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Showing 1 to 20 of 51 for “"Random copolymers"”.
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Morphology, Crystallization and Melting Behaviors of Random Copolymers of Ethylene with 1-Butene, 1-Pentene and 1-Hexene
… behaviors of a series of ethylene/alpha-olefin copolymers were investigated as a function of comonomer content, comonomer type and processing conditions, including crystallization temperature and time. This was achieved by using a combination of techniques such as Nuclear Magnetic Resonance …
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Synthesis and Characterization of Disulfonated Poly(Arylene Ether Sulfone) Random Copolymers as Multipurpose Membranes for Reverse Osmosis and Fuel Cell Applications
… of several disulfonated poly(arylene ether) random copolymer membranes in fuel cell and reverse osmosis applications. Poly(arylene ether)s were prepared by direct step copolymerization using a third monomer 3,3–-disulfonated 4,4–-dichlorodiphenylsulfone. The membrane properties of a …
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Direct Polymerization Of Sulfonated Poly(arylene ether) Random Copolymers And Poly(imide)Sulfonated Poly(arylene ether) Segmented Copolymers: New Candidates For Proton Exchange Membrane Fuel Cell Material Systems
… weight, film-forming, ductile, ion conducting copolymers. These were converted to the acid form and investigated as proton exchange membranes for fuel cells. Hydrophilicity increased with the level of sulfonation. However, water sorption increased gradually until about 50 mole percent SDCDPS …
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Structure Property Relationships of Proton Exchange Membranes
… properties. Most of the hydrocarbon based random copolymers reported in the literature show reduced proton conductivity at low water content. This was attributed to the formation of an isolated morphology. Over the last few years our group has synthesized thermally stable multiblock …
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Molecular and Polymeric Materials Based On Asymmetrically Substituted BF2 3-Cyanoformazanates
… This reaction was used to make homo, block, and random copolymers, where the comonomer was an organic norbornene derivative. Spectroscopic studies of these polymers revealed that, as the mole fraction of BF2 (ƒBF2) in random copolymers decreased, the quantum yield of fluorescence increased; this …
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Bio-inspired Design and Self-Assembly of Nucleobase- and Ion-Containing Polymers
… afforded acrylic ABC and ABA triblock copolymers with nucleobase-functionalized external blocks and a low-Tg central block. The hard-soft-hard triblock polymer architecture drove microphase-separation into a physically crosslinked hard phase in a low Tg matrix. Hydrogen bonding in the …
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Synthesis and characterization of thermo-responsive polyethers
… thermo-responsive properties. Thermo-responsive random copolymers of glycidyl methyl ether (GME) and epoxyhexane (EH) were synthesized. Once their properties were studied, they were grafted onto hyaluronic acid to obtain gelation at temperatures above the phase transition temperature of poly …
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Synthesis and Characterization of Cation-Containing and Hydrogen Bonding Supramolecular Polymers
… ionic aggregation were studied in block and random polymers synthesized using controlled radical polymerization techniques such as nitroxide mediated polymerization (NMP) and reversible addition-fragmentation chain transfer polymerization (RAFT). Non-covalent interactions were expected to …
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Structure and Properties of Nano- and Meso-scale Materials Prepared by Designed Self-Aasembly of Nanoparticles
… of gold nanorods with different dimensions into random and block copolymer structures (plasmonic copolymers). The approach was extended to the co-assembly of random copolymers of gold and palladium nanorods. We showed that the formation of random copolymers is achieved regardless of the …
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Thermodynamic Interactions in Polydiene/Polyolefin Blends
… ethylene) (PEE), polyethylene (PE), PE-co-PEE random copolymers, and poly(ethylene-alt-propylene) (PEP). Additionally, a model atactic polypropylene (aPP) prepared using a metallocene catalyst was used in this study. SANS data were interpreted using Zimm analysis and the Random Phase …
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Synthesis and characterization of poly (butyl vinyl ether) homopolymers and copolymers utilizing the aluminum hydrogen sulfate catalyst system
… (butyl vinyl ether 2-chloroethyl vinyl ether) random copolymers was accomplished through the use of the aluminum hydrogen sulfate catalyst (AHS). In this system, AHS acts as a heterogeneous catalyst in the cationic polymerization of vinyl alkyl ethers. Highly isotactic polymers (greater than …
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Development of and gas permeation study of homo and copolymers from the family of polyphenylene oxides
… on preparation and characterization of new copolymers from the family of polyphenylene oxides. This family of polymers was chosen because of the properties of its best-known representative, poly(2,6-dimethyl-1,4-phenylene oxide), which shows one of the highest rates of permeability for gases …
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Studies and Optimization of All-Polymer Solar Cells based on Naphthalene Diimide-Biselenophene Copolymer Acceptors
… In addition, all-PCSs based on donor PBDB-T and random copolymer acceptors, BSSx (x=10, 20, and 50), were found to have improved morphology, due to the fine tuned bulk crystallinity of the random copolymers. Finally, we explored solution-processed electron transport layers (ETLs) as a way to …
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Prediction of Linear Viscoelastic Response of the Loss Shear Modulus of Polymer-Modified Binders
… modeling of loss shear modulus of polymer (random copolymers and thermoplastic block copolymers) modified binder. Data from dynamic mechanical analysis on modified binders, at temperatures between 5 and 75°C and frequencies ranging from 0.06 to 0188.5 rad/s, were reduced to dynamic master …
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Responsive polymers for dynamic modulation of bio-macromolecular transport properties
… to device design and automation. Amphiphilic copolymers with azobenzene moieties are of interest because the azobenzene can undergo reversible trans-cis photoisomerization leading to conformational isomers with significantly dissimilar dipole moments and hydrophobicities and thus different …
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Thermoresponsive Glycopolymers via Controlled Radical Polymerization (RAFT) for Biomolecular Recognition
… at ~ 32° C in aqueous solution. Additionally, glycopolymers, where free sugar units are present, have potentially interesting applications especially in bio-recognition where sugars play an important role. In this work, our interest was focused on the synthesis of glycomonomers and its block- and …
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Proton Exchange Membrane Fuel Cell Systems Based on Aromatic Hydrocarbon and Partially Fluorinated Disulfonated Poly(Arylene Ether) Copolymers
… nitrile containing poly (arylene ether sulfone) random copolymers was demonstrated. Various levels of disulfonation allowed the membrane characteristics to be investigated as a function of the membrane ion exchange capacity. The results favorably compare with the current state-of-the-art …
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Gas transport properties of poly(n-alkyl acrylate) blends and modeling of modified atmosphere storage using selective and non-selective membranes
… acrylate) blended with n-aliphatic materials and random copolymers of poly(n-alkyl acrylates) are briefly examined. A bulk modified atmospheric storage design is proposed where produce is stored in a rigid chamber that is equipped with both selective and non-selective membrane modules that help …
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The ring opening polymerization of ring strained cyclic ethers
… rOXT = 1.2 ± 0.30 and rTHF = 0.14 ± 0.03. These copolymers were random copolymers with no evidence of oligomer formation. The coordinated anionic catalyst, porphinato-aluminium chloride [(TPP)AICl], was used to produce a living polymerization of oxetane. An overall third-order kinetics was …
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Modeling of the linear viscoelastic response of polymer modified asphalt binders at intermediate and high temperatures
… The modifiers, representing a wide variety of random copolymers and thermoplastic block copolymers, were blended with asphalt at three concentration levels to yield a total of twenty one mixes. The effect of short term aging was simulated by the rolling thin film oven test (RTFOT) procedure. A …
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