非手性席夫碱-异丙氧基铝引发外消旋丙交酯的立构选择性聚合  

Stereoselective Polymerization of rac-Lactide Initiated by Achiral Schiff-base Isopropoxide Aluminum Complex

作　　者：杨永坤[1] 汤朝晖[1] 庞烜[1] 杜鸿志[1] 陈学思[1] 景遐斌[1] 

机构地区：[1]中国科学院长春应用化学研究所高分子物理和化学国家重点实验室中国科学院研究生院,长春130022

出　　处：《高等学校化学学报》2006年第2期352-355,共4页Chemical Journal of Chinese Universities

基　　金：国家自然科学基金(批准号:50273038;20274048;50373043);国家杰出青年基金(批准号:50425309)资助

摘　　要：以非手性的席夫碱-异丙氧基铝(Ⅱ)引发外消旋丙交酯(rac-LA)的立构选择性聚合.其聚合动力学研究结果表明,聚合反应对于单体符合一级反应动力学.所得聚合物的数均分子量与单体转化率成正比,并且分子量分布很窄,表明该聚合反应具有良好的可控性.此外所得的聚外消旋乳酸是tm为179℃的结晶性聚合物.13C NMR和同核去偶1H NMR谱表明,所得的聚乳酸是一种立构嵌段聚合物,平均嵌段长度为11个乳酸单元.An achiral Schiff-base isopropoxide aluminum complex（Ⅱ） was used for the stereoselective ringopening polymerization of rac-lactide. The kinetics studies indicated that rac-lactide polymerization was first order kinetics to monomer concentration. There was linear relationship between the monomer conversion and molecular weights（Mn） of the polymer with a narrow molecular distribution. These phenomena indicated that the polymerization was well controllable. Moreover, the obtained poly （rac-lactide） was crystalline polymer with relative high tm（ 179℃）. ^13C NMR and homonuclear decoupled ^1H NMR spectra revealed that the polymerization of rac-lactide initiated by complex（Ⅱ） resulted in the isotactic stereoblock polymer, which contained blocks with an average of 11 units of enantiomerically pure lactic acid.

关 键 词：非手性席夫碱-异丙氧基铝 外消旋丙交酯 立构选择性聚合 可生物降解高分子 

分 类 号：O633[理学—高分子化学]