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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。
L-lactic acid melt polycondensation was used to prepare polylactic acid with lower viscosity average molecular weight and its chain extension with triphenyl phosphite and 1,4-butanediol diglycidyl ether as chain extenders. Triphenyl phosphite and 1,4-butanediol diglycidyl ether can effectively improve the viscosity-average molecular weight of polylactic acid, however, the viscosity-average molecular weight of the chain extended products PLLA-TPPi and PLLA-BDDE are not the same with that of The amount of triphenyl phosphate and 1,4-butanediol diglycidyl ether changed linearly, but showed a peak value. The glass transition temperatures of PLLA-TPPi and PLLA-BDDE both increase with the increase of viscosity-average relative molecular mass of the chain extended product. Compared with PLLA-BDDE, the structure of TPPi in PLLA-TPPi chain is more effective in promoting PLLA chain crystallization.