Hydrogenation of SBS using RuCl 2(PPh 3) 3 as catalyst and PPh\-3 as ligand was studied for the first time.Hydrogenated Degree of hydrogenation of SEBS reaches 98%.RuCl 2(PPh 3) 3 which was used as catalyst has high a...Hydrogenation of SBS using RuCl 2(PPh 3) 3 as catalyst and PPh\-3 as ligand was studied for the first time.Hydrogenated Degree of hydrogenation of SEBS reaches 98%.RuCl 2(PPh 3) 3 which was used as catalyst has high activity and high selectivity (phenyl is not hydrogenated),and gel will not be formed.The band of C C was saturated.So that RuCl 2(PPh 3) 3 has high selectivity.It is shown that the thermal resistance was improved greatly by initial decomposition temperature.Rh Ru double metal new catalytic system has higher activity than Ru single metal system in hydrogenation of SBS.展开更多
Ethyl α,α dibromoacetate was confirmed to be a difunctional initiator for the atom transfer radical polymerization of n butyl acrylate by means of gel penetration chromatography. When the polymerization of n butyl a...Ethyl α,α dibromoacetate was confirmed to be a difunctional initiator for the atom transfer radical polymerization of n butyl acrylate by means of gel penetration chromatography. When the polymerization of n butyl acrylate was carried out at different molar ratios of ethyl α,α dibromoacetate and ethyl α bromopropionate with CuBr/2,2′ bipyridine as the catalyst, polymers with bimodal molecular weight distributions were obtained, consisting of two narrowly distributed fractions, one of which was of a molecular weight double the other. Poly( n butyl acrylate) obtained with ethyl α,α dibromoacetate as the difunctional initiator was further used as the macroinitiator for styrene and methyl methacrylate in the presence of CuBr/2,2′ bipyridine respectively to prepare ABA triblock copolymers. It was found that high blocking efficiency was obtained for styrene. However, the polymer with bimodal molecular weight distribution was obtained for methyl methacrylate with a low molecular weight peak corresponding to that of poly( n butyl acrylate) macroinitiator. If the blocking polymerization was conducted with CuCl/ 2,2′ bipyridine as the catalyst to replace CuBr/2,2′ bipyridine, a high blocking efficiency was also obtained. [WT5HZ]展开更多
Tri-block amphiphilic copolymers with hybrid architectures were synthesized by coupling linear （poly（ethylene） glycol）（PEG） and dendritic second-generation Fréchet-type poly（benzyl ether）（PBE） via the W...Tri-block amphiphilic copolymers with hybrid architectures were synthesized by coupling linear （poly（ethylene） glycol）（PEG） and dendritic second-generation Fréchet-type poly（benzyl ether）（PBE） via the Williamson reaction （Gisotv,et al. Angew Chem,Int Ed Engl,1992,31:1200～1202）.Our experimental study shows that the powerful two-dimensional （）1H- （）13C heteronuclear multiple-quantum correlation （HMQC） and two-dimensional （）1H- （）13C heteronuclear multiple-bond correlation （HMBC） NMR techniques rather than the classical one-dimensional （）1H and （）13C-NMR methods can provide clear evidence to verify the formation of the tri-block copolymers.In our measurements HMQC and HMBC NMR techniques directly detected the signal of ether bonds bridged in-between PBE dendrons and PEG blocks,therefore,the formation of the block copolymers are evidently confirmed in molecular level.This work also provides a general method to exactly confirm the formation of block copolymers.展开更多
An optically active rod coil rod triblock copolymer containing poly(ethylene oxide)(PEO) as the flexible segment and poly{(+) 2,5 bis[4′ ((s) 2 methyl butoxy) phenyl]styrene} (PMBPS) as the rigid segment,PMBPS b PEO ...An optically active rod coil rod triblock copolymer containing poly(ethylene oxide)(PEO) as the flexible segment and poly{(+) 2,5 bis[4′ ((s) 2 methyl butoxy) phenyl]styrene} (PMBPS) as the rigid segment,PMBPS b PEO b PMBPS,was synthesized via atom transfer radical polymerization.The PMBPS block had a stable helical conformation with an excess of screw sense in solution.The self assembly behavior of the triblock copolymer in dioxane/water mixed solvents was examined by means of TEM and turbidity measurements.The triblock copolymer molecules aggregated when water content in the system was about 2wt%. The higher the initial polymer concentrations,the lower the critical water content.They formed vesicles with highly dispersed outside diameters,but they had a relatively uniform wall thickness of (27±3) nm.展开更多
文摘Hydrogenation of SBS using RuCl 2(PPh 3) 3 as catalyst and PPh\-3 as ligand was studied for the first time.Hydrogenated Degree of hydrogenation of SEBS reaches 98%.RuCl 2(PPh 3) 3 which was used as catalyst has high activity and high selectivity (phenyl is not hydrogenated),and gel will not be formed.The band of C C was saturated.So that RuCl 2(PPh 3) 3 has high selectivity.It is shown that the thermal resistance was improved greatly by initial decomposition temperature.Rh Ru double metal new catalytic system has higher activity than Ru single metal system in hydrogenation of SBS.
文摘Ethyl α,α dibromoacetate was confirmed to be a difunctional initiator for the atom transfer radical polymerization of n butyl acrylate by means of gel penetration chromatography. When the polymerization of n butyl acrylate was carried out at different molar ratios of ethyl α,α dibromoacetate and ethyl α bromopropionate with CuBr/2,2′ bipyridine as the catalyst, polymers with bimodal molecular weight distributions were obtained, consisting of two narrowly distributed fractions, one of which was of a molecular weight double the other. Poly( n butyl acrylate) obtained with ethyl α,α dibromoacetate as the difunctional initiator was further used as the macroinitiator for styrene and methyl methacrylate in the presence of CuBr/2,2′ bipyridine respectively to prepare ABA triblock copolymers. It was found that high blocking efficiency was obtained for styrene. However, the polymer with bimodal molecular weight distribution was obtained for methyl methacrylate with a low molecular weight peak corresponding to that of poly( n butyl acrylate) macroinitiator. If the blocking polymerization was conducted with CuCl/ 2,2′ bipyridine as the catalyst to replace CuBr/2,2′ bipyridine, a high blocking efficiency was also obtained. [WT5HZ]
基金Foundation item：Supported by the National Natural Science Foundation of China（20134020）,Science Research Fund of the Chinese Ministry of Education（104005）,Science Research Fund of Shandong Provincial Education Department of China（J05D11）Science Research Fund of Shandong Jiaotong University（Z200617）
文摘Tri-block amphiphilic copolymers with hybrid architectures were synthesized by coupling linear （poly（ethylene） glycol）（PEG） and dendritic second-generation Fréchet-type poly（benzyl ether）（PBE） via the Williamson reaction （Gisotv,et al. Angew Chem,Int Ed Engl,1992,31:1200～1202）.Our experimental study shows that the powerful two-dimensional （）1H- （）13C heteronuclear multiple-quantum correlation （HMQC） and two-dimensional （）1H- （）13C heteronuclear multiple-bond correlation （HMBC） NMR techniques rather than the classical one-dimensional （）1H and （）13C-NMR methods can provide clear evidence to verify the formation of the tri-block copolymers.In our measurements HMQC and HMBC NMR techniques directly detected the signal of ether bonds bridged in-between PBE dendrons and PEG blocks,therefore,the formation of the block copolymers are evidently confirmed in molecular level.This work also provides a general method to exactly confirm the formation of block copolymers.
文摘An optically active rod coil rod triblock copolymer containing poly(ethylene oxide)(PEO) as the flexible segment and poly{(+) 2,5 bis[4′ ((s) 2 methyl butoxy) phenyl]styrene} (PMBPS) as the rigid segment,PMBPS b PEO b PMBPS,was synthesized via atom transfer radical polymerization.The PMBPS block had a stable helical conformation with an excess of screw sense in solution.The self assembly behavior of the triblock copolymer in dioxane/water mixed solvents was examined by means of TEM and turbidity measurements.The triblock copolymer molecules aggregated when water content in the system was about 2wt%. The higher the initial polymer concentrations,the lower the critical water content.They formed vesicles with highly dispersed outside diameters,but they had a relatively uniform wall thickness of (27±3) nm.
