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茂金属聚乙烯的支化非均匀性与结晶形态
引用本文:傅强,杜荣昵,邱方遒,何天白.茂金属聚乙烯的支化非均匀性与结晶形态[J].高分子学报,2000,36(2):142-146.
作者姓名:傅强  杜荣昵  邱方遒  何天白
作者单位:四川联合大学高分子材料与工程系!成都610065(傅强,杜荣昵),长庚大学化工系!桃园(邱方遒),高分子物理开放实验室中国科学院长春应用化学研究所!长春130022(何天白)
基金项目:国家自然科学基金!(基金号 2 970 40 0 7),长春应用化学所高分子物理开放实验室资助
摘    要:以美国Exxon公司生产的茂金属短支链聚乙烯 (SCBPE)为研究对象 ,用DSC热分级方法研究了不同支链含量聚乙烯的支化非均匀性 ,并用TEM表征茂金属聚乙烯在不同条件下熔体结晶的形态 .SCBPE经逐步结晶分级后 ,其DSC熔融曲线出现多峰 ,表明茂金属SCBPE仍具有很大的非均匀性 .支链含量愈高 ,熔点愈低 ,非均匀性增加 .SCBPE的晶体形态随平均支链含量的增加片晶厚度减小 ,片晶尺寸分布增加 ;含量较低时 ,SCBPE在不同温度下均生成球晶结构 .随结晶温度的降低支链含量较多的分子也能参与结晶 ,故生成的片晶厚度减小 .从相分离的熔体中结晶 ,大尺度的片晶集聚体间的分离和小尺度的片晶之间相分离同时存在 .

关 键 词:热分级  结晶形态  茂金属短支链聚乙烯
修稿时间:1998-10-13

MOLECULAR HETEROGENEITY AND CRYSTAL MORPHOLOGY IN METALLOCENE SHORT CHAIN BRANCH POLYETHYLENE (SCBPE)
FU Qiang,DU Rongni.MOLECULAR HETEROGENEITY AND CRYSTAL MORPHOLOGY IN METALLOCENE SHORT CHAIN BRANCH POLYETHYLENE (SCBPE)[J].Acta Polymerica Sinica,2000,36(2):142-146.
Authors:FU Qiang  DU Rongni
Abstract:Metallocene, a newer generation of commercial polymerization catalysts for polyolefins, is best known for its “single sitednss”, and the intermolecular structural homogeneity of metallocene polyethylene copolymer is a very interesting research issue. The molecular segregation effects on the crystallization, melting and crystal morphologies of metallocene SCBPE have been investigated with DSC and TEM.The multiple endothermic peaks were observed in the DSC thermograms during heating experiments. The heterogeneity increases as branching content increases, the lamellae becomes thinner, and lamellae distribution becomes broader. Both macroscopic segregation (between two crystal aggregates) and microscopic segreation (between two lamellae) have been observed when SCBPE crystallized from phase separated melt.
Keywords:Thermal segregation  Crystal morphology  SCBPE  
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