The Experts below are selected from a list of 133515 Experts worldwide ranked by ideXlab platform
Jaroslav Mosnacek - One of the best experts on this subject based on the ideXlab platform.
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synthesis morphology and mechanical properties of linear triblock copolymers based on poly alpha methylene gamma butyrolactone
Polymer, 2009Co-Authors: Jaroslav Mosnacek, Jeong Ae Yoon, Azhar Juhari, Kaloian Koynov, Krzysztof MatyjaszewskiAbstract:A series of well-defined triblock copolymers containing middle soft poly(n-butyl acrylate) (PBA) block and outer hard blocks of poly(α-methylene-γ-butyrolactone) homopolymer (PMBL) or random poly (α-methylene-γ-butyrolactone)-r-poly(methyl methacrylate) copolymer (PMBL-r-PMMA) were synthesized by atom transfer radical polymerization (ATRP). Phase separated morphologies of cylindrical or spherical hard block domains arranged in the soft PBA matrix were observed by atomic force microscopy and small-angle X-ray scattering. The mechanical and thermal properties of the copolymers were thoroughly characterized and their thermoplastic elastomer behavior was studied. Dynamic mechanical analysis (DMA) showed for all PMBL-b-PBA-b-PMBL copolymers a very broad rubbery plateau range extending up to temperatures of 300 °C. Replacement of the PMBL hard block with the less brittle PMBL-r-PMMA resulted in an improvement of the tensile properties, without compromising the very good thermal stability of the materials.
Krzysztof Matyjaszewski - One of the best experts on this subject based on the ideXlab platform.
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synthesis morphology and mechanical properties of linear triblock copolymers based on poly alpha methylene gamma butyrolactone
Polymer, 2009Co-Authors: Jaroslav Mosnacek, Jeong Ae Yoon, Azhar Juhari, Kaloian Koynov, Krzysztof MatyjaszewskiAbstract:A series of well-defined triblock copolymers containing middle soft poly(n-butyl acrylate) (PBA) block and outer hard blocks of poly(α-methylene-γ-butyrolactone) homopolymer (PMBL) or random poly (α-methylene-γ-butyrolactone)-r-poly(methyl methacrylate) copolymer (PMBL-r-PMMA) were synthesized by atom transfer radical polymerization (ATRP). Phase separated morphologies of cylindrical or spherical hard block domains arranged in the soft PBA matrix were observed by atomic force microscopy and small-angle X-ray scattering. The mechanical and thermal properties of the copolymers were thoroughly characterized and their thermoplastic elastomer behavior was studied. Dynamic mechanical analysis (DMA) showed for all PMBL-b-PBA-b-PMBL copolymers a very broad rubbery plateau range extending up to temperatures of 300 °C. Replacement of the PMBL hard block with the less brittle PMBL-r-PMMA resulted in an improvement of the tensile properties, without compromising the very good thermal stability of the materials.
Jean-pierre Lepoittevin - One of the best experts on this subject based on the ideXlab platform.
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chronic actinic dermatitis to sesquiterpene lactones 2 2 photoreaction toward thymidine of and α methylene hexahydrobenzofuranone with a cis ring junction
Photochemistry and Photobiology, 2010Co-Authors: Sébastien Fuchs, Valérie Berl, Jean-pierre LepoittevinAbstract:(+) and (-) Alpha-Methylene-hexahydrobenzofuranone derivatives with a stereochemically pure cis ring junction were used as models of sesquiterpene lactones to study their photoreactivity toward thymidine. After 313 nm irradiation of a deoxygenated acetone solution of lactone models and thymidine, six [2+2] photoadducts were isolated for each enantiomer and fully characterized by a combination of NMR experiments. A common syn regioselectivity and exo stereoselectivity were observed for photoadducts. This high photoreactivity of Alpha-Methylene-Gamma-Butyrolactone ring toward thymidine could be an explanation of the progressive evolution of allergic contact dermatitis toward chronic actinic dermatitis.
Jeong Ae Yoon - One of the best experts on this subject based on the ideXlab platform.
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synthesis morphology and mechanical properties of linear triblock copolymers based on poly alpha methylene gamma butyrolactone
Polymer, 2009Co-Authors: Jaroslav Mosnacek, Jeong Ae Yoon, Azhar Juhari, Kaloian Koynov, Krzysztof MatyjaszewskiAbstract:A series of well-defined triblock copolymers containing middle soft poly(n-butyl acrylate) (PBA) block and outer hard blocks of poly(α-methylene-γ-butyrolactone) homopolymer (PMBL) or random poly (α-methylene-γ-butyrolactone)-r-poly(methyl methacrylate) copolymer (PMBL-r-PMMA) were synthesized by atom transfer radical polymerization (ATRP). Phase separated morphologies of cylindrical or spherical hard block domains arranged in the soft PBA matrix were observed by atomic force microscopy and small-angle X-ray scattering. The mechanical and thermal properties of the copolymers were thoroughly characterized and their thermoplastic elastomer behavior was studied. Dynamic mechanical analysis (DMA) showed for all PMBL-b-PBA-b-PMBL copolymers a very broad rubbery plateau range extending up to temperatures of 300 °C. Replacement of the PMBL hard block with the less brittle PMBL-r-PMMA resulted in an improvement of the tensile properties, without compromising the very good thermal stability of the materials.
Kaloian Koynov - One of the best experts on this subject based on the ideXlab platform.
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synthesis morphology and mechanical properties of linear triblock copolymers based on poly alpha methylene gamma butyrolactone
Polymer, 2009Co-Authors: Jaroslav Mosnacek, Jeong Ae Yoon, Azhar Juhari, Kaloian Koynov, Krzysztof MatyjaszewskiAbstract:A series of well-defined triblock copolymers containing middle soft poly(n-butyl acrylate) (PBA) block and outer hard blocks of poly(α-methylene-γ-butyrolactone) homopolymer (PMBL) or random poly (α-methylene-γ-butyrolactone)-r-poly(methyl methacrylate) copolymer (PMBL-r-PMMA) were synthesized by atom transfer radical polymerization (ATRP). Phase separated morphologies of cylindrical or spherical hard block domains arranged in the soft PBA matrix were observed by atomic force microscopy and small-angle X-ray scattering. The mechanical and thermal properties of the copolymers were thoroughly characterized and their thermoplastic elastomer behavior was studied. Dynamic mechanical analysis (DMA) showed for all PMBL-b-PBA-b-PMBL copolymers a very broad rubbery plateau range extending up to temperatures of 300 °C. Replacement of the PMBL hard block with the less brittle PMBL-r-PMMA resulted in an improvement of the tensile properties, without compromising the very good thermal stability of the materials.