以二乙醇胺为共引发剂的PLA的合成与表征

以辛酸亚锡sn(oct)2]为催化剂，二乙醇胺(DEA)为共引发剂在130℃进行DL-丙交酯开环聚合环聚合36h,单体转化率平均约为75%,基本上与DEA投料比无关.^H NMR分析结果表明，DEA参与了引发丙交酯的开环聚合，DL-丙交酯是沿着DEA分子两端开环聚合，分子链的链端结构为以羟基为端基的丙交酯结构单元。聚合物的相对分子质量和Tg随DEA投料比增加而降低；^1H NMR法测定的相对分子质量均比根据投料比计算的小，这主要与聚合体系中由于杂质如水份和氧存在有关；与只用Sn(Oct)2催化聚合的聚丙交酯相比，用DEA作共引发剂而得的聚合物有更强的亲水性，且随着DEA投料比的增大而增强。

Synthesis and Characterization of Polylactide Using Diethylene Amine as Co-initiator

Stannous octoate (Sn(Oct)2) and diethanolamine(DEA)were chosen respectively as catalyst and co-initiator to initiate the polymerization of DL-lactide at 130 C for 36 h. The conversion of lactide was about 75% and basically independent of DEA feed ratio. Analysis by ' H NMR showed that DEA participated in initiation of the ring-opening polymerization of lactide and the lactide chains grew from both ends of the DEA molecules and ended with hydroxy-terminated lactide units. The molecular weight of the polymers and their Tg's were decreased with increasing DEA feed ratio. As the result of vaccum treatment for the reaction tube before sealing, the molecular weights of the polymers measured by H NMR were lower than those calculated according to the feeding ratios. Compared with the PM/LA prepared by using Sn (Oct)2 as catalyst alone, the PDLLAs synthesized in the presence of Sn (Oct)2 and DEA had higher hydrophilicity. And it enhanced as the the DEA feed ratio increased.