直接缩聚法合成聚乳酸工艺中三种锡类催化剂对比研究

Comparison of Tin and Its Two Chemical Compounds as Catalyst in Direct Polycondensation Process of Polylactic Acid

以D,L-乳酸为原料,采用直接缩聚法合成聚乳酸,分别探讨了锡、氯化亚锡、辛酸亚锡为催化剂对聚乳酸分子量的影响。结果表明,辛酸亚锡为最佳催化剂,在辛酸亚锡用量(按乳酸质量计)为0.8%、135℃低温聚合阶段反应15min、175℃高温聚合阶段(真空度为0.085 MPa)反应8 h的条件下,合成的聚乳酸无氧化、变色现象,粘均分子量(Mη)可达30 481。

Using D, L-lactic acid as raw material, polylactic acid was synthesized by direct polycondensation method. The effects of tin, stannous chloride and stannous octanoate as catalyst respectively on the molecular weight of polylactic acid were investigated. The results showed that stannous octanoate was the optimum cata- lyst. Under the conditions as follows：the catalyst dosage was 0.8%, the lower polymerization lasted for 15 min at 135℃, the higher polymerization lasted for 8 h at 175℃ with vacuum degree of 0. 085 MPa, the obtained polylaetic acid didn＇t change colour without oxizadation, and its viscosity average molecular weight was 30 481.