点击次数：

发布时间：2019-03-09

论文类型：期刊论文

发表时间：2012-04-01

发表刊物：POLYMER BULLETIN

收录刊物：Scopus、EI、SCIE

卷号：68

期号：7

页面范围：1789-1799

ISSN号：0170-0839

关键字：Hafnium; Isoselectivity; Lactide; Polymerization; Zirconium

摘要：The hydroxyl- and phenoxy-bridged dinuclear zirconium and hafnium complexes, 1 and 2, containing a chiral N atom in the N2O2 ligand (H2L = 2-(((2-pyridylmethyl)(2-hydroxyphenyl)amino)methyl)-4,6-di(tert-butyl)phenol) were used as catalysts for the ring-opening polymerization of rac-lactide. Experiments prove that 1 and 2 are living and controlled catalytic systems with activity up to 3.25 g(pol) mmol(ini) (-1) h(-1). The isotactic-rich polylactides in a narrow polydispersity (M (w)/M (n) = 1.01-1.13) were produced with enantiomeric complexes 1 and 2 (P (m) = 0.65-0.73). The kinetic studies show a first-order dependency in both monomer and initiator. The initiation mechanism is discussed on the basis of the MALDI-TOF MS and H-1 NMR spectra of the rac-LA oligomer prepared by 1.