熔融缩聚法直接合成聚L-乳酸的研究

Direct synthesis of poly(L-lactic acid) by melt polycondensation

以L-乳酸为原料,熔融缩聚法直接合成聚L-乳酸。考察了预聚工艺、催化剂配比及用量、反应温度、反应时间及真空度等条件对乳酸聚合反应的影响。通过红外光谱(FTIR)和核磁共振波谱(1H-NMR)分析和表征聚乳酸的结构,凝胶渗透色谱(GPC)测试其分子量及分子量分布。研究表明,较为适宜的工艺条件为:以二水合氯化亚锡(SnCl2.2H2O)和对甲基苯磺酸(TSA)为催化剂,且SnCl2.2H2O相对于乳酸预聚体的质量比为0.5%,真空度-0.98MPa,温度180℃,反应时间10h。得到的聚L-乳酸的粘均分子量为6.17×104,分子量分布1.37,且产率较高,色泽较浅。

The melt polycondensation of L-lactic acid was studied. The effects of oligomerization conditions, catalyst, temperature, time, and system vaccum were discussed. The structure of PLLA was analyzed by FTIR and ^1 H NMR, and the molecular weight was tested by GPC. The study indicated that, with SnCl2 . 2H2O and TSA as the catalyst, the comparatively appropriate reaction conditions were as follows： the catalyst content was 0. 5 ＆ to OLLA, polymerized at 180℃ for 10h under a system vacuum of -0.98MPa. As a result, the viscosity average molecular weight was 6.17× 10^4 , with a narrow molecular-weight distribution, high production rate and light color.