聚DL-乳酸的合成与降解性能研究

以辛酸亚锡为催化剂，采用丙交酯的开环聚合法合成了聚DL-乳酸（PDLLA），并采用正交试验法分析了反应温度、聚合时间和催化剂用量等因素对聚合产物相对分子质量的影响。探讨了聚DL-乳酸在20～120min、180～210℃及不同环境中的热降解性能，研究了聚合物存体外模拟的生物环境中的降解特性。结果表明，当聚合温度为165℃，聚合时间为46h，催化剂用量为0．03％时聚乳酸的相对分子质量可达到21．4×10^4。在一定温度下，聚DL-乳酸的相对分子质量随热降解时间的延长而下降；聚乳酸在空气中的热降解速率比在真空中的热降解速率快。

Synthesis and Degradation Behavior of Poly DL-Lactide

Poly （ DL - lactide） （1）DLLA） was prepared by ring - opening polymerization of DL - lactide with catalyst stannous octoate. The influences of catalyst, temperature and time of polymerization on molecular weight of the product were researched by orthugonal test. The thermal degradation behavior of PDLLA at 180 -210℃, 20 - 120min and different environments was discussed, The degradation behavior in vitro simulated bioenvironmental condition was studied. The results indicated that the molecular weight of PDLLA could reach 21.4 ~ 104 while the temperature was 165℃, the catalyst amount was 0.03% （weight of L - lactide） and the polymerization time was 46 hours. The molecular weight of poly - lactide decreased while prolonging the thermal degradation time at a certain temperature. The rate of thermal degradation in vacuum was quicker than that of in air.