天然氨基酸作用下丙交酯的开环聚合反应

研究了天然氨基酸作用下丙交酯的开环聚合反应，探讨了氨基酸的酸碱性、浓度、反应条件等对聚合物相对分子质量的影响。结果表明，碱性氨基酸作用下丙交酯的开环聚合可以进行；在D, L-丙交酯的开环聚合反应中，随着氨基酸碱性的增强，聚合物的相对分子质量增大；在反应时间为48 h、反应温度为150 ℃、D，L-丙交酯/L-赖氨酸=50/1（物质的量比，下同）的条件下，可得到重均相对分子质量为12800 g/mol、相对分子质量分布为2.11的聚丙交酯；在D，D-丙交酯和L，L-丙交酯的开环聚合反应中，氨基酸的碱性越强，得到的聚合物的消旋作用越明显。

Ring-opening Polymerization of Lactide in the Presence of Natural Amino Acids

The ring opening polymerization (ROP) of lactide in presence of amino acid was investigated. Effects of amino acid concentration, pH value, and reaction condition on the molecular weight of the polymer were discussed. For the ROP of D，L- lactide , the molecular weight of polymer increased with increasing basicity of amino acid. Under the condition of 150 °C for 48 h, when molar ratio of D，L-LA/L-lysine]=50/1, polymeric product with weight-average molecular weight of 12800 g/mol and polydispersity of / =2.11 was obtained. In the ROP of D, D- lactide and L, L- lactide, the racemization of the polymer increased with increasing basicity of amino acid.