【摘要】 以聚乙二醇(PEG)和N -苄氧羰基 -L- 天冬氨酸酐为原料,通过溶液缩聚法制备了聚(聚乙二醇 -co -L -天冬氨酸)交替预聚物(PEG- ASP) n;进一步以辛酸亚锡为催化剂、(PEG- ASP) n 为共引发剂引发D ,L- LA和GA开环共聚合成了带有侧氨基功能基团的PLGA (PEG- ASP) n 共聚物.用GPC、FT -IR、1 H -NMR、DSC等研究了共聚物的结构和性能.结果表明,共聚物表现为典型的无定形聚合物;(PEG- ASP) n 的含量对共聚物的性能有显著影响,随(PEG- ASP) n 含量增加,共聚物的亲水性增强,玻璃化转变温度(Tg)下降;以Pd(5wt% ) C为催化剂,采用催化加氢方法可完全脱除共聚物侧氨基上的保护基团;脱除侧氨基上的保护基团后,共聚物的分子量和Tg 值均略有增大,亲水性有所提高.更多还原

【Abstract】 Poly(poly(ethylene glycol)-co-L-aspartic acid)(PEG-ASP) n alter nating p repolymer was first prepared by the solution polycondensation from N-(benzy loxy carbonyl)-L-aspartic acid anhydride and poly(ethylene glycol).Then,the nov el PL GA-(PEG-ASP) n copolymers with pendant amine functional groups were synth esized b y bulk ring-opening copolymerization of D,L-LA with GA using tin octoate(S n(Oc t) 2) as a catalyst,and (PEG-ASP) n prepolymer as a co-initiator.The str ucture a nd properties of the novel copolymers were studied by GPC,FT-IR, 1H-NMR a nd DSC,etc.Results showed that the PLGA-(PEG-ASP) n copolymers were t ypical amorphous polymers.The content of (PEG-ASP) n prepolymer had significant influence o n the properties of the copolymers.The hydrophilicity of the copolymers was improved a nd the value of the glass transition temperature(T g) decreased as the cont ent o f the prepolymer increased.The benzyloxycarbonyl(CB z) protecting groups of the co polymer were totally removed by catalytic transfer hydrogenation using palladium over activated carbon (5 wt%) as a catalyst and H 2 as an effective hydrogen do n or.The molecular weight,the value of T g and hydrophilicity of the copolyme r were somewhat increased as the CB z protecting groups were removed.更多还原