrochemically polymerized as a dense polymer film on a smooth Pt disk electrode. Previous work has shown that when the polymer is electrochemically polymerized in fribrillar form, charge transport rates are faster and charge capacities are greater than for dense, conventionally grown films containing the same amount of polymer. The purpose is to expand previous work by further investigating the possibilities of the optimization of transport rates in polypyrrole films by controlling the morphology of the films. The utility of fibrillar polypyrrole as a cathode material in a lithium/polymer secondary battery is then assessed. The performance of the fibrillar battery is compared to the performance of an analogous battery which employed a conventionally grown polypyrrole film. The study includes a comparison of cyclic voltammetry, shape of charge/discharge curves, discharge time and voltage, cycle life, coulombic efficiencies, charge capacities, energy densities, and energy efficiencies.
6. Integrated Electrochemical Processes for CO 2 Capture and Conversion to Commodity Chemicals DOE Office of Scientific and Technical Information [OSTI.GOV] Hatton, T. Alan; Jamison, Timothy 2013-09-30 The Massachusetts Institute of Technology [MIT] and Siemens Corporations [SCR] are developing new chemical synthesis processes for commodity chemicals from CO 2. The process is assessed as a novel chemical sequestration technology that utilizes CO 2 from dilute gas streams generated at industrial carbon emitters as a raw material to produce useful commodity chemicals. Work at Massachusetts Institute of Technology [MIT] commenced on October 1st, 2010, and finished on September 30th, 2013. During this period, we have investigated and accomplished five objectives that mainly focused on converting CO 2 into high-value chemicals: 1] Electrochemical assessment of catalytic transformation of COmore » 2 and epoxides to cyclic carbonates; 2] Investigation of organocatalytic routes to convert CO 2 and epoxide to cyclic carbonates; 3] Investigation of CO 2 Capture and conversion using simple olefins under continuous flow; 4] Microwave assisted synthesis of cyclic carbonates from olefins using sodium bicarbonates in a green pathway; 5] Life cycle analyses of integrated chemical sequestration process. In this final report, we will describe the detailed study performed during the three year period and findings and conclusions drawn from our research.« less
7. Electrodeposition of polymer electrolyte in nanostructured electrodes for enhanced electrochemical performance of thin-film Li-ion microbatteries NASA Astrophysics Data System [ADS] Salian, Girish D.; Lebouin, Chrystelle; Demoulin, A.; Lepihin, M. S.; Maria, S.; Galeyeva, A. K.; Kurbatov, A. P.; Djenizian, Thierry 2017-02-01 We report that electrodeposition of polymer electrolyte in nanostructured electrodes has a strong influence on the electrochemical properties of thin-film Li-ion microbatteries. Electropolymerization of PMMA-PEG [polymethyl methacrylate-polyethylene glycol] was carried out on both the anode [self-supported titania nanotubes] and the cathode [porous LiNi0.5Mn1.5O4] by cyclic voltammetry and the resulting electrode-electrolyte interface was examined by scanning electron microscopy. The electrochemical characterizations performed by galvanostatic experiments reveal that the capacity values obtained at different C-rates are doubled when the electrodes are completely filled by the polymer electrolyte.
8. Oil-in-oil emulsions: a unique tool for the formation of polymer nanoparticles. PubMed Klapper, Markus; Nenov, Svetlin; Haschick, Robert; Müller, Kevin; Müllen, Klaus 2008-09-01 Polymer latex particles are nanofunctional materials with widespread applications including electronics, pharmaceuticals, photonics, cosmetics, and coatings. These materials are typically prepared using waterborne heterogeneous systems such as emulsion, miniemulsion, and suspension polymerization. However, all of these processes are limited to water-stable catalysts and monomers mainly polymerizable via radical polymerization. In this Account, we describe a method to overcome this limitation: nonaqueous emulsions can serve as a versatile tool for the synthesis of new types of polymer nanoparticles. To form these emulsions, we first needed to find two nonmiscible nonpolar/polar aprotic organic solvents. We used solvent mixtures of either DMF or acetonitrile in alkanes and carefully designed amphiphilic block and statistical copolymers, such as polyisoprene- b-poly[methyl methacrylate] [PI- b-PMMA], as additives to stabilize these emulsions. Unlike aqueous emulsions, these new emulsion systems allowed the use of water-sensitive monomers and catalysts. Although polyaddition and polycondensation reactions usually lead to a large number of side products and only to oligomers in the aqueous phase, these new conditions resulted in high-molecular-weight, defect-free polymers. Furthermore, conducting nanoparticles were produced by the iron[III]-induced synthesis of poly[ethylenedioxythiophene] [PEDOT] in an emulsion of acetonitrile in cyclohexane. Because metallocenes are sensitive to nitrile and carbonyl groups, the acetonitrile and DMF emulsions were not suitable for carrying out metallocene-catalyzed olefin polymerization. Instead, we developed a second system, which consists of alkanes dispersed in perfluoroalkanes. In this case, we designed a new amphipolar polymeric emulsifier with fluorous and aliphatic side chains to stabilize the emulsions. Such heterogeneous mixtures facilitated the catalytic polymerization of ethylene or propylene to give spherical nanoparticles
9. Virtual screening using combinatorial cyclic peptide libraries reveals protein interfaces readily targetable by cyclic peptides. PubMed Duffy, Fergal J; O'Donovan, Darragh; Devocelle, Marc; Moran, Niamh; O'Connell, David J; Shields, Denis C 2015-03-23 Protein-protein and protein-peptide interactions are responsible for the vast majority of biological functions in vivo, but targeting these interactions with small molecules has historically been difficult. What is required are efficient combined computational and experimental screening methods to choose among a number of potential protein interfaces worthy of targeting lead macrocyclic compounds for further investigation. To achieve this, we have generated combinatorial 3D virtual libraries of short disulfide-bonded peptides and compared them to pharmacophore models of important protein-protein and protein-peptide structures, including short linear motifs [SLiMs], protein-binding peptides, and turn structures at protein-protein interfaces, built from 3D models available in the Protein Data Bank. We prepared a total of 372 reference pharmacophores, which were matched against 108,659 multiconformer cyclic peptides. After normalization to exclude nonspecific cyclic peptides, the top hits notably are enriched for mimetics of turn structures, including a turn at the interaction surface of human α thrombin, and also feature several protein-binding peptides. The top cyclic peptide hits also cover the critical "hot spot" interaction sites predicted from the interaction crystal structure. We have validated our method by testing cyclic peptides predicted to inhibit thrombin, a key protein in the blood coagulation pathway of important therapeutic interest, identifying a cyclic peptide inhibitor with lead-like activity. We conclude that protein interfaces most readily targetable by cyclic peptides and related macrocyclic drugs may be identified computationally among a set of candidate interfaces, accelerating the choice of interfaces against which lead compounds may be screened.
10. Electrochemical synthesis of Sm2O3 nanoparticles: Application in conductive polymer composite films for supercapacitors. PubMed Mohammad Shiri, Hamid; Ehsani, Ali; Jalali Khales, Mina 2017-11-01 A novel electrosynthetic method was introduced to synthesize of Sm 2 O 3 nanoparticles and furthermore, for improving the electrochemical performance of conductive polymer, hybrid POAP/Sm 2 O 3 films have then been fabricated by POAP electropolymerization in the presence of Sm 2 O 3 nanoparticles as active electrodes for electrochemical supercapacitors. The structure, morphology, chemical composition of Sm 2 O 3 nanoparticles was examined. Surface and electrochemical analyses have been used for characterization of Sm 2 O 3 and POAP/Sm 2 O 3 composite films. Different electrochemical methods including galvanostatic charge discharge experiments, cyclic voltammetry and electrochemical impedance spectroscopy have been applied to study the system performance. The supercapacity behavior of the composite film was attributed to the [i] high active surface area of the composite, [ii] charge transfer along the polymer chain due to the conjugation form of the polymer and finally [iii] synergism effect between conductive polymer and Sm 2 O 3 nanoparticles. Copyright © 2017 Elsevier Inc. All rights reserved.
11. Cyclic behavior, development, and characteristics of a ductile hybrid fiber-reinforced polymer [DHFRP] for reinforced concrete members NASA Astrophysics Data System [ADS] Hampton, Francis Patrick Reinforced concrete [R/C] structures especially pavements and bridge decks that constitute vital elements of the infrastructure of all industrialized societies are deteriorating prematurely. Structural repair and upgrading of these structural elements have become a more economical option for constructed facilities especially in the United States and Canada. One method of retrofitting concrete structures is the use of advanced materials. Fiber reinforced polymer [FRP] composite materials typically are in the form of fabric sheets or reinforcing bars. While the strength and stiffness of the FRP is high, composites are inherently brittle, with limited or no ductility. Conventional FRP systems cannot currently meet ductility demand, and therefore, may fail in a catastrophic failure mode. The primary goal of this research was to develop an optimized prototype 10-mm diameter DHFRP bar. The behavior of the bar under full load reversals to failure was investigated. However, this bar first needed to be designed and manufactured in the Fibrous Materials Research at Drexel University. Material properties were determined through testing to categorize the strength properties of the DHFRP. Similitude was used to demonstrate the scaling of properties from the original model bars. The four most important properties of the DHFRP bars are sufficient strength and stiffness, significant ductility for plasticity to develop in the R/C section, and sufficient bond strength for the R/C section to develop its full strength. Once these properties were determined the behavior of reinforced concrete members was investigated. This included the testing of prototype-size beams under monotonic loading and model and prototype beam-columns under reverse cyclic loading. These tests confirmed the large ductility exhibited by the DHFRP. Also the energy absorption capacity of the bar was demonstrated by the hysteretic behavior of the beam-columns. Displacement ductility factors in the range of 3
12. Catalytical Photocyclization of Arylamines with a-Olefins in the Synthesis of 2-Alkylquinoline ERIC Educational Resources Information Center Makhmutov, Aynur; Usmanov, Salavat; Mustafin, Ahat 2016-01-01 The article deals with the results of investigation of the process of catalytical photocyclization of aniline and aniline hydrochloride with a-olefins [hexene-1, heptene-1 and octene-1]. The following compounds of d- and f-metals are tested as probable catalysts: CuSO4•5H2O, EuCl3•6H2O, PrCl3•6H2O, TbCl3•6H2O, La2O3, MnO2, NiSO4•6H2O, NiCl2•6H2O,…
13. Synthesis of all-hydrocarbon stapled α-helical peptides by ring-closing olefin metathesis. PubMed Kim, Young-Woo; Grossmann, Tom N; Verdine, Gregory L 2011-06-01 This protocol provides a detailed procedure for the preparation of stapled α-helical peptides, which have proven their potential as useful molecular probes and as next-generation therapeutics. Two crucial features of this protocol are [i] the construction of peptide substrates containing hindered α-methyl, α-alkenyl amino acids and [ii] the ring-closing olefin metathesis [RCM] of the resulting resin-bound peptide substrates. The stapling systems described in this protocol, namely bridging one or two turns of an α-helix, are highly adaptable to most peptide sequences, resulting in favorable RCM kinetics, helix stabilization and promotion of cellular uptake.
14. Synthesis and Catalytic Activity of Ruthenium-Indenylidene Complexes for Olefin Metathesis: Microscale Experiments for the Undergraduate Inorganic or Organometallic Laboratories ERIC Educational Resources Information Center Pappenfus, Ted M.; Hermanson, David L.; Ekerholm, Daniel P.; Lilliquist, Stacie L.; Mekoli, Megan L. 2007-01-01 A series of experiments for undergraduate laboratory courses [e.g., inorganic, organometallic or advanced organic] have been developed. These experiments focus on understanding the design and catalytic activity of ruthenium-indenylidene complexes for olefin metathesis. Included in the experiments are the syntheses of two ruthenium-indenylidene…
15. Functionalized SBA-15 supported nickel [II]–oxime–imine catalysts for liquid phase oxidation of olefins under solvent-free conditions DOE Office of Scientific and Technical Information [OSTI.GOV] Paul, Luna; Banerjee, Biplab; Bhaumik, Asim, E-mail: msab@iacs.res.in 2016-05-15 A new oxime–imine functionalized highly ordered mesoporous SBA-15 [SBA-15-NH{sub 2}-DAMO] has been synthesized via post-synthesis functionalization of SBA-15 with 3-aminopropyl-triethoxysilane followed by the Schiff base condensation with diacetylmonooxime, which was further reacted with Ni[ClO{sub 4}]{sub 2} to yield the functionalized nickel catalyst SBA-15-NH{sub 2}-DAMO-Ni. All the synthesized materials were thoroughly characterized using different characterization techniques. It was found that SBA-15-NH{sub 2}-DAMO-Ni catalyzes the one-pot oxidation of olefins like styrene, cyclohexene, cyclooctene, 1-hexene and 1-octene to the corresponding benzaldehyde, cyclohexene-1-ol and cyclooctene-oxide, respectively under solvent-free conditions by using tert-butylhydroperoxide as oxidant. - Graphical abstract: A new well characterized oxime–imine functionalized highlymore » ordered mesoporous SBA-15-NH{sub 2}-DAMO-Ni complex catalyzes the one-pot oxidation of olefins under solvent free mild conditions.« less
16. Organocatalytic sequential alpha-amination-Horner-Wadsworth-Emmons olefination of aldehydes: enantioselective synthesis of gamma-amino-alpha,beta-unsaturated esters. PubMed Kotkar, Shriram P; Chavan, Vilas B; Sudalai, Arumugam 2007-03-15 A novel and highly enantioselective method for the synthesis of gamma-amino-alpha,beta-unsaturated esters via tandem alpha-amination-Horner-Wadsworth-Emmons [HWE] olefination of aldehydes is described. The one-pot assembly has been demonstrated for the construction of functionalized chiral 2-pyrrolidones, subunits present in several alkaloids. [structure: see text
17. Chiral imidate-ferrocenylphosphanes: synthesis and application as P,N-ligands in iridium[I]-catalyzed hydrogenation of unfunctionalized and poorly functionalized olefins. PubMed Bert, Katrien; Noël, Timothy; Kimpe, Wim; Goeman, Jan L; Van der Eycken, Johan 2012-11-14 A small library of chiral imidate-ferrocenylphosphane ligands was efficiently synthesized [8 examples] and evaluated in the iridium[I]-catalyzed hydrogenation of unfunctionalized and poorly functionalized olefins. These catalysts perform very well in a range of examples [yields and ee's up to 100%].
18. Effect of Steam Deactivation Severity of ZSM-5 Additives on LPG Olefins Production in the FCC Process. PubMed Gusev, Andrey A; Psarras, Antonios C; Triantafyllidis, Konstantinos S; Lappas, Angelos A; Diddams, Paul A 2017-10-21 ZSM-5-containing catalytic additives are widely used in oil refineries to boost light olefin production and improve gasoline octanes in the Fluid Catalytic Cracking [FCC] process. Under the hydrothermal conditions present in the FCC regenerator [typically >700 °C and >8% steam], FCC catalysts and additives are subject to deactivation. Zeolites [e.g., Rare Earth USY in the base catalyst and ZSM-5 in Olefins boosting additives] are prone to dealumination and partial structural collapse, thereby losing activity, micropore surface area, and undergoing changes in selectivity. Fresh catalyst and additives are added at appropriate respective levels to the FCC unit on a daily basis to maintain overall targeted steady-state [equilibrated] activity and selectivity. To mimic this process under accelerated laboratory conditions, a commercial P/ZSM-5 additive was hydrothermally equilibrated via a steaming process at two temperatures: 788 °C and 815 °C to simulate moderate and more severe equilibration industrial conditions, respectively. n -Dodecane was used as probe molecule and feed for micro-activity cracking testing at 560 °C to determine the activity and product selectivity of fresh and equilibrated P-doped ZSM-5 additives. The fresh/calcined P/ZSM-5 additive was very active in C 12 cracking while steaming limited its activity, i.e., at catalyst-to-feed [C/F] ratio of 1, about 70% and 30% conversion was obtained with the fresh and steamed additives, respectively. A greater activity drop was observed upon increasing the hydrothermal deactivation severity due to gradual decrease of total acidity and microporosity of the additives. However, this change in severity did not result in any selectivity changes for the LPG [liquefied petroleum gas] olefins as the nature [Brønsted-to-Lewis ratio] of the acid/active sites was not significantly altered upon steaming. Steam deactivation of ZSM-5 had also no significant effect on aromatics formation which was enhanced at higher
19. Hollow waveguide for giant Er:YAG laser pulses transfer NASA Astrophysics Data System [ADS] Nemec, Michal; Jelinkova, Helena; Koranda, Petr; Cech, Miroslav; Sulc, Jan; Miyagi, Mitsunobu; Shi, Yi-Wei; Matsuura, Yuji 2004-06-01 Short Er:YAG laser pulses were delivered by a cyclic olefin polymer coated silver hollow glass [COP/Ag] waveguide specially designed for a high power radiation. Er:YAG laser was Q-switched by an electro-optic shutter - LiNbO3 Pockels cell with Brewster angle cut input/output faces. The maximum energy output obtained from this system was 29 mJ with the length of pulse 69 ns corresponding to 420 kW output peak power. The system was working with the repetition rate of 1.5 Hz. A delivery system composed of a lens [f = 40 mm], protector and waveguide with the 700/850 μm diameter and 50 cm or 1 m length. The measured maximum delivered intensity was 86 MW/cm2 what corresponds to the transmission of 78.6 % for whole delivery system. Using of a sealed cap, this delivery system gives a possibility of the contact surgical treatment in many medicine branches, for example ophthalmology, urology or dentistry.
20. Sequential shrink photolithography for plastic microlens arrays PubMed Central Dyer, David; Shreim, Samir; Jayadev, Shreshta; Lew, Valerie; Botvinick, Elliot; Khine, Michelle 2011-01-01 Endeavoring to push the boundaries of microfabrication with shrinkable polymers, we have developed a sequential shrink photolithography process. We demonstrate the utility of this approach by rapidly fabricating plastic microlens arrays. First, we create a mask out of the children’s toy Shrinky Dinks by simply printing dots using a standard desktop printer. Upon retraction of this pre-stressed thermoplastic sheet, the dots shrink to a fraction of their original size, which we then lithographically transfer onto photoresist-coated commodity shrink wrap film. This shrink film reduces in area by 95% when briefly heated, creating smooth convex photoresist bumps down to 30 µm. Taken together, this sequential shrink process provides a complete process to create microlenses, with an almost 99% reduction in area from the original pattern size. Finally, with a lithography molding step, we emboss these bumps into optical grade plastics such as cyclic olefin copolymer for functional microlens arrays. PMID:21863126

1. Influence of the Reaction Temperature on the Nature of the Active and Deactivating Species During Methanol-to-Olefins Conversion over H-SAPO-34 PubMed Central 2017-01-01 The selectivity toward lower olefins during the methanol-to-olefins conversion over H-SAPO-34 at reaction temperatures between 573 and 773 K has been studied with a combination of operando UV–vis diffuse reflectance spectroscopy and online gas chromatography. It was found that the selectivity toward propylene increases in the temperature range of 573–623 K, while it decreases in the temperature range of 623–773 K. The high degree of incorporation of olefins, mainly propylene, into the hydrocarbon pool affects the product selectivity at lower reaction temperatures. The nature and dynamics of the active and deactivating hydrocarbon species with increasing reaction temperature were revealed by a non-negative matrix factorization of the time-resolved operando UV–vis diffuse reflectance spectra. The active hydrocarbon pool species consist of mainly highly methylated benzene carbocations at temperatures between 573 and 598 K, of both highly methylated benzene carbocations and methylated naphthalene carbocations at 623 K, and of only methylated naphthalene carbocations at temperatures between 673 and 773 K. The operando spectroscopy results suggest that the nature of the active species also influences the olefin selectivity. In fact, monoenylic and highly methylated benzene carbocations are more selective to the formation of propylene, whereas the formation of the group of low methylated benzene carbocations and methylated naphthalene carbocations at higher reaction temperatures [i.e., 673 and 773 K] favors the formation of ethylene. At reaction temperatures between 573 and 623 K, catalyst deactivation is caused by the gradual filling of the micropores with methylated naphthalene carbocations, while between 623 and 773 K the formation of neutral poly aromatics and phenanthrene/anthracene carbocations are mainly responsible for catalyst deactivation, their respective contribution increasing with increasing reaction temperature. Methanol pulse experiments at
2. 'All-solid-state' electrochemistry of a protein-confined polymer electrolyte film DOE Office of Scientific and Technical Information [OSTI.GOV] Parthasarathy, Meera; Pillai, Vijayamohanan K.; Mulla, Imtiaz S. 2007-12-07 Interfacial redox behavior of a heme protein [hemoglobin] confined in a solid polymer electrolyte membrane, Nafion [a perfluoro sulfonic acid ionomer] is investigated using a unique 'all-solid-state' electrochemical methodology. The supple phase-separated structure of the polymer electrolyte membrane, with hydrophilic pools containing solvated protons and water molecules, is found to preserve the incorporated protein in its active form even in the solid-state, using UV-visible, Fluorescence [of Tryptophan and Tyrosine residues] and DRIFT [diffuse reflectance infrared Fourier transform] spectroscopy. More specifically, solid-state cyclic voltammetry and electrochemical impedance of the protein-incorporated polymer films reveal that the Fe{sup 2+}-form of the entrapped proteinmore » is found to bind molecular oxygen more strongly than the native protein. In the 'all-solid-state' methodology, as there is no need to dip the protein-modified electrode in a liquid electrolyte [like the conventional electrochemical methods], it offers an easier means to study a number of proteins in a variety of polymer matrices [even biomimetic assemblies]. In addition, the results of the present investigation could find interesting application in a variety of research disciplines, in addition to its fundamental scientific interest, including protein biotechnology, pharmaceutical and biomimetic chemistry.« less
3. Molybdenum chloride catalysts for Z-selective olefin metathesis reactions NASA Astrophysics Data System [ADS] Koh, Ming Joo; Nguyen, Thach T.; Lam, Jonathan K.; Torker, Sebastian; Hyvl, Jakub; Schrock, Richard R.; Hoveyda, Amir H. 2017-01-01 The development of catalyst-controlled stereoselective olefin metathesis processes has been a pivotal recent advance in chemistry. The incorporation of appropriate ligands within complexes based on molybdenum, tungsten and ruthenium has led to reactivity and selectivity levels that were previously inaccessible. Here we show that molybdenum monoaryloxide chloride complexes furnish higher-energy [Z] isomers of trifluoromethyl-substituted alkenes through cross-metathesis reactions with the commercially available, inexpensive and typically inert Z-1,1,1,4,4,4-hexafluoro-2-butene. Furthermore, otherwise inefficient and non-stereoselective transformations with Z-1,2-dichloroethene and 1,2-dibromoethene can be effected with substantially improved efficiency and Z selectivity. The use of such molybdenum monoaryloxide chloride complexes enables the synthesis of representative biologically active molecules and trifluoromethyl analogues of medicinally relevant compounds. The origins of the activity and selectivity levels observed, which contradict previously proposed principles, are elucidated with the aid of density functional theory calculations.
4. Ionic-liquid mediated olefin hydroboration and heteroatom insertion reactions, and the development of template routes to non-oxide ceramic nano- and micro-structures NASA Astrophysics Data System [ADS] Kusari, Upal The goal of the work described in this dissertation was two-fold: [1] To use the unique properties of ionic liquids to develop new synthetic routes to boron-containing molecules including substituted decaboranes, ortho-carboranes and chalcogeno-boranes, and [2] to combine newly developed chemical precursors with template routes to fabricate the non-oxide ceramics boron carbide, silicon carbide and boron nitride on the micro- and nano-scales. The first application of ionic liquid and related salt systems to the hydroboration of a variety of olefins with the polyborane cage B10H 14, leading to the syntheses of functionalized decaborane clusters, 6-R-B10H13, was demonstrated. The decaborane olefin-hydroboration reaction was found to proceed with a wide variety of functional olefins, including, alkenyl, halide, phenyl, ether, ester, pinacolborane, ketone and alcohol-containing olefins. These reactions provide a general, simple, one-pot and high-yield alternative route to functional boranes. The functional decaboranes were then converted by another ionic liquid mediated reaction, to its ortho -carborane derivatives 3-R-1,2-Et2C2B 10H9. Experimental and computational studies of the hydroboration mechanism suggest that the ionic liquid induced the formation of the B 10H13- anion which behaved as an electrophile in the olefin-hydroboration reaction. The unique properties of ionic liquids were also found to be useful in mediating the insertion of chalcogen heteroatoms into the borane clusters nido-B10H14, nido-5,6-C2B8H12 and arachno -4-CB8H14 and led to the improved syntheses of the known compounds nido-7-SB10H12, nido-7-SeB10H12, nido-7,9,10-SC 2B8H10, nido-7,9,10-SeC 2B8H10 and arachno-6,9-CSB 8H12, as well as the synthesis of the new 10-vertex selena-monocarbaborane arachno-6,9-CSeB8H12 [˜40% yield]. The second part of the thesis demonstrated that newly developed chemical precursors can be used in conjunction with silica bead and diatom frustule templates to generate
5. Conducting Polymer Coated Graphene Oxide Electrode for Rechargeable Lithium-Sulfur Batteries. PubMed Lee, Hee-Yoon; Jung, Yongju; Kim, Seok 2016-03-01 Poly[diallyldimethylammonium chloride] [PDDA]/graphene oxide-sulfur composites were prepared by a chemical oxidation method. For the PDDA-GO composites, conducting polymers [PDDA] were coated on the surface of GO sheets. PDDA-GO composites could be expected to increase electrical conductivity and protect restacking of graphene sheets. And then, sulfur particles were dispersed into the PDDA-GO composites by mixing in the CS2 solvent. It is expected the PDDA-GO/S composites show the limited release of polysulfides due to the fact that it can provide high surface area, because conducting polymer can be used as spacer between graphene sheets. Electrochemical performances of prepared composites were characterized by cyclic voltammetry [CV]. The PDDA-GO/S composites showed a high discharge capacity of 1102 mAh g[-1] at the first cycle and a good cycle retention of 60% after 100 cycles.
6. Lithium-Polymer battery based on polybithiophene as cathode material NASA Astrophysics Data System [ADS] Chen, J.; Wang, J.; Wang, C.; Too, C. O.; Wallace, G. G. Stainless-steel mesh electrodes coated with polybithiophene, obtained by electrochemical polymerization [constant potential and constant current], have been investigated as cathode materials in a lithium-polybithiophene rechargeable battery by cyclic voltammetry, electrochemical impedance spectroscopy and long-term charge-discharge cycling process. The effects of different growth methods on the surface morphology of the films and the charge-discharge capacity are discussed in detail. The results show that polybithiophene-hexafluorophosphate is a very promising cathode material for manufacturing lithium-polymer rechargeable batteries with a highly stable discharge capacity of 81.67 mAh g -1 after 50 cycles.
7. Solid-state radioluminescent compositions DOEpatents Clough, Roger L.; Gill, John T.; Hawkins, Daniel B.; Renschler, Clifford L.; Shepodd, Timothy J.; Smith, Henry M. 1991-01-01 A solid state radioluminescent composition for light source comprises an optically clear polymer organic matrix containing tritiated organic materials and dyes capable of "red" shifting primary scintillation emissions from the polymer matrix. The tritiated organic materials are made by reducing, with tritium, an unsaturated organic compound that prior to reduction contains olefinic or alkynylic bonds.
8. The influence of TiO2 composition in LiBOB electrolyte polymer composite membrane characteristics for lithium ion batteries applications NASA Astrophysics Data System [ADS] Lestariningsih, T.; Sabrina, Q.; Wigayati, E. M. 2018-03-01 Characterization of the composite membrane of LiBOB electrolyte polymers made from poly [vinylidene fluoride co-hexafluororopylene] [PVdF-HFP] as the polymer, LiBOB or LiB[C2O4]2 as electrolyte salt and titanium dioxide [TiO2] as ceramic filler of three different concentrations have been done. Sample of membrane was prepared using solution casting technique. Microstructural study by SEM shows non-uniform distribution of pore over the surface of the sample. X-ray structural analysis, impedance spectroscopy, and cyclic voltammetry [CV] studies were carried out. Membrane composite polymer of LiBOB electrolyte without additional ceramic filler with composition of 70% polymer, 30% LiBOB, and 0% TiO2 has the greatest conductivity for forming amorphous phase and is compatible with material membrane composite. Meanwhile, sample with 70% polymer composition, 28% LiBOB and 2% TiO2 shows oxidation reaction at the most perfect discharge despite very slow current speed.
9. PHENANTHROLINE-STABILIZED PALLADIUM NANOPARTICLES IN POLYETHYLENE GLYCOL—AN ACTIVE AND RECYCLABLE CATALYST SYSTEM FOR THE SELECTIVE HYDROGENATION OF OLEFINS USING MOLECULAR HYDROGEN EPA Science Inventory 1,10-Phenanthroline-stabilized palladium nanoparticles dispersed in a polyethylene glycol [PEG] matrix is synthesized which is found to be a stable and active catalyst for the selective hydrogenation of olefins using molecular hydrogen under mild reaction conditions. A variety of...
10. Cyclic tensile strain and cyclic hydrostatic pressure differentially regulate expression of hypertrophic markers in primary chondrocytes. PubMed Wong, Marcy; Siegrist, Mark; Goodwin, Kelly 2003-10-01 Endochondral ossification is regulated by many factors, including mechanical stimuli, which can suppress or accelerate chondrocyte maturation. Mathematical models of endochondral ossification have suggested that tension [or shear stress] can accelerate the formation of endochondral bone, while hydrostatic stress preserves the cartilage phenotype. The goal of this study was to test this hypothesis by examining the expression of hypertrophic chondrocyte markers [transcription factor Cbfa1, MMP-13, type X collagen, VEGF, CTGF] and cartilage matrix proteins under cyclic tension and cyclic hydrostatic pressure. Chondrocyte-seeded alginate constructs were exposed to one of the two loading modes for a period of 3 h per day for 3 days. Gene expression was analyzed using real-time RT-PCR. Cyclic tension upregulated the expression of Cbfa1, MMP-13, CTGF, type X collagen and VEGF and downregulated the expression of TIMP-1. Cyclic tension also upregulated the expression of type 2 collagen, COMP and lubricin, but did not change the expression of SOX9 and aggrecan. Cyclic hydrostatic pressure downregulated the expression of MMP-13 and type I collagen and upregulated expression of TIMP-1 compared to the unloaded controls. Hydrostatic pressure may slow chondrocyte differentiation and have a chondroprotective, anti-angiogenic influence on cartilage tissue. Our results suggest that cyclic tension activates the Cbfa1/MMP-13 pathway and increases the expression of terminal differentiation hypertrophic markers. Mammalian chondrocytes appear to have evolved complex mechanoresponsive mechanisms, the effects of which can be observed in the histomorphologic establishment of the cartilaginous skeleton during development and maturation.
11. Statistical damage constitutive model for rocks subjected to cyclic stress and cyclic temperature NASA Astrophysics Data System [ADS] Zhou, Shu-Wei; Xia, Cai-Chu; Zhao, Hai-Bin; Mei, Song-Hua; Zhou, Yu 2017-10-01 A constitutive model of rocks subjected to cyclic stress-temperature was proposed. Based on statistical damage theory, the damage constitutive model with Weibull distribution was extended. Influence of model parameters on the stress-strain curve for rock reloading after stress-temperature cycling was then discussed. The proposed model was initially validated by rock tests for cyclic stress-temperature and only cyclic stress. Finally, the total damage evolution induced by stress-temperature cycling and reloading after cycling was explored and discussed. The proposed constitutive model is reasonable and applicable, describing well the stress-strain relationship during stress-temperature cycles and providing a good fit to the test results. Elastic modulus in the reference state and the damage induced by cycling affect the shape of reloading stress-strain curve. Total damage induced by cycling and reloading after cycling exhibits three stages: initial slow increase, mid-term accelerated increase, and final slow increase.
12. A Single Molecular Diels-Alder Crosslinker for Achieving Recyclable Cross-Linked Polymers. PubMed Chen, Shengli; Wang, Fenfen; Peng, Yongjin; Chen, Tiehong; Wu, Qiang; Sun, Pingchuan 2015-09-01 A triol-functional crosslinker combining the thermoreversible properties of Diels-Alder [DA] adducts in one molecule is designed, synthesized, and used as an ideal substitute of a traditional crosslinker to prepare thermal recyclable cross-linked polyurethanes with excellent mechanical properties and recyclability in a very simple and efficient way. The recycle property of these materials achieved by the DA/retro-DA reaction at a suitable temperature is verified by differential scanning calorimetry and in situ variable temperature solid-state NMR experiments during the cyclic heating and cooling processes. The thermal recyclability and remending ability of the bulk polyurethanes is demonstrated by three polymer processing methods, including hot-press molding, injection molding, and solution casting. It is notable that all the recycled cross-linked polymers display nearly invariable elongation/stress at break compared to the as-synthesized samples. Further end-group functionalization of this single molecular DA crosslinker provides the potential in preparing a wide range of recyclable cross-linked polymers. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
13. [Erythromycin in therapy of cyclic vomiting syndrome]. PubMed Pavlović, Momcilo; Radlović, Nedeljko; Leković, Zoran; Berenji, Karolina 2007-01-01 Cyclic vomiting syndrome is an insufficiently understood disorder which manifests itself in stereotypical episodes of vomiting with no detectable organic cause. Considering its unknown aetiology, drugs borrowed from various medication classes are applied in the therapy of this disorder, with variable success. Among other medicaments, erythromycin is also used in treatment of cyclic vomiting syndrome. This is a case study in which the application of erythromycin led to the prevention of attacks of cyclic vomiting syndrome. Our case report presents how periodical erythromycin therapy in two-week intervals at expected attack periods in a girl led to disappearance of cyclic vomiting. Adverse effects of erythromycin did not show up.
14. [Cyclic Cushing's Syndrome - rare or rarely recognized]. PubMed Kiałka, Marta; Doroszewska, Katarzyna; Mrozińska, Sandra; Milewicz, Tomasz; Stochmal, Ewa 2015-01-01 Cyclic Cushing's syndrome is a type of Cushing's disease which is characterized by alternating periods of increasing and decreasing levels of cortisol in the blood. The diagnostic criteria for cyclic Cushing's syndrome are at least three periods of hypercortisolism alternating with at least two episodes of normal levels of serum cortisol concentration. The epidemiology, signs, symptoms, pathogenesis and treatment of cyclic Cushing's syndrome have been discussed.
15. Redox-Controlled Olefin [Co]Polymerization Catalyzed by Ferrocene-Bridged Phosphine-Sulfonate Palladium Complexes. PubMed Chen, Min; Yang, Bangpei; Chen, Changle 2015-12-14 The facile and reversible interconversion between neutral and oxidized forms of palladium complexes containing ferrocene-bridged phosphine sulfonate ligands was demonstrated. The activity of these palladium complexes could be controlled using redox reagents during ethylene homopolymerization, ethylene/methyl acrylate copolymerization, and norbornene oligomerization. Specifically in norbornene oligomerization, the neutral complexes were not active at all whereas the oxidized counterparts showed appreciable activity. In situ switching between the neutral and oxidized forms resulted in an interesting "off" and "on" behavior in norbornene oligomerization. This work provides a new strategy to control the olefin polymerization process. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
16. Conversion of 2,3-butanediol to 2-butanol, olefins and fuels DOEpatents Lilga, Michael A.; Lee, Guo-Shuh; Lee, Suh-Jane 2016-12-13 Embodiments of an integrated method for step-wise conversion of 2,3-butanediol to 2-butanol, and optionally to hydrocarbons, are disclosed. The method includes providing an acidic catalyst, exposing a composition comprising aqueous 2,3-butanediol to the acidic catalyst to produce an intermediate composition comprising methyl ethyl ketone, providing a hydrogenation catalyst that is spatially separated from the acidic catalyst, and subsequently exposing the intermediate composition to the hydrogenation catalyst to produce a composition comprising 2-butanol. The method may further include subsequently exposing the composition comprising 2-butanol to a deoxygenation catalyst, and deoxygenating the 2-butanol to form hydrocarbons. In some embodiments, the hydrocarbons comprise olefins, such as butenes, and the method may further include subsequently exposing the hydrocarbons to a hydrogenation catalyst to form saturated hydrocarbons.
17. Incorporation of Amino Acids with Long-Chain Terminal Olefins into Proteins. PubMed Exner, Matthias P; Köhling, Sebastian; Rivollier, Julie; Gosling, Sandrine; Srivastava, Puneet; Palyancheva, Zheni I; Herdewijn, Piet; Heck, Marie-Pierre; Rademann, Jörg; Budisa, Nediljko 2016-02-29 The increasing need for site-specific protein decorations that mimic natural posttranslational modifications requires access to a variety of noncanonical amino acids with moieties enabling bioorthogonal conjugation chemistry. Here we present the incorporation of long-chain olefinic amino acids into model proteins with rational variants of pyrrolysyl-tRNA synthetase [PylRS]. Nε-heptenoyl lysine was incorporated for the first time using the known promiscuous variant PylRS[Y306A/Y384F], and Nε-pentenoyl lysine was incorporated in significant yields with the novel variant PylRS[C348A/Y384F]. This is the only example of rational modification at position C348 to enlarge the enzyme's binding pocket. Furthermore, we demonstrate the feasibility of our chosen amino acids in the thiol-ene conjugation reaction with a thiolated polysaccharide.
18. The role of peel stresses in cyclic debonding NASA Technical Reports Server [NTRS] Everett, R. A., Jr. 1982-01-01 When an adhesively bonded joint is undergoing cyclic loading, one of the possible damage modes that occurs is called cyclic debonding - progressive separation of the adherends by failure of the adhesive bond under cyclic loading. In most practical structures, both peel and shear stresses exist in the adhesive bonding during cyclic loading. The results of an experimental and analytical study to determine the role of peel stresses on cyclic debonding in a mixed mode specimen are presented. Experimentally, this was done by controlling the forces that create the peel stresses by applying a clamping force to oppose the peel stresses. Cracked lap shear joints were chosen for this study. A finite element analysis was developed to assess the effect of the clamping force on the strain energy release rates due to shear and peel stresses. The results imply that the peel stress is the principal stress causing cyclic debonding.
19. Pyrrolidine and Piperidine Formation Via Copper[II] Carboxylate Promoted Intramolecular Carboamination of Unactivated Olefins: Diastereoselectivity and Mechanism PubMed Central Sherman, Eric S.; Fuller, Peter H.; Kasi, Dhanalakshmi; Chemler, Sherry R. 2008-01-01 An expanded substrate scope and in depth analysis of the reaction mechanism of the copper[II] carboxylate promoted intramolecular carboamination of unactivated alkenes is described. This method provides access to N-functionalized pyrrolidines and piperidines. Both aromatic and aliphatic γ- and δ-alkenyl N-arylsulfonamides undergo the oxidative cyclization reaction efficiently. N-Benzoyl-2-allylaniline also underwent the oxidative cyclization. The terminal olefin substrates examined were more reactive than those with internal olefins, and the latter terminated in elimination rather than carbon-carbon bond formation. The efficiency of the reaction was enhanced by the use of more organic soluble copper[II] carboxylate salts, copper[II] neodecanoate in particular. The reaction times were reduced by the use of microwave heating. High levels of diastereoselectivity were observed in the synthesis of 2,5-disubstituted pyrrolidines, wherein the cis substitution pattern predominates. The mechanism of the reaction is discussed in the context of the observed reactivity and in comparison to analogous reactions promoted by other reagents and conditions. Our evidence supports a mechanism wherein the N-C bond is formed via intramolecular syn aminocupration and the C-C bond is formed via intramolecular addition of a primary carbon radical to an aromatic ring. PMID:17428100
20. Triphenylphosphine-based functional porous polymer as an efficient heterogeneous catalyst for the synthesis of cyclic carbonates from CO2 NASA Astrophysics Data System [ADS] Wu, Siduo; Teng, Chao; Cai, Sheng; Jiang, Biwang; Wang, Yong; Meng, Hong; Tao, Huchun 2017-11-01 A novel triphenylphosphine-based porous polymer [TPDB] with a high Brunauer-Emmett-Teller [BET] surface area was synthesized through Friedel-Crafts alkylation of triphenylphosphine and α-dibromo- p-xylene. Then, the functional hydroxyl groups were successfully grafted onto the polymer framework by post modification of TPDB with 3-bromo-1-propanol [BP] and triethanolamine [TEA]. The resulting sample TPDB-BP-TEA was characterized by various techniques such as FT-IR, TG, SEM, EDS mapping, ICP-MS, and N2 adsorption-desorption. This new polymer was tested as the catalyst in the solvent-free cycloaddition reaction of CO2 with epoxides, which exhibited excellent performance, with high yield, selectivity, and stable recyclability for several catalytic cycles. The comparison experiment results demonstrate that the bromide ions and hydroxyl groups, as well as high surface area, are key factors in improving the catalytic activity of this new catalyst.

1. Wiring microbial biofilms to the electrode by osmium redox polymer for the performance enhancement of microbial fuel cells. PubMed Yuan, Yong; Shin, Hyosul; Kang, Chan; Kim, Sunghyun 2016-04-01 An osmium redox polymer, PAA-PVI-[Os[4,4'-dimethyl-2,2'-bipyridine]2Cl]+/2+ that has been used in enzymatic fuel cells and microbial sensors, was applied for the first time to the anode of single-chamber microbial fuel cells with the mixed culture inoculum aiming at enhancing performance. Functioning as a molecular wire connecting the biofilm to the anode, power density increased from 1479 mW m[-2] without modification to 2355 mW m[-2] after modification of the anode. Evidence from cyclic voltammetry showed that the catalytic activity of an anodic biofilm was greatly enhanced in the presence of an osmium redox polymer, indicating that electrons were more efficiently transferred to the anode via co-immobilized osmium complex tethered to wiring polymer chains at the potential range of -0.3 V-+0.1 V [vs. SCE]. The optimum amount of the redox polymer was determined to be 0.163 mg cm[-2]. Copyright © 2015 Elsevier B.V. All rights reserved.
2. Effects of Residual Solvent Molecules Facilitating the Infiltration Synthesis of ZnO in a Nonreactive Polymer DOE Office of Scientific and Technical Information [OSTI.GOV] Ye, Xinyi; Kestell, John; Kisslinger, Kim Infiltration synthesis, the atomic-layer-deposition-based organic–inorganic material hybridization technique that enables unique hybrid composites with improved material properties and inorganic nanostructures replicated from polymer templates, is shown to be driven by the binding reaction between reactive chemical groups of polymers and perfusing vapor-phase material precursors. Here in this paper, we discover that residual solvent molecules from polymer processing can react with infiltrating material precursors to enable the infiltration synthesis of metal oxides in a nonreactive polymer. The systematic study, which combines in situ quartz crystal microgravimetry, polarization-modulated infrared reflection–absorption spectroscopy, X-ray photoelectron spectroscopy, and transmission electron microscopy, shows that the ZnOmore » infiltration synthesis in nominally nonreactive SU-8 polymer is mediated by residual processing solvent cyclopentanone, a cyclic ketone whose Lewis-basic terminal carbonyl group can react with the infiltrating Lewis-acidic Zn precursor diethylzinc [DEZ]. In addition, we find favorable roles of residual epoxy rings in the SU-8 film in further assisting the infiltration synthesis of ZnO. Lastly, the discovered rationale not only improves the understanding of infiltration synthesis mechanism, but also potentially expands its application to more diverse polymer systems for the generation of unique functional organic–inorganic hybrids and inorganic nanostructures.« less
3. Effects of Residual Solvent Molecules Facilitating the Infiltration Synthesis of ZnO in a Nonreactive Polymer DOE PAGES Ye, Xinyi; Kestell, John; Kisslinger, Kim; ... 2017-05-04 Infiltration synthesis, the atomic-layer-deposition-based organic–inorganic material hybridization technique that enables unique hybrid composites with improved material properties and inorganic nanostructures replicated from polymer templates, is shown to be driven by the binding reaction between reactive chemical groups of polymers and perfusing vapor-phase material precursors. Here in this paper, we discover that residual solvent molecules from polymer processing can react with infiltrating material precursors to enable the infiltration synthesis of metal oxides in a nonreactive polymer. The systematic study, which combines in situ quartz crystal microgravimetry, polarization-modulated infrared reflection–absorption spectroscopy, X-ray photoelectron spectroscopy, and transmission electron microscopy, shows that the ZnOmore » infiltration synthesis in nominally nonreactive SU-8 polymer is mediated by residual processing solvent cyclopentanone, a cyclic ketone whose Lewis-basic terminal carbonyl group can react with the infiltrating Lewis-acidic Zn precursor diethylzinc [DEZ]. In addition, we find favorable roles of residual epoxy rings in the SU-8 film in further assisting the infiltration synthesis of ZnO. Lastly, the discovered rationale not only improves the understanding of infiltration synthesis mechanism, but also potentially expands its application to more diverse polymer systems for the generation of unique functional organic–inorganic hybrids and inorganic nanostructures.« less
4. Kinetic Studies of the Thermal Decomposition of Methylperoxynitrate and of Ozone-Olefin Reactions. NASA Astrophysics Data System [ADS] Bahta, Abraha This research concerns the thermal decomposition kinetics of CH[,3]O[,2]NO[,2] and laboratory kinetic measurements of ozone-olefin reactions. In the first system, the thermal decomposition rate of CH[,3]O[,2]NO[,2] was studied in the temperature range of 256-268 K at [TURN]350 torr total pressure and in the pressure range of 50-720 torr at 263 K by the perturbation of the equilibrium: [UNFORMATTED TABLE FOLLOWS]. CH[,3]O[,2] + NO[,2] [+M] [DBLARR] CH[,3]O[,2]NO[,2] [+M] [3,-3]. with NO. CH[,3]O[,2] + NO [--->] CH[,3]O + NO[,2] [4]. [TABLE ENDS]. The CH[,3]O[,2]NO[,2] was generated in situ by the photolysis of Cl[,2] in the presence of O[,2], CH[,4] and NO[,2]. The decomposition kinetics were monitored in the presence of NO by the change in ultraviolet absorption at 250 nm. The Arrhenius expression obtained for the thermal decomposition is k[,-3] = 6 x 10['15] exp{-[21,000 [+OR-] 1500]/RT} sec['-1] at [TURNEQ]350 torr total pressure [mostly CH[,4]] where R = 1.987 cal/mole['-] K. The uncertainty in the Arrhenius parameters can be greatly reduced by combining this expression with data for k[,3] and thermodynamics data to give k[,-3] = [6 [+OR-] 3] x 10['15] exp{-[21,300 [+OR-] 300]/RT} sec['-1] at [TURNEQ]350 torr total pressure. Computations based on the pressure dependence of the forward reaction give k[,-3]['[INFIN]] = 2.1 x 10['16] exp{-[21,700 [+OR -] 300]/RT} sec['-1] k[,-3]['[DEGREES]] = 3.3 x 10[' -4] exp{-[20,150 x 300]/RT} cm['3] sec['-1]. At 263 K the equilibrium constant K[,3,-3]{263 K} is determined to be [2.68 [+OR-] 0.26] x 10['-10] cm['3]. In the stratosphere the CH[,3]O[,2]NO[,2] lifetime will be controlled by play a role in the NO[,x] budget of the lower stratosphere. In the second part, the kinetics of the reactions of O[,3] with C[,2]H[,4], C[,3]H[,4], 1,3-C[,4]H[,6], and trans-1,3-C[,5]H[,8] were studied with initial olefin-to -ozone ratios [GREATERTHEQ] 4.9, in the presence of excess O[,2], and over the temperature range 232 to 300 K. The
5. Silicone-containing aqueous polymer dispersions with hybrid particle structure. PubMed Kozakiewicz, Janusz; Ofat, Izabela; Trzaskowska, Joanna 2015-09-01 In this paper the synthesis, characterization and application of silicone-containing aqueous polymer dispersions [APD] with hybrid particle structure are reviewed based on available literature data. Advantages of synthesis of dispersions with hybrid particle structure over blending of individual dispersions are pointed out. Three main processes leading to silicone-containing hybrid APD are identified and described in detail: [1] emulsion polymerization of organic unsaturated monomers in aqueous dispersions of silicone polymers or copolymers, [2] emulsion copolymerization of unsaturated organic monomers with alkoxysilanes or polysiloxanes with unsaturated functionality and [3] emulsion polymerization of alkoxysilanes [in particular with unsaturated functionality] and/or cyclic siloxanes in organic polymer dispersions. The effect of various factors on the properties of such hybrid APD and films as well as on hybrid particles composition and morphology is presented. It is shown that core-shell morphology where silicones constitute either the core or the shell is predominant in hybrid particles. Main applications of silicone-containing hybrid APD and related hybrid particles are reviewed including [1] coatings which show specific surface properties such as enhanced water repellency or antisoiling or antigraffiti properties due to migration of silicone to the surface, and [2] impact modifiers for thermoplastics and thermosets. Other processes in which silicone-containing particles with hybrid structure can be obtained [miniemulsion polymerization, polymerization in non-aqueous media, hybridization of organic polymer and polysiloxane, emulsion polymerization of silicone monomers in silicone polymer dispersions and physical methods] are also discussed. Prospects for further developments in the area of silicone-containing hybrid APD and related hybrid particles are presented. Copyright © 2015. Published by Elsevier B.V.
6. High liquid yield process for retorting various organic materials including oil shale DOEpatents Coburn, Thomas T. 1990-01-01 This invention is a continuous retorting process for various high molecular weight organic materials, including oil shale, that yields an enhanced output of liquid product. The organic material, mineral matter, and an acidic catalyst, that appreciably adsorbs alkenes on surface sites at prescribed temperatures, are mixed and introduced into a pyrolyzer. A circulating stream of olefin enriched pyrolysis gas is continuously swept through the organic material and catalyst, whereupon, as the result of pyrolysis, the enhanced liquid product output is provided. Mixed spent organic material, mineral matter, and cool catalyst are continuously withdrawn from the pyrolyzer. Combustion of the spent organic material and mineral matter serves to reheat the catalyst. Olefin depleted pyrolysis gas, from the pyrolyzer, is enriched in olefins and recycled into the pyrolyzer. The reheated acidic catalyst is separated from the mineral matter and again mixed with fresh organic material, to maintain the continuously cyclic process.
7. A high liquid yield process for retorting various organic materials including oil shale DOEpatents Coburn, T.T. 1988-07-26 This invention is a continuous retorting process for various high molecular weight organic materials, including oil shale, that yields an enhanced output of liquid product. The organic material, mineral matter, and an acidic catalyst, that appreciably adsorbs alkenes on surface sites at prescribed temperatures, are mixed and introduced into a pyrolyzer. A circulating stream of olefin enriched pyrolysis gas is continuously swept through the organic material and catalyst, whereupon, as the result of pyrolysis, the enhanced liquid product output is provided. Mixed spent organic material, mineral matter, and cool catalyst are continuously withdrawn from the pyrolyzer. Combustion of the spent organic material and mineral matter serves to reheat the catalyst. Olefin depleted pyrolysis gas, from the pyrolyzer, is enriched in olefins and recycled into the pyrolyzer. The reheated acidic catalyst is separated from the mineral matter and again mixed with fresh organic material, to maintain the continuously cyclic process. 2 figs.
8. Determination of mineral oil aromatic hydrocarbons in edible oils and fats by online liquid chromatography-gas chromatography-flame ionization detection - Evaluation of automated removal strategies for biogenic olefins. PubMed Nestola, Marco; Schmidt, Torsten C 2017-07-07 The determination of mineral oil aromatic hydrocarbons [MOAH] in foodstuffs gained in importance over the last years as carcinogenicity cannot be excluded for certain MOAH. The existence of olefins in foodstuffs, such as edible oils and fats, can be problematic for the determination of MOAH by LC-GC-FID. Removal of these interfering substances by HPLC based on polarity differences is not possible. During gas chromatographic separation heavily overloaded peaks are observed rendering the detection of small mineral oil contaminations almost impossible. Therefore, removal of these olefins is necessary before subjection of the sample to LC-GC-FID. Epoxidation of olefins to increase their polarity proved to be a valuable tool in the past. Precision and trueness of the results as shown in a collaborative trial, however, are relying on exact reaction conditions. Additionally, it is known that certain MOAH are oxidized during epoxidation and therefore get lost. In the scope of this work, hydroboration, bromohydrin reaction, and epoxidation were examined for their potential for derivatization of unsaturated hydrocarbons with increased robustness and higher recovery of MOAH. Epoxidation by meta-chloroperoxybenzoic acid [mCPBA] delivered the best removal of olefins. Factors influencing this reaction were enlightened. Adaption of the reaction conditions and time-controlled automation increased the recovery of polycyclic MOAH. Good precision [RSD r