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
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 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.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.
