聚D，L-乳酸的体外可降解性能

In Vitro Degradation of Poly(D,L-Lactic Acid)

研究了中等分子量(-Mη=1.10×105)的聚D,L-乳酸在体外不同环境中的可降解性能,包括不同pH值溶液(37℃)和自然土壤。降解性能采用失重率、分子量变化、溶液pH值变化等来进行评价,并对试样表面形貌采用扫描电镜(SEM)进行了观察。结果表明:聚D,L-乳酸在体外环境中具有良好的可降解性,受降解环境的影响较大;失重和分子量的减小并不平行;在不同pH值溶液和土壤中的分子量变化在一定时间内符合一级反应动力学,且随溶液pH值的增大,降解速率减小。

The degradation of poly （D, L-lactic acid） with medium molecular weight in different solution （pH = 4.7, 7.4 and 10.4） at 37 ℃ and soil was investigated. The degradation rate was estimated by the mass loss, molecular weight reduction and pH value changes. The appearance of film was observed through SEM. The results indicate that poly （D, L-lactic acid） is of good degradation in vitro and the degradable performance is influenced by the medium. The mass loss and molecular reduction were not parallel. The kinetics of molecular weight reduction in solution and soil is accord to one order. Moreover, the degradable rate decreases with the increasing of solution pH value.