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
This paper is the first report on the atom transfer radical copolymerization of unsaturated cyclic acetal, 4,7 dimethyl 2 methylene 1,3 dioxepane(DMMDO) and styrene(St) in the presence of α bromobutyrate as the initi...This paper is the first report on the atom transfer radical copolymerization of unsaturated cyclic acetal, 4,7 dimethyl 2 methylene 1,3 dioxepane(DMMDO) and styrene(St) in the presence of α bromobutyrate as the initiator and CuBr/2,2 bipyridine as the catalyst/ligand at 110 ℃ was investigated. Both DMMDO and St components could be found in main chains of the obtained polymer, and the copolymer had a narrow molecular weight distribution. DMMDO component in the copolymer contained both addition and ring opening units, thus the ester bond was introduced into the main chain, and the copolymer could be chemically degradable and biologically degradable.展开更多
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.
文摘This paper is the first report on the atom transfer radical copolymerization of unsaturated cyclic acetal, 4,7 dimethyl 2 methylene 1,3 dioxepane(DMMDO) and styrene(St) in the presence of α bromobutyrate as the initiator and CuBr/2,2 bipyridine as the catalyst/ligand at 110 ℃ was investigated. Both DMMDO and St components could be found in main chains of the obtained polymer, and the copolymer had a narrow molecular weight distribution. DMMDO component in the copolymer contained both addition and ring opening units, thus the ester bond was introduced into the main chain, and the copolymer could be chemically degradable and biologically degradable.
