A novel dualfunctional monomer, 2-（2＇,2＇,6＇,6＇-tetramethyl-piperidinyl-1＇-oxy）methylbenzene-1,4-dioyl chloride hydrochloride, with two acid chloride groups for step-growth polymerization and a nitroxide group f...A novel dualfunctional monomer, 2-（2＇,2＇,6＇,6＇-tetramethyl-piperidinyl-1＇-oxy）methylbenzene-1,4-dioyl chloride hydrochloride, with two acid chloride groups for step-growth polymerization and a nitroxide group for the mediation of living radical polymerization was synthesized. It was first copolymerized with terephthaloyl chloride and p- phenylenediamine at a feed molar ratio of 1：3：4 in N-methyl-2-pyrrolidone containing 10 wt% calcium chloride at -10℃ to yield a poly（p-phenylene terephthalamide） based macroinitiator, which initiated radical polymerization of styrene at 125℃ to obtain a series of poly（p-phenylene terephthalamide）-g-polystyrenes. A combinatory analysis of proton nuclear magnetic resonance spectroscopy, Fourier transform infrared spectroscopy, elementary analysis, thermogravimetry and gel permeation chromatography indicated that the macroinitiator induced the radical polymerization of styrene to proceed in a well- controlled way. The molecular weight of side-chains increased with an increase of monomer conversion, and the molecular weight distribution index remained lower than 1.5. The graft copolymers showed a remarkably improved solubility in N- methyl-2-pyrrolidone and much depressed crystallinity in bulk.展开更多
Polystyrene macromonomers with different molecular weight were prepared by radical polymerization of styrene(St) in benzene using β-methacryloxylethyl 2-N,N-diethyldithiocarbamylacetate (MAEDCA) as a monomer-iniferte...Polystyrene macromonomers with different molecular weight were prepared by radical polymerization of styrene(St) in benzene using β-methacryloxylethyl 2-N,N-diethyldithiocarbamylacetate (MAEDCA) as a monomer-iniferter.Characterization of the macromonomer by ~1H-NMR showed that the end groups were α-methacrylyoxylethyloxycarbonyl-methyl and ω-(N,N-diethyldithiocarbamyl). The macromonomer was difficult to homopolymerize, but it was easilycopolymerized with methyl methacrylate (MMA) initiated by AIBN to form graft copolymers (PMMA-g-PSt) with PStbranches randomly distributed along the PMMA backbone. Copolymerization reaction and the structure of the graft copolymers were strongly affected by M_n and concentration of the macromonomer. The composition and M_n of the purified graft copolymer were determined by ~1H-NMR and GPC analysis.展开更多
Copolymer of acrylic acid grafted polyethylene is used as membrane of ion exchanger.Its preparation and application were reported in many articles. However, its characterization was reported by only a few. In the pres...Copolymer of acrylic acid grafted polyethylene is used as membrane of ion exchanger.Its preparation and application were reported in many articles. However, its characterization was reported by only a few. In the present work, the copolymer is studied with X-ray photoelectron spectroscopy （XPS）. It is shown from the shift of the carboxyl group position in the spectra of C1s level that there are hydrogen-bonds in the copolymer. The grafting degree was characterized by the ratio of different carbon peak areas in the C1s spectra. Therefore, this method is very useful for the qualitative and quantitative展开更多
Although there is already an expression for the weight average molecular weight of block copolymers, the term defined by Rempp and Benoit in the expression is still ambiguous, It is impossible to calculate numerically...Although there is already an expression for the weight average molecular weight of block copolymers, the term defined by Rempp and Benoit in the expression is still ambiguous, It is impossible to calculate numerically the weight average molecular weight for a block copolymer with this expression; besides, the important inequality named after展开更多
In our previous two works we were mainly concerned with the synthesis and polymerization of two types of new bioactive acrylic esters: 3-acrylato-4-oxo-3, 4-dihydro-1, 2, 3-benzotriazines and N-p-acryloxtobenzoyloxysu...In our previous two works we were mainly concerned with the synthesis and polymerization of two types of new bioactive acrylic esters: 3-acrylato-4-oxo-3, 4-dihydro-1, 2, 3-benzotriazines and N-p-acryloxtobenzoyloxysuccinimides and the use of the latter copolymer for the immobilization of serum protein.展开更多
基金supported by the National Natural Science Foundation of China(No.20774001)the National Science Fund for Distinguished Young Scholars(No.20325415)
文摘A novel dualfunctional monomer, 2-（2＇,2＇,6＇,6＇-tetramethyl-piperidinyl-1＇-oxy）methylbenzene-1,4-dioyl chloride hydrochloride, with two acid chloride groups for step-growth polymerization and a nitroxide group for the mediation of living radical polymerization was synthesized. It was first copolymerized with terephthaloyl chloride and p- phenylenediamine at a feed molar ratio of 1：3：4 in N-methyl-2-pyrrolidone containing 10 wt% calcium chloride at -10℃ to yield a poly（p-phenylene terephthalamide） based macroinitiator, which initiated radical polymerization of styrene at 125℃ to obtain a series of poly（p-phenylene terephthalamide）-g-polystyrenes. A combinatory analysis of proton nuclear magnetic resonance spectroscopy, Fourier transform infrared spectroscopy, elementary analysis, thermogravimetry and gel permeation chromatography indicated that the macroinitiator induced the radical polymerization of styrene to proceed in a well- controlled way. The molecular weight of side-chains increased with an increase of monomer conversion, and the molecular weight distribution index remained lower than 1.5. The graft copolymers showed a remarkably improved solubility in N- methyl-2-pyrrolidone and much depressed crystallinity in bulk.
文摘Polystyrene macromonomers with different molecular weight were prepared by radical polymerization of styrene(St) in benzene using β-methacryloxylethyl 2-N,N-diethyldithiocarbamylacetate (MAEDCA) as a monomer-iniferter.Characterization of the macromonomer by ~1H-NMR showed that the end groups were α-methacrylyoxylethyloxycarbonyl-methyl and ω-(N,N-diethyldithiocarbamyl). The macromonomer was difficult to homopolymerize, but it was easilycopolymerized with methyl methacrylate (MMA) initiated by AIBN to form graft copolymers (PMMA-g-PSt) with PStbranches randomly distributed along the PMMA backbone. Copolymerization reaction and the structure of the graft copolymers were strongly affected by M_n and concentration of the macromonomer. The composition and M_n of the purified graft copolymer were determined by ~1H-NMR and GPC analysis.
文摘Copolymer of acrylic acid grafted polyethylene is used as membrane of ion exchanger.Its preparation and application were reported in many articles. However, its characterization was reported by only a few. In the present work, the copolymer is studied with X-ray photoelectron spectroscopy （XPS）. It is shown from the shift of the carboxyl group position in the spectra of C1s level that there are hydrogen-bonds in the copolymer. The grafting degree was characterized by the ratio of different carbon peak areas in the C1s spectra. Therefore, this method is very useful for the qualitative and quantitative
文摘Although there is already an expression for the weight average molecular weight of block copolymers, the term defined by Rempp and Benoit in the expression is still ambiguous, It is impossible to calculate numerically the weight average molecular weight for a block copolymer with this expression; besides, the important inequality named after
文摘In our previous two works we were mainly concerned with the synthesis and polymerization of two types of new bioactive acrylic esters: 3-acrylato-4-oxo-3, 4-dihydro-1, 2, 3-benzotriazines and N-p-acryloxtobenzoyloxysuccinimides and the use of the latter copolymer for the immobilization of serum protein.
