含半不稳定边臂配体的钛配合物催化丙交酯聚合  

Ring-opening Polymerization of Lactide Catalyzed by Titanium Complexes with Schiff Base Ligand Bearing a Hemilabile Side Arm

作　　者：诸婷婷[1] 谢明明[1] 龚狄荣[1] ZHU Tingting XIE Mingming GONG Dirong(Department of Materials Science and Chemical Engineering, Ningbo University, Ningbo 315211)

机构地区：[1]宁波大学材料科学与化学工程学院,宁波315211

出　　处：《材料导报》2017年第14期40-45,共6页Materials Reports

基　　金：浙江省自然科学基金(LY17E030002);宁波市自然科学基金(2016A610045);国家自然科学基金(21304050)

摘　　要：聚乳酸类材料作为可生物降解性材料具有广阔的应用前景。设计、合成了6种含半不稳定边臂的希夫碱配体L1—L6,并与钛酸四异丙酯络合合成相应的6种配合物C1—C6,配合物的结构和化学组成经元素分析、红外测试确定。将其作为催化剂催化丙交酯开环聚合,以催化剂C1为考察对象,系统研究了催化剂用量、温度、时间对聚合反应的影响,发现当单体与催化剂配比为2 000,温度为160℃,反应24h时,聚合产率最高,达90.35%,聚合物分子量达8.41×104。在上述优化条件下,比较了催化剂C1—C6的活性,结果表明催化剂活性按以下顺序递减:C6>C4>C3>C1>C2>C5,同时,催化剂中心金属钛原子周围位阻相对稍小,配体中含配位能力较弱的半不稳定O边臂均有利于提高催化剂的活性。Polylactic acid is an important biodegradable material which has diversified applications in our daily life.We designed and synthesized six Schiff base ligands with hemilabile side arm oxygen or sulfide（L1—L6）and their corresponding complexes（C1—C6）by the reaction with tetraisopropyl titanate.The structures of the complexes were identified by elemental analysis and infrared spectroscopy.The catalytic performance in lactide ring-opening polymerization were carefully examined.Different polymerization conditions such as catalyst concentration,temperature,polymerization time as well as the catalyst structures were investigated in order to study their influences on the polymerization behaviors towards lactide with C1 as a typical example.We found the polymer yield reached the highest level of 90.35% and the molecular weight of the polymer reached8.41×10^4 g/mol at molar ratio of monomer to catalyst of 2 000 at 160℃for 24 h.The catalyst activity decreased in the order of C6〉C4〉C3〉C1〉C2〉C5 at the optimal conditions.The less bulkiness of catalyst environment around the metal center and the hemilability of the side arm which has weaker coordination ability and are both beneficial to improve the activity.

关 键 词：聚乳酸 丙交酯 催化剂 开环聚合 含半不稳定边臂的希夫碱配体 钛配合物 

分 类 号：O643.321[理学—物理化学]