双螺杆反应挤出法开环聚合制备聚乳酸的研究

摘要

Direct preparation of poly(L-lactic acid) (PLLA) by ring-opening polymerization of L-lactide using twin-screw extruder was carried out .The influence of the catalyst type and content , the polymerization temperature and the polymerization time on polymer properties were investigated .The results showed that the relative appropri-ate reaction conditions were as follows:2-ethylhexanoic acid tin ( II) salt was selected as the main catalyst and 1,do-decanol was selected as the cocatalyst , the polymerization temperature was 170℃, the molar ratio of monomer/cat-alyst was 3 000∶1 and the polymerization time was 120 min.Under the above conditions , the PLLA polymer with a molecular weight of about 5.3 ×104 could be obtained.The structure and thermal properties of polymer were char-acterized by FT-IR, 1 H-NMR, DSC and TG, etc.%以双螺杆挤出机为反应器来实施L-丙交酯的开环聚合制备聚乳酸，探讨了催化剂种类及其含量、聚合温度及聚合时间等因素对聚合产物性质的影响。实验获得的相对适宜的工艺条件如下：优选辛酸亚锡（Sn（Oct）2）／1-十二醇（CH3（CH2）11OH）为复合催化剂体系，单体与催化剂摩尔比为3000∶1，聚合温度为170℃，聚合时间为120 min，由此可获得粘均相对分子质量为5．3×104的聚（L-乳酸）。在此基础上，进一步采用 FT-IR、1H-NMR、DSC和 TG等分析手段对聚合产物的结构和热性能进行了表征。