聚乳酸扩链及热性能研究

Chain Extension and Thermal Analysis of Poly(L-lactic acid)

采用L-乳酸熔融缩聚,制备了粘均相对分子质量较低的聚乳酸,并以亚磷酸三苯酯和1,4-丁二醇二缩水甘油醚为扩链剂对其扩链。亚磷酸三苯酯和1,4-丁二醇二缩水甘油醚可以有效提高聚乳酸的粘均相对分子质量,但是,扩链产物PLLA-TPPi和PLLA-BDDE的粘均相对分子质量未随亚磷酸三苯酯和1,4-丁二醇二缩水甘油醚的用量呈线性变化,而是表现为一峰值。PLLA-TPPi和PLLA-BDDE的玻璃化温度均随扩链产物的粘均相对分子质量的增大而提高;与PLLA-BDDE相比,PLLA-TPPi链中的TPPi结构更能有效促进PLLA链的结晶。

Poly（L-lactic acid） with low viscosity average molecular weight prepared by melt polycondensation of L-lactic acid was extended by triphenyl phosphate and 1,4-butanediol diglycidyl ether, respectively. Triphenyl phosphate and 1,4- butanediol diglycidyl ether were effectively chain extender, which was confirmed by the results that viscosity average molecular weight was promoted obviously after chain extension of PLLA. However, viscosity average molecular weight of PLLA-TPPi and PLLA-BDDE did not change with the content of TPPi or the content of BDDE, but exhibited a peak value. T~ of PLLA-TPPi and PLLA-BDDE increased with the increasing of viscosity average molecular weight. Compared with PLLA-BDDE, the structure of TPPi in PLLA-TPPi chain was more effective to promote the crystallization of PLLA.