STUDIES ON THE NATURE OF THE MACROMOLECULAR CONDENSED STATE OF "NASCENT" ULTRA HIGH MOLAR MASS POLYETHYLENE  

作　　者：Zhong-yong Fan Qiang Lan Hai-shan Bu Li-heng Wu Lin Sun Ren-yuan Qian Shou-xi Chen Yong-feng Men Bing-zheng Jiang 

机构地区：[1]Department of Materials Science,Fudan University,Shanghai 200433 [2]China Textile 4cademy,PO Box 651,Beijing 100025 [3]Institute of Chemistry,Chinese Academy of Sciences,Beijing 100080 [4]Changchun Institute of Applied Chemistry,Chinese Academy of Sciences,Changchun 130022 [5]Faculty of Physics,University of Freiburg

出　　处：《Chinese Journal of Polymer Science》2001年第1期25-31,共7页高分子科学(英文版)

基　　金：This work was supported by the National Key Projects for Fundamental Research-“Macromoleular Condensed State”,Ministry of Science and Technology,China

摘　　要：Ultra high molar mass polyethylene(UHPE)powder as polymerized in a slurry process has been studied,in its nascent state,after recrystallization on rapid cooling from the melt and after hot compression molding to a film,by DSC,effect of annealing the recrystallized specimen at 120 similar to 130 degreesC,morphology by polarizing optical microscopy and small angle X-ray scattering.Based on the experimental results obtained the macromolecular condensed state of the nascent UHPE powder is a rare case of a multi-chain condensed state of non-interpenetrating chains,involving interlaced extended chain crystalline layers and relaxed parallel chain amorphous layers.On melting,a nematic rubbery state of nanometer size domain resulted.The nematic-isotropic transition temperature was judged from literature data to be at least 220 degreesC,possibly higher than 300 ℃,the exact temperature is however not sue because of chain degradation at such high temperatures.The recrystallization process from the melt is a crystallization from a nematic rubbery state.The drop of remelting peak temperature by 10 K of the specimen recrystallized from its melt as compared to the nascent state has its origin in the decrease both of the crystalline chain stem length and of the degree of crystallinity.The remelting peak temperature could be returned close to that of the nascent state by annealing at 120~130 ℃.

关 键 词：ultra high molar mass polyethylene RECRYSTALLIZATION REMELTING annealing nematic state 

分 类 号：O63[理学—高分子化学]