乳酸/聚乙二醇嵌段共聚物的合成与表征

Synthesis and Characterization of Block Copolymer of Lactic Acid/Polyethylene Glycol

利用直接缩聚法制备了乳酸与聚乙二醇的嵌段共聚物(PLEG)。采用正交试验法考察了乳酸与聚乙二醇质量比、催化剂种类、催化剂含量、反应温度和反应时间对PLEG性能的影响。结果显示优化的反应条件:乳酸与聚乙二醇质量比为8.5∶1.5,采用自制的复合催化剂,催化剂质量分数0.6%,聚合温度160℃,聚合时间5h。另外还考察了扩链剂对PLEG性能的影响,结果表明扩链剂能够显著提高PLEG的相对分子质量。对合成的PLEG通过红外光谱、核磁共振、热分析进行了表征。

Block copolymers of lactic acid with poly （ethylene glycol）（PLEG） were synthesized by melt polycondensation . Effects of the mass ratio of lactic acid to poly（ethylene glycol） , catalyst type, catalyst content, reaction temperature and reaction time on PLEG properties were investigated. The results show that the feasible synthetic conditions are the mass ratio of lactic acid to poly（ethylene glycol） 8.5 ： 1.5, stannous chloride-xylenesulfonic acid mixture as composite catalyst and the catalysts concentration of 0.6%, the. polymerization temperature of 160 ℃, the polymerization time of 5 h. Moreover, the effects of chain extender on PLEG properties were studied. The results show that the molecular mass increases remarkably when the chain extender is used. The PLEG is characterized by IR,NMR, TG and DTA.