A new biodegradable PtBA-PHB-PtBA triblock copolymer was successfully synthesized by ATRP method with Br-PHB-Br as macroinitiator,tert-butyl acrylate as monomer and CuBr/PMDETA as the catalyst system.Cleavage of the t...A new biodegradable PtBA-PHB-PtBA triblock copolymer was successfully synthesized by ATRP method with Br-PHB-Br as macroinitiator,tert-butyl acrylate as monomer and CuBr/PMDETA as the catalyst system.Cleavage of the tert-butyl ether groups of the PtBA-PHB-PtBA triblock copolymer was then performed via hydrolysis with trifluoroacetic acid as the catalyst in dichloromethane to afford the amphiphilic PAA-PHB-PAA triblock copolymer.The hydrolysis is successful but trace tert-butyl ether groups still remain in the backbone.The molecular weight characteristics and chain structures were conformed by GPC and NMR,respectively.Because of hydrophilic and biocompatibility,the amphiphilic triblock copolymers have potential applications in the field of drug release.展开更多
Self assembly of an amphiphilic diblock copolymer polysyrene b polyvinylbenzoic acid in ethanol,which is a selective solvent for the polybenzoic acid segment was studied by means of transmission electron microscopy.Th...Self assembly of an amphiphilic diblock copolymer polysyrene b polyvinylbenzoic acid in ethanol,which is a selective solvent for the polybenzoic acid segment was studied by means of transmission electron microscopy.The diblock copolymers can self assemble into nano scale aggregates with polystyrene segment as the core and polyvinylbenzoic acid segment as the corona.The morphology of the aggregates is mainly controlled by the ratio of the two segment of the diblock copolymer.As the content of the ethanol insoluble polystyrene segment increased,the morphology can be changed from spheres to rods.The diameter of the aggregates increases slightly with concentration and decreases with the addition of CoCl 2 salt.展开更多
文摘A new biodegradable PtBA-PHB-PtBA triblock copolymer was successfully synthesized by ATRP method with Br-PHB-Br as macroinitiator,tert-butyl acrylate as monomer and CuBr/PMDETA as the catalyst system.Cleavage of the tert-butyl ether groups of the PtBA-PHB-PtBA triblock copolymer was then performed via hydrolysis with trifluoroacetic acid as the catalyst in dichloromethane to afford the amphiphilic PAA-PHB-PAA triblock copolymer.The hydrolysis is successful but trace tert-butyl ether groups still remain in the backbone.The molecular weight characteristics and chain structures were conformed by GPC and NMR,respectively.Because of hydrophilic and biocompatibility,the amphiphilic triblock copolymers have potential applications in the field of drug release.
文摘Self assembly of an amphiphilic diblock copolymer polysyrene b polyvinylbenzoic acid in ethanol,which is a selective solvent for the polybenzoic acid segment was studied by means of transmission electron microscopy.The diblock copolymers can self assemble into nano scale aggregates with polystyrene segment as the core and polyvinylbenzoic acid segment as the corona.The morphology of the aggregates is mainly controlled by the ratio of the two segment of the diblock copolymer.As the content of the ethanol insoluble polystyrene segment increased,the morphology can be changed from spheres to rods.The diameter of the aggregates increases slightly with concentration and decreases with the addition of CoCl 2 salt.
