齐民
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论文类型:期刊论文
发表时间:2022-07-03
发表刊物:高分子材料科学与工程
所属单位:化工学院
卷号:23
期号:3
页面范围:92
ISSN号:1000-7555
摘要:The kinetics of(R,S) beta-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 beta-butyrolactone
polymerization using distannoxane were first order in monomer
concentration and 0.56 order in initiator
concentration,respectively.~(13)C-NMR spectra analysis of stereochemical
sequence distributions at various polymerization temperatures for the
distannoxane showed activation energy(DeltaE=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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