SnCl_(2)·2H_(2)O催化乳酸熔融缩聚制备聚乳酸

Preparation of Polylactic Acid by SnCl_(2)·2H_(2)O Catalyzed by Melt Polycondensation of Lactic Acid

以氯化亚锡二水化合物(SnCl_(2)·2H_(2)O)作为催化剂,采用直接熔融缩聚法制备聚乳酸,研究了反应装置、催化剂活性、反应温度、反应时间等工艺条件对聚乳酸分子量和产率的影响,并通过傅里叶红外光谱(FTIR)和核磁共振(NMR)确定产物分子结构。结果表明,以Schlenk反应瓶作为反应装置制备的产物为聚乳酸,制备的最优反应条件为:反应温度165℃,反应时间24 h,催化剂的质量分数为0.4%,投料方式为一次性投入。由分子量和产率测试结果得出Schlenk反应瓶的特殊结构有效减少了丙交酯的损失,提高了产物的分子量和产率,所制备出的聚乳酸分子量最高可达3.7万。

The influence of reaction equipment,catalyst activity,reaction temperature,reaction time and other process conditions on the molecular weight and yield of polylactic acid which prepared by direct melt polycondensation method by using SnCl_(2)·2H_(2)O as catalyst were studied.The molecular structure of the product was determined by Fourier transform infrared spectrometer(FTIR)and nuclear magnetic resonance spectrometer(NMR).The results show that the product prepared by the Schlenk reaction flask is polylactic acid.The optimal reaction condition is that the reaction temperature is 165℃,the reaction time is_(2)4 h,and the catalyst content is 0.4%.The feeding method is one time input.The testing results of molecular weight and yield of the product could show that the special structure of Schlenk reaction flask could reduce the loss of lactide and improve the molecular weight and yields of products.The molecular weight of the prepared polylactic acid could achieve 37000 g/mol.