The reversible addition-fragmentation chain transfer （RAFT） miniemulsion polymerization of vinyl acetate （VAc） mediated by methyl （methoxycarbonothioyl） sulfanyl acetate （MMSA） was carried out. The results sho...The reversible addition-fragmentation chain transfer （RAFT） miniemulsion polymerization of vinyl acetate （VAc） mediated by methyl （methoxycarbonothioyl） sulfanyl acetate （MMSA） was carried out. The results showed that polymerizations initiated by AIBN and KPS proceeded in a controlled way. The RAFT miniemulsion polymerization of VAc initiated by KPS showed the shorter inhibition period, higher propagation rate coefficient and final conversion than those in experiment initiated by AIBN. When the monomer conversion reached 25%, the polydispersity index （PDI） of polymer became broad, which was related to chain transfer reaction in RAFT miniemulsion of VAc.展开更多
Reversible addition-fragmentation chain transfer(RAFT) mediated grafting of acrylonitrile onto Polyethylene/Poly(ethylene terephthalate)(PE/PET) composite fibers was performed using γ-irradiation as the initial sourc...Reversible addition-fragmentation chain transfer(RAFT) mediated grafting of acrylonitrile onto Polyethylene/Poly(ethylene terephthalate)(PE/PET) composite fibers was performed using γ-irradiation as the initial source at ambient temperature. Different initial concentrations of 2-cyanoprop-2-yl dithiobenzonate were used as the chain transfer agent. The kinetics of graft polymerization is in accordance with the living RAFT polymerization. The successful grafting of acrylonitrile is proved by Fourier transform infrared spectroscopy analysis.The results of monofilament tensile test show that mechanical properties of the fibers change slightly after grafting. Scanning electronic microscopy images of the fibers show that the surface of RAFT grafted fibers is smoother than that of fibers grafted conventionally.展开更多
Polystyrene-styrene/butadiene diblock copolymers were synthesized via reversible addition-fragmentation chain transfer （RAFT） miniemulsion polymerization.During the polymerization process,the molecular weight distri...Polystyrene-styrene/butadiene diblock copolymers were synthesized via reversible addition-fragmentation chain transfer （RAFT） miniemulsion polymerization.During the polymerization process,the molecular weight distribution was narrow and the numerical molecular weight of the copolymers increased with increasing conversion of monomers,which was close to the theoretical.FT-IR and ^1H NMR results indicated that the microstructure of the polymer was mainly 1,4-trans-butadiene with small amount of 1,2-units,and composition in the copolymers was obtained.展开更多
To make more homogenous organic monolithic structure, reversible addition-fragmentation chain transfer （RAFT） process was employed in the synthesis of the clenbuterol imprinted polymer. In the synthesis, the influen...To make more homogenous organic monolithic structure, reversible addition-fragmentation chain transfer （RAFT） process was employed in the synthesis of the clenbuterol imprinted polymer. In the synthesis, the influence of synthetic conditions on the polymer structure and separation efficiency was studied. The result demonstrated that the imprinted columns prepared with RAFT process have higher column efficiency and selectivity than the columns prepared with conventional polymerization in the present study, which may result from the higher surface area, smaller pore size and the narrower globule size distribution in their structures. The result indicated that RAFT polymerization provided better conditions for the clenbuterol imprinted monolithic polymer preparation. 2009 Xiang Chao Dong. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.展开更多
Effective molecularly imprinted membranes（MIMs） were developed as an efficient adsorbent for the selective removal ofp-hydroxybenzoic acid（p-HB） from acetylsalicylic acid（ASA, aspirin）. The MIMs were grafted suc...Effective molecularly imprinted membranes（MIMs） were developed as an efficient adsorbent for the selective removal ofp-hydroxybenzoic acid（p-HB） from acetylsalicylic acid（ASA, aspirin）. The MIMs were grafted successfully from poly（vinylidene fluoride） microfiltration membranes via reversible addition-fragmentation chain transfer（RAFT） polymerization. The graft copolymerization of acrylic acid（AA） in the presence of template p-hydroxybenzoic acid led to molecularly imprinted polymer（MIP） film coated membranes. The obtained MIMs were characterized by scanning electron microscopy（SEM）, Fourier transform infrared spectrophotometer（FTIR） and Raman spectra, and batch mode adsorption studies were carried ont to investigate the specific adsorption equilibrium, kinetics and selective recognition properties of different MIMs. The kinetic properties of the MIMs could be well described by the pseudo-second-order rate equation. Selective permeation experiments were performed to evaluate the permeation selectivity of the p-HB imprinted membranes. The observed performances of the MIMs are applicable to the further purification of aspirin. Keywords Acetylsalicylic acid; Reversible addition-fragmentation chain transfer; Molecularly imprinted membrane; p-Hydroxybenzoic acid; Selective adsorption展开更多
Bulk polymerization of styrene was carried out in the presence of a reversible addition fragmentation chain transfer (RAFT) of benzyl dithiobenzoate (BDB). The comparison between reaction systems with and without BDB ...Bulk polymerization of styrene was carried out in the presence of a reversible addition fragmentation chain transfer (RAFT) of benzyl dithiobenzoate (BDB). The comparison between reaction systems with and without BDB indicates that there is significant retardation in the reaction rate when BDB is used. The molecular weight of styrene polymer prepared with BDB shows linear relationship with the conversion of monomer, polydispersity is as narrow as 1.2, and no gel effects are observed during the polymerization with BDB, which are characteristics of a living radical polymerization. It has been found that the concentrations of BDB and azobis (isobutyronitrile) (AIBN) have opposite effects on the polymerization kinetics, and the AIBN dominates.展开更多
基金supported by the National Natural Science Foundation of China(No.20836007)
文摘The reversible addition-fragmentation chain transfer （RAFT） miniemulsion polymerization of vinyl acetate （VAc） mediated by methyl （methoxycarbonothioyl） sulfanyl acetate （MMSA） was carried out. The results showed that polymerizations initiated by AIBN and KPS proceeded in a controlled way. The RAFT miniemulsion polymerization of VAc initiated by KPS showed the shorter inhibition period, higher propagation rate coefficient and final conversion than those in experiment initiated by AIBN. When the monomer conversion reached 25%, the polydispersity index （PDI） of polymer became broad, which was related to chain transfer reaction in RAFT miniemulsion of VAc.
基金Supported by the National Natural Science Foundation of China(Nos.11475246 and 11175234)the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDA02030205)
文摘Reversible addition-fragmentation chain transfer(RAFT) mediated grafting of acrylonitrile onto Polyethylene/Poly(ethylene terephthalate)(PE/PET) composite fibers was performed using γ-irradiation as the initial source at ambient temperature. Different initial concentrations of 2-cyanoprop-2-yl dithiobenzonate were used as the chain transfer agent. The kinetics of graft polymerization is in accordance with the living RAFT polymerization. The successful grafting of acrylonitrile is proved by Fourier transform infrared spectroscopy analysis.The results of monofilament tensile test show that mechanical properties of the fibers change slightly after grafting. Scanning electronic microscopy images of the fibers show that the surface of RAFT grafted fibers is smoother than that of fibers grafted conventionally.
基金supported by Major Program of National Natural Science Foundation of China(No. 20836007)National Natural Science Foundation of China(No.20806067).
文摘Polystyrene-styrene/butadiene diblock copolymers were synthesized via reversible addition-fragmentation chain transfer （RAFT） miniemulsion polymerization.During the polymerization process,the molecular weight distribution was narrow and the numerical molecular weight of the copolymers increased with increasing conversion of monomers,which was close to the theoretical.FT-IR and ^1H NMR results indicated that the microstructure of the polymer was mainly 1,4-trans-butadiene with small amount of 1,2-units,and composition in the copolymers was obtained.
基金supported by the National Natural Science Foundation of China(No.20575030)
文摘To make more homogenous organic monolithic structure, reversible addition-fragmentation chain transfer （RAFT） process was employed in the synthesis of the clenbuterol imprinted polymer. In the synthesis, the influence of synthetic conditions on the polymer structure and separation efficiency was studied. The result demonstrated that the imprinted columns prepared with RAFT process have higher column efficiency and selectivity than the columns prepared with conventional polymerization in the present study, which may result from the higher surface area, smaller pore size and the narrower globule size distribution in their structures. The result indicated that RAFT polymerization provided better conditions for the clenbuterol imprinted monolithic polymer preparation. 2009 Xiang Chao Dong. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.
基金Supported by the National Natural Science Foundation of China（No.21606099）, the Natural Science Foundation of Jilin Province, China（No.20180623042TC） and the Science and Technology Research Foundation of the Department of Education of Jilin Province, China（Nos. JJKH20180 782KJ, JJKH20180761K J, JJKH20170376K J）.
文摘Effective molecularly imprinted membranes（MIMs） were developed as an efficient adsorbent for the selective removal ofp-hydroxybenzoic acid（p-HB） from acetylsalicylic acid（ASA, aspirin）. The MIMs were grafted successfully from poly（vinylidene fluoride） microfiltration membranes via reversible addition-fragmentation chain transfer（RAFT） polymerization. The graft copolymerization of acrylic acid（AA） in the presence of template p-hydroxybenzoic acid led to molecularly imprinted polymer（MIP） film coated membranes. The obtained MIMs were characterized by scanning electron microscopy（SEM）, Fourier transform infrared spectrophotometer（FTIR） and Raman spectra, and batch mode adsorption studies were carried ont to investigate the specific adsorption equilibrium, kinetics and selective recognition properties of different MIMs. The kinetic properties of the MIMs could be well described by the pseudo-second-order rate equation. Selective permeation experiments were performed to evaluate the permeation selectivity of the p-HB imprinted membranes. The observed performances of the MIMs are applicable to the further purification of aspirin. Keywords Acetylsalicylic acid; Reversible addition-fragmentation chain transfer; Molecularly imprinted membrane; p-Hydroxybenzoic acid; Selective adsorption
文摘Bulk polymerization of styrene was carried out in the presence of a reversible addition fragmentation chain transfer (RAFT) of benzyl dithiobenzoate (BDB). The comparison between reaction systems with and without BDB indicates that there is significant retardation in the reaction rate when BDB is used. The molecular weight of styrene polymer prepared with BDB shows linear relationship with the conversion of monomer, polydispersity is as narrow as 1.2, and no gel effects are observed during the polymerization with BDB, which are characteristics of a living radical polymerization. It has been found that the concentrations of BDB and azobis (isobutyronitrile) (AIBN) have opposite effects on the polymerization kinetics, and the AIBN dominates.
