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研究了一系列咪唑烷基桥联双芳氧基稀土金属胺化物催化ε-己内酯开环聚合反应性能。通过对聚合物的分子量和分子量分布进行分析,结果显示,这些稀土胺化物能在相对较温和的条件下高活性引发ε-己内酯开环聚合,其催化活性随着稀土金属离子半径变大而增强,但所得聚合物的分子量分布较宽(PDI=1.21~1.89),显示它们不是可控聚合体系。加入异丙醇原位转化成稀土金属烷氧基配合物后,聚合的可控性得到了明显的改善,显示了可控聚合的特点。通过分析齐聚物的末端基,研究了这类稀土胺化物加醇体系催化ε-己内酯聚合的机制。
A series of imidazolidinyl bridged bisaryloxy rare earth metal amides were used to catalyze the ring-opening polymerization of ε-caprolactone. By analyzing the molecular weight and molecular weight distribution of the polymer, the results show that these rare earth amines can initiate the ring-opening polymerization of ε-caprolactone under relatively mild conditions and the catalytic activity increases with the radius of the rare earth metal ions But the molecular weight distribution of the obtained polymers is broad (PDI = 1.21-1.89), indicating that they are not controlled polymerization systems. Addition of isopropanol in situ into the rare earth metal alkoxide complex, the polymerization controllability has been significantly improved, showing the characteristics of controlled polymerization. By analyzing the terminal groups of oligomers, the mechanism of the polymerization of ε-caprolactone catalyzed by these rare earth amine-added alcohols was studied.