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Kinetic Simulations of Reversible Chain Transfer Catalyzed Polymerization (RTCP): Guidelines to Optimum Molecular Weight Control
Authors:Philipp Vana  Atsushi Goto
Abstract:Kinetic simulations of reversible chain transfer catalyzed polymerization (RTCP) were performed using the program package Predici. Mimicking the RTCP of styrene in bulk at 80 °C, the full molecular weight distributions, the polydispersities of resulting polymer and the time evolutions of monomer conversion and participating species were simulated. The influence of the kinetic coefficients governing the RTCP equilibrium – specifically, the rate coefficients of activation, ka, and deactivation, kda – on the controlled polymerization behavior was probed in detail by varying their respective simulation input values over five orders of magnitude. It was found that optimum results for molecular weight control are obtained for K = ka/kda in the range 1 to 10 and with ka and kda being of the order of 106 L · mol−1 · s−1 or above. The influence of degenerative chain transfer on the process was found to be significant only in poorly controlled systems, but is small in well‐controlled RTCP. Based on the finding that the catalyst is depleting during the polymerization due to cross‐termination, guidelines for obtaining high molecular weight material via repeated addition of catalyst were developed.
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Keywords:computer modeling  kinetics (polym  )  living polymerization  Predici  reversible chain transfer catalyzed polymerization (RTCP)  simulations
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