聚乳酸的热降解和稳定性研究  

Thermal Degradability and Stability of Poly(lactic acid)

作　　者：王彪[1] 万同[1] 曾威[1] 

机构地区：[1]天津科技大学材料科学与化学工程学院,天津300457

出　　处：《高分子通报》2015年第7期57-64,共8页Polymer Bulletin

基　　金：天津市高校第一批"优秀青年教师资助计划"资助

摘　　要：通过凝胶渗透色谱(GPC)和流变学手段研究了光学稳定剂UV-944、UV-531、UV-9、抗氧剂7910以及甲基丙烯酸缩水甘油酯(GMA)和亚磷酸三苯酯(TPP)六种助剂对聚乳酸(PLA)的的热降解和热稳定性的影响。结果表明:PLA粒料经混炼压片后重均分子量由13.6万下降至10.1万;经过180℃下热处理5h,纯PLA的重均分子量由10.1万下降至3.7万,而填加0.25%(wt)的TPP可使PLA基体的重均分子量由10.1万下降至9.1万;TPP含量为0.25%(wt)样品的储能模量和复数粘度在整个研究时间范围内均保持稳定不变。这些结果表明,TPP的引入有效地阻止了PLA的热降解。UV-944和抗氧剂7910改性PLA样品的重均分子量分别保持在13.3万和12.1万左右,有效地改善了基体的热稳定性。复配助剂UV-944+7910对于PLA基体热稳定性的提高具有协同作用,其效果优于各单一助剂,其它复配助剂均对PLA基体热稳定性的改善效果不佳。The poly（lactic acid） （PLA） was modified with three kinds of light stabilizer, UV-944, UV-531, UV-9 and antioxidant 7910, glycidyl methacrylate （GMA） and Triphenyl phosphate （TPP）. The thermal stabilities of all modified specimens were studied by gel permeation chromatography （GPC） and rheological tests. The results showed that weight- average molecular weights of neat PLA pellet declined from 136000 to 101000 by melt-blending and press-molding. After heat treatment at 180℃ for 5h, weight-average molecular weight of pure PLA declined from 101000 to 37000, while that of PLA modified with 0.25% （wt） TPP decreased from 101000 to 91000. The storage modulus and complex viscosity of PLA modified with 0. 25 % （wt） TPP remained constant within the studied range. These results indicate that the introduction of TPP effectively prevent thermal degradation of PLA. Weight-average molecular weights of PLA modified with UV-944 and antioxidant 7910 were maintained at about 133000 and 121000, respectively. UV-944 and antioxidant 7910 effectively improve the thermal stability of the PLA matrix. UV-944 and antioxidant 7910 together have a synergetic effect on the improved thermal stability of PLA, while other compound additives have little improvement on thermal stability of the matrix.

关 键 词：聚乳酸 热稳定性 助剂 分子量 

分 类 号：O633.14[理学—高分子化学]