有机锡化合物引发D,L-丙交酯的开环聚合

D,L-丙交酯在有机锡化合物四苯基锡(Ph4Sn)、三正丁基醋酸锡(Bu3SnOAc)、辛酸亚锡(SnOct2)等催化剂引发下开环聚合,得到高分子量的聚D,L-乳酸,讨论了聚合单体D,L-丙交酯纯度、聚合温度、聚合时间、聚合体系真空度以及引发剂有机锡催化剂与聚合单体D,L-丙交酯的比例对聚D,L-乳酸合成的影响,通过红外光谱和核磁共振光谱对聚D,L-乳酸的结构进行了表征。实验结果表明,D,L-丙交酯开环聚合反应的较佳工艺路线是:D,L-丙交酯重结晶5次,聚合温度140℃,聚合时间24 h,聚合体系真空度13.3~133.3 Pa,引发剂有机锡催化剂与单体D,L-丙交酯比例0.2‰~0.5‰,此时聚D,L-乳酸的粘均分子量最高,分别达到32.46×104,33.43×104和41.36×104。

Ring-opening polymerization of D,L-lactide initiated by organictin compounds

Using organic tin compounds,such as tetraphenyltin, tributyltin acetate and stannous octoate as initiators,poly(D,L-lactide) was synthesized by ring-opening polymerization of D,L-lactide.The effects of reaction conditions,such as purity of monomer,polymerization temperature,polymerization time,vacuum level and ratio of initiator to monomer on molecular weight of poly(D,L-lactide) were discussed.The poly(D,L-lactide) was also characterized by IR and 1H NMR.The experimental results showed that the excellent technical conditions are as following:five times recrystallization of D,L-lactide,polymerization temperature 140 ℃,polymerization time 24 h,vacuum level 13.3～133.3 Pa,the ratio of catalyst to monomer 0.2‰～0.5‰,so the viscometric average molecular weight of poly(D,L-lactide)are separately 32.46×104,33.43×104 and 41.36×104.