【摘要】 1H NMR和MALDI-TOF MS分析显示,丙交酯分别在乙醇铁和正丁醇铁合作用下开环聚合,聚合产物分子链的端基分别为相应醇铁分子的烷氧基;ICP-AES测试结果提示醇铁分子的铁原子是以共价键的形式与聚合物链相键合的。由此认为醇铁化合物是通过配位-插入机理引发丙交酯开环聚合的,链增长的过程涉及到丙交酯酰氧键的断裂并不断插入到Fe-O键中。测试聚合产物在经过1 mol/L HCl处理前后的相对分子质量变化,结果表明醇盐的3个配体都参与了引发作用。更多还原

【Abstract】 The bulk ring-opening polymerizations of D, L-lactide were carried out at 130 ℃ under the action of ferric ethoxide and ferric n-butoxide respectively. Both 1H NMR and MALDI-TOF MS analyses indicated that the end groups of the formed polymer chains were the corresponding alkyl ester end groups of the ferric alkoxieds. ICP-AES measurements revealed that the iron atoms were chemically bound to the polymer chains. It is suggested from these results that the polymerization proceeds via a coordination-insertion mechanism involving cleavage of the acyl-oxygen bond of the lactides. The changes in viscosity-average molecular mass ( Mv) of the polymerization products before and after 1 mol/L HC1 treatment showed that the lieands in Fe (OR), were converted into poly (L-lactide) (PLA) growing chains.更多还原