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以N-(苄氧羰基)-L-天冬氨酸和亚硫酰氯反应制备了N-苄氧基天冬氨酸酐,将其与不同链长的二醇(乙二醇、二缩三乙二醇、聚乙二醇200和600)缩聚,合成了含端羟基的天冬氨酸-二醇交替预聚物(ASP-Di-ol)x;以其为大分子引发剂,辛酸亚锡为催化剂进行丙交酯/乙交酯(摩尔比75∶25)开环共聚,合成系列含侧氨基的天冬氨酸-二醇-聚乙丙交酯[PLGA-(ASP-Diol)x-PLGA]多元三嵌段共聚物.用FTIR,1HNMR,EA,DSC和GPC对共聚物结构进行表征.结果表明,影响预聚物分子量的主要因素不是二醇的分子量,而是其端羟基的活性.随着二醇链段长度增加,多元共聚物中氨基含量降低,玻璃化转变温度也明显下降.通过改变二醇链段的长度(或分子量)可有效地控制PLGA-(ASP-Diol)x-PLGA中侧氨基的密度及分布.
N-benzyloxy aspartic anhydride was prepared by the reaction of N- (benzyloxycarbonyl) -L-aspartic acid with thionyl chloride, which was reacted with diols of different chain lengths (ethylene glycol, triethylenetetramine Diol, polyethylene glycol 200 and 600) polycondensation, synthesis of a terminal hydroxyl-containing aspartic acid - glycol alternating prepolymer (ASP-Di-ol) x; as its macromolecular initiator, stannous octoate The polylactide [PLGA- (ASP-Diol) x-) was synthesized by ring-opening copolymerization of lactide / glycolide (molar ratio 75:25) PLGA] triblock copolymer was synthesized by the method of FTIR, 1HNMR, EA, DSC and GPC.The results showed that the main factor affecting the molecular weight of the prepolymer was not the molecular weight of the diol, but the hydroxyl group activity With the increase of diol chain length, the content of amino group in polybasic copolymer decreased and the glass transition temperature decreased obviously.The PLGA- (ASP-Diol) x was effectively controlled by changing the length (or molecular weight) Density and distribution of mid-side amino groups in PLGA.