【摘要】 以D,L-乳酸为原料,氯化亚锡(SnC l2)与萘二磺酸(NDA)为催化剂体系,熔融缩聚制备聚乳酸,并采用旋光度法1、H-NMR和13C-NMR核磁共振法、X-射线衍射和黏度法等研究萘二磺酸对聚乳酸微结构的影响。SnC l2和NDA分别催化D,L-乳酸聚合可制备消旋的非晶态聚乳酸,而SnC l2/NDA催化体系所得的聚乳酸是高光学活性的L-构型的结晶聚合物。SnC l2/NDA催化体系具有高度的立构选择性,且SnC l2与NDA配比及其用量对聚乳酸的光学活性、分子链的构型、链段序列分布和晶体结构等微结构均有明显的影响。当SnC l2质量分数为0.5%、n(SnC l2)/n(NDA)为1∶1时,D,L-乳酸熔融缩聚可制备光学纯度97.4%的高光学活性的L-型聚乳酸。更多还原

【Abstract】 Polys(lactic acid) was prepared from D,L-lactic acid through melt polycondesation.Viscometry,polarimetry,1H-NMR,13C-NMR and XRD were performed to detect poly(lactic acid)(PLA) samples.PLA with excessive L-onformation units in polymer chains can be obtained using SnCl2 and naphthalene disulphonic acid(NDA) as catalyst system.Ratios of SnCl2 and NDA and its contents affected the opitical purities of PLAs,PLA microstructures of chains and cryticals.When SnCl2 content was 0.5% and n(SnCl2)/n(NDA) 1∶1,PLA with opitical purity 97.4% was then obtained from D,L-lactic acid.更多还原