An overview of aqueous polymerizations, which include emulsion, miniemulsion and suspension polymerizations, under stable free radical polymerization (SFRP) conditions is presented. The success of miniemulsion and sus...An overview of aqueous polymerizations, which include emulsion, miniemulsion and suspension polymerizations, under stable free radical polymerization (SFRP) conditions is presented. The success of miniemulsion and suspension SFRP polymerizations is contrasted with the difficulties associated with obtaining a stable emulsion polymerization. A recently developed unique microprecipitation technique is referenced as a means of making submicron sized particles that can be used to achieve a stable emulsion SFRP process.展开更多
The first TEMPO-mediated 'living' free radical polymerization of liquid crystalline monomer, 2, 5-bis[(4-methoxyphenyl)oxycarbonyl]styrene (MPCS), was carried out at 130 degrees C with BPO as an initiator. The...The first TEMPO-mediated 'living' free radical polymerization of liquid crystalline monomer, 2, 5-bis[(4-methoxyphenyl)oxycarbonyl]styrene (MPCS), was carried out at 130 degrees C with BPO as an initiator. The molecular weight of the polymer can be varied from rather low values to high values while maintaining narrow polydispersity. It was observed that the polymerization of MPCS proceeded much faster than that of styrene. A tentative explanation for this fast polymerization was suggested.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 synthesis of rod-coil diblock copolymers was achieved for the first time by TEMPO-mediated 'living' free radical polymerization of styrene and 2,5-bis [(4-methoxyphenyl)oxycarbonyl] styrene(MPCS). The blo...The synthesis of rod-coil diblock copolymers was achieved for the first time by TEMPO-mediated 'living' free radical polymerization of styrene and 2,5-bis [(4-methoxyphenyl)oxycarbonyl] styrene(MPCS). The block architecture of the two diblock copolymers thus prepared, MPCS-b-St(5400/2400) and MPCS-b-St(10800/8700), was confirmed by GPC, DSC studies and the formation of multimolecular micelles. (Author abstract) 10 Refs.展开更多
A novel environment-friendly system is proposed to fabricate polymer brush, which has the advantages including non-toxic and inexpensive initiator （eosin Y）, visible-light exposure （λ = 515 nm）, water medium and ...A novel environment-friendly system is proposed to fabricate polymer brush, which has the advantages including non-toxic and inexpensive initiator （eosin Y）, visible-light exposure （λ = 515 nm）, water medium and ambient environment. The experimental results from UV-Vis spectroscopy, AFM-based single molecule force spectroscopy （SMFS） and other measurements indicate that a polymer brush with a living nature is fabricated via free radical polymerization. This polymer brush may find applications in coatings, bio-interfaces and so forth.展开更多
Free radical polymerization and living ion polymerization have been simulated via the dynamic Monte Carlo method with the bond-fluctuation model in this paper. The polymeriza-tion-related parameters such as conversion...Free radical polymerization and living ion polymerization have been simulated via the dynamic Monte Carlo method with the bond-fluctuation model in this paper. The polymeriza-tion-related parameters such as conversion of monomers, degree of polymerization, average molecular weight and its distribution are obtained by statistics. The simulation outputs are con-sistent with the corresponding theoretical predictions. The scaling relationships of the coil size versus chain length are also confirmed at different volume fractions. Furthermore, the effect of diffusion on polymerization is revealed preliminarily in our simulation. Hence the simulation ap-proach has been proven to be feasible to investigate polymerization reactions with the advan-tages that configuration and diffusion of polymer chains can be examined together with polym-erization kinetics.展开更多
文摘An overview of aqueous polymerizations, which include emulsion, miniemulsion and suspension polymerizations, under stable free radical polymerization (SFRP) conditions is presented. The success of miniemulsion and suspension SFRP polymerizations is contrasted with the difficulties associated with obtaining a stable emulsion polymerization. A recently developed unique microprecipitation technique is referenced as a means of making submicron sized particles that can be used to achieve a stable emulsion SFRP process.
基金This work was supported by the Foundation of Peking University for Young Scientist and the National Natural Science Foundation of China(Grant No.29874003).
文摘The first TEMPO-mediated 'living' free radical polymerization of liquid crystalline monomer, 2, 5-bis[(4-methoxyphenyl)oxycarbonyl]styrene (MPCS), was carried out at 130 degrees C with BPO as an initiator. The molecular weight of the polymer can be varied from rather low values to high values while maintaining narrow polydispersity. It was observed that the polymerization of MPCS proceeded much faster than that of styrene. A tentative explanation for this fast polymerization was suggested.
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.
基金This project was supported by the Foundation of Peking University for Young Scientist and the National Natural Science Foundation of China.
文摘The synthesis of rod-coil diblock copolymers was achieved for the first time by TEMPO-mediated 'living' free radical polymerization of styrene and 2,5-bis [(4-methoxyphenyl)oxycarbonyl] styrene(MPCS). The block architecture of the two diblock copolymers thus prepared, MPCS-b-St(5400/2400) and MPCS-b-St(10800/8700), was confirmed by GPC, DSC studies and the formation of multimolecular micelles. (Author abstract) 10 Refs.
基金supported by the National Natural Science Foundation of China(No.21222401)the Sichuan Youth Science&Technology Foundation(No.2017JQ0009)
文摘A novel environment-friendly system is proposed to fabricate polymer brush, which has the advantages including non-toxic and inexpensive initiator （eosin Y）, visible-light exposure （λ = 515 nm）, water medium and ambient environment. The experimental results from UV-Vis spectroscopy, AFM-based single molecule force spectroscopy （SMFS） and other measurements indicate that a polymer brush with a living nature is fabricated via free radical polymerization. This polymer brush may find applications in coatings, bio-interfaces and so forth.
基金supported by the National Natural Science Foundation of China(Grant Nos.29825109,20174006,20221402,20374015,and Two-Base Grant)the Key Grant of Chinese Ministry of Education(Grant No.305004)+2 种基金the Award Foundation for Young Teachers from the Ministry of Education of China,973 Project(Grant No.G1999054306-03)863 Project(Grant No.2004AA215170)the Science and Technology Developing Foundation of Shanghai(Grant No.04JC14019).
文摘Free radical polymerization and living ion polymerization have been simulated via the dynamic Monte Carlo method with the bond-fluctuation model in this paper. The polymeriza-tion-related parameters such as conversion of monomers, degree of polymerization, average molecular weight and its distribution are obtained by statistics. The simulation outputs are con-sistent with the corresponding theoretical predictions. The scaling relationships of the coil size versus chain length are also confirmed at different volume fractions. Furthermore, the effect of diffusion on polymerization is revealed preliminarily in our simulation. Hence the simulation ap-proach has been proven to be feasible to investigate polymerization reactions with the advan-tages that configuration and diffusion of polymer chains can be examined together with polym-erization kinetics.
