Two opposing explanations to significant rate retardation in dithioester-mediated polymerization with reversible addition fragmentation chain transfer process(RAFT),e.g: slow fragmentation of intermediate radicals (Mo...Two opposing explanations to significant rate retardation in dithioester-mediated polymerization with reversible addition fragmentation chain transfer process(RAFT),e.g: slow fragmentation of intermediate radicals (Model A),and cross termination between intermediates and growing radicals (Model B),had been proposed by Davis and Monteiro independently. In this paper,a comparison of simulation results of Model A and Model B with experiment results was presented. The simulated results show that the intermediate concentration of Model A is much higher than that of experiments,while Model B gives a rather high polymerization rate than experiments with large concentration of dithioesters. The reaction model was better fitted,in light of kinetics,intermediate concentration and distribution of molecular weight,to experimental data when both cross termination and slow fragmentation were taken into account. [WT5HZ]展开更多
Monte Carlo simulation is applied, with a high effectiveness and versatility, to the studies on the kinetics and chain length distribution in radical polymerization with RAFT process. The results show that the molecul...Monte Carlo simulation is applied, with a high effectiveness and versatility, to the studies on the kinetics and chain length distribution in radical polymerization with RAFT process. The results show that the molecular weight the resulting polymers increase linearly with monomer conversion, and the polydispersity is lower than 1.1, a typical feature of living polymerization. The simulation results are in consistent with the experimental results in literature. Additionally, that the molecular weight is proportional to the initial concentration of dithioester, [DSE]0, and the polymerization rate is [DSE]0-independent, could be of great help for controlling molecular weight in experiment.展开更多
文摘Two opposing explanations to significant rate retardation in dithioester-mediated polymerization with reversible addition fragmentation chain transfer process(RAFT),e.g: slow fragmentation of intermediate radicals (Model A),and cross termination between intermediates and growing radicals (Model B),had been proposed by Davis and Monteiro independently. In this paper,a comparison of simulation results of Model A and Model B with experiment results was presented. The simulated results show that the intermediate concentration of Model A is much higher than that of experiments,while Model B gives a rather high polymerization rate than experiments with large concentration of dithioesters. The reaction model was better fitted,in light of kinetics,intermediate concentration and distribution of molecular weight,to experimental data when both cross termination and slow fragmentation were taken into account. [WT5HZ]
文摘Monte Carlo simulation is applied, with a high effectiveness and versatility, to the studies on the kinetics and chain length distribution in radical polymerization with RAFT process. The results show that the molecular weight the resulting polymers increase linearly with monomer conversion, and the polydispersity is lower than 1.1, a typical feature of living polymerization. The simulation results are in consistent with the experimental results in literature. Additionally, that the molecular weight is proportional to the initial concentration of dithioester, [DSE]0, and the polymerization rate is [DSE]0-independent, could be of great help for controlling molecular weight in experiment.
