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
In order to clarify whether Atom Transfer Radical Polymerization（ATRP） method could be extended to free radical ring-opening polymerization, the polymerization of a kind of unsaturated cyclic acetal: 5,6-benzo-2-met...In order to clarify whether Atom Transfer Radical Polymerization（ATRP） method could be extended to free radical ring-opening polymerization, the polymerization of a kind of unsaturated cyclic acetal: 5,6-benzo-2-methylene-1,3-dioxepane（BMDO） in the presence of α,α-dibromoxylene as the initiator and CuBr/2,2-bipyridine as the catalyst and ligand at 120 ℃ was investigated. IR, 1H NMR and 13C NMR spectra of the polymer obtained showed that BMDO underwent quantitatively ring-opening polymerization and linear polyesters were prepared. GPC curves indicated that the polyesters had a narrower molecular weight distribution. Molecular weight of the polyesters could be controlled by polymerization time and adjusting the molar ratio of monomer/intiator consumed. The polymers with narrower polydispersities were obtained, and first-order kinetics of polymerization was observed. These facts proved that BMDO underwent “living” free radical ring-opening polymerization. And this is the firsr report on the “living” free radical ring-opening polymerization of unsarurated cyclic acetal using atom transfer radical polymerization method. The results of ln（[M]0）/[M]) against polymerization time, Mn vs. conversion, and molecular weight distribution of the polymers are indicative of the “living” polymerization process.展开更多
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.
文摘In order to clarify whether Atom Transfer Radical Polymerization（ATRP） method could be extended to free radical ring-opening polymerization, the polymerization of a kind of unsaturated cyclic acetal: 5,6-benzo-2-methylene-1,3-dioxepane（BMDO） in the presence of α,α-dibromoxylene as the initiator and CuBr/2,2-bipyridine as the catalyst and ligand at 120 ℃ was investigated. IR, 1H NMR and 13C NMR spectra of the polymer obtained showed that BMDO underwent quantitatively ring-opening polymerization and linear polyesters were prepared. GPC curves indicated that the polyesters had a narrower molecular weight distribution. Molecular weight of the polyesters could be controlled by polymerization time and adjusting the molar ratio of monomer/intiator consumed. The polymers with narrower polydispersities were obtained, and first-order kinetics of polymerization was observed. These facts proved that BMDO underwent “living” free radical ring-opening polymerization. And this is the firsr report on the “living” free radical ring-opening polymerization of unsarurated cyclic acetal using atom transfer radical polymerization method. The results of ln（[M]0）/[M]) against polymerization time, Mn vs. conversion, and molecular weight distribution of the polymers are indicative of the “living” polymerization process.
