【摘要】 研究了常压下微波辐射开环聚合制备聚D,L-丙交酯(PDLLA)。考察了单体纯度、微波辐射时间、催化剂用量和体系真空度对聚合反应的影响。采用气相色谱(GC)测定丙交酯纯度;FTIR和1H-NMR表征产物结构;GPC测定分子量分布。实验结果表明:重结晶4次后的丙交酯,在催化剂辛酸亚锡用量为0.15%,常压下经微波辐射30min,可获得分子量为21.87×104的PDLLA。反应时间与传统法相比大大缩短。与传统合成法的不同还表现为,随丙交酯纯度的提高,最佳聚合时间延长;体系真空度对反应无影响。GPC结果表明聚合产物的分子量分布较窄。更多还原

【Abstract】 Poly(D,L-lactide) was synthesized by microwave-irradiated ring-opening polymerization catalyzed by stannous octoate under atmospheric pressure. The effects of monomer purity, catalyst concentration, microwave irradiating time and vacuum level on the polymerization were studied. The lactide purity was determined by the gas phase chromatograph(GC), the structure of polymer was characterized by FTIR and 1H-NMR and the molecular weight distribution index(Mw/Mn) was determined by GPC. Polylactide with viscosity average molecular weight of 21.87×104 was obtained by using 450W microwave irradiation for 30min in the presence of 0.15% catalyst under atmospheric pressure. Different from the conventional heating mothod, the optimal microwave irradiation time prolongs with the increasing of lactide purity and the vacuum level has no influence on polymerization. The polymerization rate is much faster than that of the conventional. Moreover, the results of GPC indicate that the molecular weight distribution of the polymer obtained is satisfactory.更多还原