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Methacrylate Polymerization (methacrylate + polymerization)
Kinds of Methacrylate Polymerization Selected AbstractsStereospecific polymerization of methacrylates by metallocene and related catalystsJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 14 2004Eugene Y.-X. Abstract Stereospecific,isospecific, syndiospecific, and diastereospecific,polymerizations of methacrylates using group 4 metallocene and related catalysts produce polymethacrylates with controlled stereo-microstructures. The versatility and stereospecificity of these cat- alysts for methyl methacrylate polymerization were demonstrated not only in solution-phase polymerization, but also in polymerizations on silica surfaces and inside silicate nanogalleries. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 3395,3403, 2004 [source] Synthesis and spectroscopic characterization of symmetrical isoprene,methyl methacrylate diblock copolymers bearing different anthracene derivatives at the junctionsJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 9 2003Jian Yang Abstract We describe the synthesis and characterization of 1-(1-anthryl)-1-phenylethylene (1-An-E) and 1-(2-anthryl)-1-phenylethylene (2-An-E). These species were used to end cap the living end group of polyisoprene (PI) obtained by anionic polymerization in tetrahydrofuran. The anions generated were used to initiate methyl methacrylate polymerization. In this way, we synthesized two symmetrical PI-poly(methyl methacrylate) (PMMA) block copolymers each with a single dye at the junction. PI-An1-PMMA has an anthracene linked via its 1-position. PI-An2-PMMA has the anthracene linked via its 2-position. We compare the UV and fluorescence properties of the polymers to model compounds with similar chromophores. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 1225,1236, 2003 [source] Viscosity effects in cobaloxime-mediated catalytic chain-transfer polymerization of methacrylatesJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 6 2002G. Evan Roberts Abstract The effect of bulk viscosity on the cobaloxime-mediated catalytic chain-transfer polymerization of methacrylates at 60 °C was investigated by both the addition of high molecular weight poly(methyl methacrylate) to methyl methacrylate polymerization and the dilution of benzyl methacrylate polymerization by toluene. The results indicate that the bulk viscosity is not directly linked to the chain-transfer activity. The previously measured relationship between chain-transfer-rate coefficient and monomer viscosity therefore probably reflects changes at the molecular level. However, the results in this article do not necessarily disprove a diffusion-controlled reaction rate because cobaloxime diffusion is expected to scale with the monomer friction coefficient rather than bulk viscosity. Considering the published data, to date we are not able to distinguish between a diffusion-controlled reaction rate or a mechanism directly affected by the methacrylate substituent. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 782,792, 2002; DOI 10.1002/pola.10152 [source] Chain Transfer and Efficiency of End-Group Introduction in Free Radical Polymerization of Methyl Methacrylate in the Presence of Poly(methyl methacrylate) MacromonomerMACROMOLECULAR RAPID COMMUNICATIONS, Issue 22 2004Kazuki Miyake Abstract Summary: Experimental and modeling studies of addition,fragmentation chain transfer (AFCT) during radical polymerization of methyl methacrylate in the presence of poly(methyl methacrylate) macromonomer with 2-carbomethoxy-2-propenyl , -ends (PMMA-CO2Me) at 60,°C are reported. The results revealed that AFCT involving PMMA-CO2Me formed in situ during methyl methacrylate polymerization has a negligible effect on the molecular weight distribution. [source] Free radical polymerization of methyl methacrylate initiated by the diphosphine Mo(0) complexesAPPLIED ORGANOMETALLIC CHEMISTRY, Issue 11 2006Ayfer Mente Abstract The polymerization of methyl methacrylate MMA catalyzed by [Mo(CO)4L2] [L2 = diphenylphosphinomethane (dppm), diphenylphosphinoethane (dppe) or diphenylphosphinopropane (dppp)] has been studied. The activity of these single-component catalysts depends on the length of the (CH2)n bridge of diphosphine ligand. Thus, the dppm derivative displays higher activity than dppe or dppp ligands. These complexes, as free radical initiators, afforded the methyl methacrylate polymerization in chlorinated solvents. The mechanism of the polymerization was discussed and a radical mechanism was proposed. Copyright © 2006 John Wiley & Sons, Ltd. [source] High-Speed Living Polymerization of Polar Vinyl Monomers by Self-Healing Silylium CatalystsCHEMISTRY - A EUROPEAN JOURNAL, Issue 34 2010Dr. Yuetao Zhang Abstract This contribution describes the development and demonstration of the ambient-temperature, high-speed living polymerization of polar vinyl monomers (M) with a low silylium catalyst loading (, 0.05,mol,% relative to M). The catalyst is generated in situ by protonation of a trialkylsilyl ketene acetal (RSKA) initiator (I) with a strong Brønsted acid. The living character of the polymerization system has been demonstrated by several key lines of evidence, including the observed linear growth of the chain length as a function of monomer conversion at a given [M]/[I] ratio, near-precise polymer number-average molecular weight (Mn, controlled by the [M]/[I] ratio) with narrow molecular weight distributions (MWD), absence of an induction period and chain-termination reactions (as revealed by kinetics), readily achievable chain extension, and the successful synthesis of well-defined block copolymers. Fundamental steps of activation, initiation, propagation, and catalyst "self-repair" involved in this living polymerization system have been elucidated, chiefly featuring a propagation "catalysis" cycle consisting of a rate-limiting CC bond formation step and fast release of the silylium catalyst to the incoming monomer. Effects of acid activator, catalyst and monomer structure, and reaction temperature on polymerization characteristics have also been examined. Among the three strong acids incorporating a weakly coordinating borate or a chiral disulfonimide anion, the oxonium acid [H(Et2O)2]+[B(C6F5)4], is the most effective activator, which spontaneously delivers the most active R3Si+, reaching a high catalyst turn-over frequency (TOF) of 6.0×103,h,1 for methyl methacrylate polymerization by Me3Si+ or an exceptionally high TOF of 2.4×105,h,1 for n -butyl acrylate polymerization by iBu3Si+, in addition to its high (>90,%) to quantitative efficiencies and a high degree of control over Mn and MWD (1.07,1.12). An intriguing catalyst "self-repair" feature has also been demonstrated for the current living polymerization system. [source] | |||||||||||||