Hyperbranched polyacrylate copolymers were synthesized by self\|condensing vinyl copolymerization (SCVCP) of 2\|[(2\|bromopropionyl)oxy]ethyl acrylate(BPEA) and methyl acrylate(MA) in the presence of a tetrafunctional...Hyperbranched polyacrylate copolymers were synthesized by self\|condensing vinyl copolymerization (SCVCP) of 2\|[(2\|bromopropionyl)oxy]ethyl acrylate(BPEA) and methyl acrylate(MA) in the presence of a tetrafunctional initiator(THABI).The structures of the polymers obtained were characterized by 1H\|NMR and SEC/refractive index(RI)/right anagle laser light scattering(RALLS)/differential viscometer(DV).Molecular weight(MW),molecular weight distribution(MWD) and degree of branching(DB) were influenced by conversion and initial feed molar ratio of BPEA,MA and THABI.The addition of THABI can narrow the MWDs of the polymers obtained.The results are consistent with our simulation result.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
The digital image processing technique was used for the extraction of physical information from the temporal image of phase structure in the process of phase separation in the blend of poly (butylene terephthalate-co-...The digital image processing technique was used for the extraction of physical information from the temporal image of phase structure in the process of phase separation in the blend of poly (butylene terephthalate-co-caprolactone )with polycarbonate. The power spectrum images of the two-dimensional Fourier transformation (2DFT) of the temporal image of phase structure reflect the change of the phase size with time.展开更多
A new type of liquid crystalline polyesters with resorcin as one part of the mesogenic unitconnected together by polymethylene, or phenylene group, and lateral groups consisting of arigid azobenzene as another part of...A new type of liquid crystalline polyesters with resorcin as one part of the mesogenic unitconnected together by polymethylene, or phenylene group, and lateral groups consisting of arigid azobenzene as another part of the mesogenic unit were synthesized by interfacialpolymerization of diacyl chlorides in 1, 2-dichloroethane and 2, 4-dihydroxy-4'-nitroazobenzen inaqueous alkaline solution. The polyester structures were confirmed by proton NMR and IRspectra. Their phase transition behavior and texture were studied by polarizing microscopy andDSC.展开更多
A new monomer, 3,9-diallyl-3, 9-dibenzyl-1, 5,7,11 - tetraoxa- spiro [5,5] undecane (6) was prepared by the reaction of 2- allyl- 2' - benzyl- propanediol - 1.3 with dibutyltin oxide, and then treated with CS_2. M...A new monomer, 3,9-diallyl-3, 9-dibenzyl-1, 5,7,11 - tetraoxa- spiro [5,5] undecane (6) was prepared by the reaction of 2- allyl- 2' - benzyl- propanediol - 1.3 with dibutyltin oxide, and then treated with CS_2. Monomer 4 could be initiated by cationic initiators to give a viscous polymer (white powder in the case of polymerization at 0℃). Upon the NMR and IR spectra of the obtained polymer, the components and their relative amount were estimated. The polymerization mechanism was discussed.展开更多
文摘Hyperbranched polyacrylate copolymers were synthesized by self\|condensing vinyl copolymerization (SCVCP) of 2\|[(2\|bromopropionyl)oxy]ethyl acrylate(BPEA) and methyl acrylate(MA) in the presence of a tetrafunctional initiator(THABI).The structures of the polymers obtained were characterized by 1H\|NMR and SEC/refractive index(RI)/right anagle laser light scattering(RALLS)/differential viscometer(DV).Molecular weight(MW),molecular weight distribution(MWD) and degree of branching(DB) were influenced by conversion and initial feed molar ratio of BPEA,MA and THABI.The addition of THABI can narrow the MWDs of the polymers obtained.The results are consistent with our simulation result.
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The digital image processing technique was used for the extraction of physical information from the temporal image of phase structure in the process of phase separation in the blend of poly (butylene terephthalate-co-caprolactone )with polycarbonate. The power spectrum images of the two-dimensional Fourier transformation (2DFT) of the temporal image of phase structure reflect the change of the phase size with time.
基金This work is supported by the Structure Research Laboratory,University of Science and Technology of China
文摘A new type of liquid crystalline polyesters with resorcin as one part of the mesogenic unitconnected together by polymethylene, or phenylene group, and lateral groups consisting of arigid azobenzene as another part of the mesogenic unit were synthesized by interfacialpolymerization of diacyl chlorides in 1, 2-dichloroethane and 2, 4-dihydroxy-4'-nitroazobenzen inaqueous alkaline solution. The polyester structures were confirmed by proton NMR and IRspectra. Their phase transition behavior and texture were studied by polarizing microscopy andDSC.
基金This project is supported by the National Natural Science Foundation of China
文摘A new monomer, 3,9-diallyl-3, 9-dibenzyl-1, 5,7,11 - tetraoxa- spiro [5,5] undecane (6) was prepared by the reaction of 2- allyl- 2' - benzyl- propanediol - 1.3 with dibutyltin oxide, and then treated with CS_2. Monomer 4 could be initiated by cationic initiators to give a viscous polymer (white powder in the case of polymerization at 0℃). Upon the NMR and IR spectra of the obtained polymer, the components and their relative amount were estimated. The polymerization mechanism was discussed.
