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采用低毒锌类催化剂制备了一系列具有高分子量、不同光学纯度及热力学性质的聚乳酸材料.以金属锌作催化剂制备丙交酯,研究了不同裂解温度对产物光学纯度的影响.随后在低毒催化剂乳酸锌的作用下使丙交酯开环聚合,进一步研究了单体的光学纯度对聚乳酸立体规整性的影响,以及聚合过程中的结晶对聚合物分子量和热力学行为的影响.并用旋光仪、核磁共振氢谱(1HNMR)、凝胶渗透色谱(GPC)、差示扫描量热分析(DSC)等方法对产物进行表征.结果表明,合适的裂解温度有利于合成高光学纯度的丙交酯;在低毒乳酸锌的催化作用下,高光学纯度的单体以及聚合过程中的结晶都有利于制备高分子量聚乳酸.
A series of polylactic acid materials with high molecular weight, different optical purity and thermodynamic properties were prepared by using low-toxic zinc catalyst.The effects of different pyrolysis temperature on the optical purity of the product were studied by using zinc metal as catalyst to prepare lactide, The effect of the monomer purity on the stereoregularity of polylactic acid and the effect of the crystallization during the polymerization process on the molecular weight and thermodynamic behavior of the polymer were studied by ring opening polymerization of lactide under the action of zinc catalyst. The products were characterized by 1HNMR, GPC and DSC.The results showed that the suitable pyrolysis temperature was favorable for the synthesis of high optical purity Ester; under the catalysis of low toxic zinc lactate, high optical purity monomers and the crystallization during the polymerization are conducive to the preparation of high molecular weight polylactic acid.