二水合氯化亚锡催化制备高分子量聚乙交酯

Achieving high molecular weight polyglycolide using stannous Chloride Dihydratecatalyst

二水合氯化亚锡(SnCl_(2)·2H_(2)O)/月桂醇(DA)可控催化乙交酯(GL)本体开环聚合制备了高分子量聚乙交酯(PGA)。研究了反应温度、反应时间、催化剂用量、单体-引发剂配比和单体及催化剂纯度对所得PGA的特性粘度和色泽的影响。优化聚合反应条件下,以SnCl_(2)·2H_(2)O为催化剂,羟基引发剂作为聚合物分子量调节剂,催化剂用量为100 ppm,在180℃下反应3 h,调控聚合得到特性粘度达4.09 dL/g的PGA。通过比较PGA的色泽,发现样品随反应条件变化发生不同程度的褐变,其褐变可能与温度过高和传热不良有关;并观察到调控聚合反应速率可以控制PGA的色泽,优化反应条件下可获得白色的PGA。

High molecular weight polyglycolide(PGA)was synthesized via varying reaction conditions of bulk ring-opening polymerization(ROP)of glycolide catalyzed by stannous chloride dihydrate/lauryl alcohol(SnCl_(2)·2H_(2)O/DA).The effects of polymerization temperature,polymerization duration,catalyst usage,the ratio of monomer to initiator as well as the purity of the monomer and the SnCl2·2H2O catalyst on the intrinsic viscosity and the color of the polymer products were investigated.A set of optimized polymerization conditions were identified which resulted in the formation of PGA products with intrinsic viscosity as high as 4.09 dL/g:100 ppm of SnCl_(2)·2H_(2)O as catalyst,180℃for 3 h,and a hydroxyl compound initiator for regulating molecular weight.From comparison of the colors of various PGA products from the study,it was noted that color darkening was associated with polymerization conditions.The color darkening was probably influenced by overheating and inadequate heat transfer.It was also observed that the color of the PGA products can be improved via changing the reaction rate.Under the optimal reaction conditions,a product of white color can be obtained.