The Experts below are selected from a list of 41544 Experts worldwide ranked by ideXlab platform
Hynek Balcar - One of the best experts on this subject based on the ideXlab platform.
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SBA-15 Immobilized Ruthenium Carbenes as Catalysts for Ring Closing Metathesis and Ring Opening Metathesis Polymerization
Topics in Catalysis, 2010Co-Authors: David Bek, Naděžda Žilková, Jiří Dědeček, Jan Sedláček, Hynek BalcarAbstract:New hybrid catalysts for olefin metathesis were prepared by immobilization of Hoveyda–Grubbs type Ru alkylidenes on a siliceous SBA-15 support via exchange of chloro ligands for substituted carboxylates. Catalysts proved a high activity in ring closing metathesis of 1,7-octadiene and diethyl diallylmalonate, reusability and low Ru leaching. In Ring Opening Metathesis Polymerization of norbornene and cyclooctene, SBA-15 supported catalyst gave higher yields of high-Molecular-Weight Polymers than corresponding catalyst with conventional silica support.
Peter H Seeberger - One of the best experts on this subject based on the ideXlab platform.
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snowballing radical generation leads to ultrahigh Molecular Weight Polymers
Macromolecular Rapid Communications, 2012Co-Authors: Paola Laurino, Hugo F Hernandez, Judith Brauer, Kathleen Kruger, Hansjorg Grutzmacher, Klaus Tauer, Peter H SeebergerAbstract:Styrene is the classical monomer obeying zero-one kinetics in radical emulsion polymerization. Accordingly, particles that are less than 100 nm in diameter contain either one or no growing radical(s). We describe a unique photoinitiated polymerization reaction accelerated by snowballing radical generation in a continuous flow reactor. Even in comparison to classical emulsion polymerization, these unprecedented snowballing reactions are rapid and high-yielding, with each particle simultaneously containing more than one growing radical. This is a consequence of photoinitiator incorporation into the nascent polymer backbone and repeated radical generation upon photo-irradiation.
David Bek - One of the best experts on this subject based on the ideXlab platform.
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SBA-15 Immobilized Ruthenium Carbenes as Catalysts for Ring Closing Metathesis and Ring Opening Metathesis Polymerization
Topics in Catalysis, 2010Co-Authors: David Bek, Naděžda Žilková, Jiří Dědeček, Jan Sedláček, Hynek BalcarAbstract:New hybrid catalysts for olefin metathesis were prepared by immobilization of Hoveyda–Grubbs type Ru alkylidenes on a siliceous SBA-15 support via exchange of chloro ligands for substituted carboxylates. Catalysts proved a high activity in ring closing metathesis of 1,7-octadiene and diethyl diallylmalonate, reusability and low Ru leaching. In Ring Opening Metathesis Polymerization of norbornene and cyclooctene, SBA-15 supported catalyst gave higher yields of high-Molecular-Weight Polymers than corresponding catalyst with conventional silica support.
Takeshi Fukuda - One of the best experts on this subject based on the ideXlab platform.
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high pressure atom transfer radical polymerization of methyl methacrylate for well defined ultrahigh Molecular Weight Polymers
Polymer, 2008Co-Authors: Toshihiko Arita, Yuzo Kayama, Kohji Ohno, Yoshinobu Tsujii, Takeshi FukudaAbstract:Abstract The feasibility of high-pressure atom transfer radical polymerization (ATRP) for synthesizing well-defined Polymers of extraordinarily high Molecular Weights was demonstrated. ATRP of methyl methacrylate (MMA) under pressures up to 500 MPa was investigated at 60 °C. The addition of a small amount of a Cu(II)Cl 2 /ligand complex along with the general benefits of high pressure of enhancing propagation and suppressing termination brought about an excellent control of polymerization even with an extremely low concentration of ATRP initiator. For example, there was produced PMMA with a number-average Molecular Weight M n of 3.6 × 10 6 and a polydispersity index of 1.24, which had never been achieved by conventional ATRP.
Paola Laurino - One of the best experts on this subject based on the ideXlab platform.
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snowballing radical generation leads to ultrahigh Molecular Weight Polymers
Macromolecular Rapid Communications, 2012Co-Authors: Paola Laurino, Hugo F Hernandez, Judith Brauer, Kathleen Kruger, Hansjorg Grutzmacher, Klaus Tauer, Peter H SeebergerAbstract:Styrene is the classical monomer obeying zero-one kinetics in radical emulsion polymerization. Accordingly, particles that are less than 100 nm in diameter contain either one or no growing radical(s). We describe a unique photoinitiated polymerization reaction accelerated by snowballing radical generation in a continuous flow reactor. Even in comparison to classical emulsion polymerization, these unprecedented snowballing reactions are rapid and high-yielding, with each particle simultaneously containing more than one growing radical. This is a consequence of photoinitiator incorporation into the nascent polymer backbone and repeated radical generation upon photo-irradiation.