无催化剂直接熔融缩聚合成聚乳酸-乙醇酸

Synthesis of Poly(Lactic Acid-co-Glycolic Acid) by Direct Melt Polycondensation Without Catalysts

以乳酸（LA）、乙醇酸（GA）为原料,在无催化剂、高真空条件下直接熔融缩聚合成聚乳酸-乙醇酸（PLGA）无规共聚物,对产物进行了GPC、FTIR1、H-NMR表征,并研究了反应时间、聚合温度、LA/GA投料比对PLGA分子质量的影响.结果表明：在所研究的聚合温度范围内,PLGA分子质量随聚合时间的延长先增大后减小;聚合温度越高,PLGA所能达到的最高分子质量越小,最佳聚合温度范围为160~170℃,最佳反应时间范围为57~69 h;在相同反应条件下,LA/GA投料比越小,PLGA分子质量越大.该研究为PLGA的合成提供一种安全、经济、有效的新途径.

Poly（lactic acid-co-glycolic acid）（PLGA） was synthesized with lactic acid and glycolic acid by direct melt polycondensation without catalysts.The products were characterized by GPC,FTIR,1H-NMR.In this work,the effects of reaction time,polymerization temperature（Tp） and LA/GA feed ratio on molecular weight were investigated.Results indicated that in the range of Tp we discussed,molecular weight gradually increased and then decreased as the reaction time increased;the maximal molecular weight of PLGA decreased while Tp increased;the optimal ranges of Tp and reaction time were 160~170 ℃ and 57~69 h respectively;under the same reaction conditions,the molecular weight of PLGA increased while the LA/GA feed ratio decreased.The objective of this study is to develop an economical,safe and effective method for the synthesis of PLGA.