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Date of Publication:2007-01-01

Journal:高分子材料科学与工程

Affiliation of Author(s):化工学院

Issue:3

Page Number:92-95,99

ISSN No.:1000-7555

Abstract:The kinetics of (R, S) β-butyrolactone polymerization initiated with a new distannoxane compound were investigated at various monomer/initiator ratios and reaction temperatures with dilatometer. According to the kinetics studies, chain propagation rate for β-butyrolactone polymerization using distannoxane were first order in monomer concentration and 0.56 order in initiator concentration, respectively. 13C-NMR spectra analysis of stereochemical sequence distributions at various polymerization temperatures for the distannoxane showed activation energy (ΔE=Es-Ei) of ca. -13 kJ/mol for syndiotactic versus isotactic diad formation. The triad stereosequence distributions of the synthetic P3HB agreed well with the Bernoulli model of chain end stereocontrol. Theses analyses show that distannoxane initiator produces preferentially syndiotactic polyesters (syndiotactic diad fraction from 0.6 to 0.7).

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