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机构地区:[1]上海中国纺织大学
出 处:《合成纤维工业》1996年第2期18-22,共5页China Synthetic Fiber Industry
摘 要:在290℃下经熔融共聚制得60PHB/PET热致液晶共聚酯。用毛细管流变仪测定流动性能,表明此共聚酯为切力变稀流体;其非牛顿指数、屈服应力在260℃均有突变。结合DSC,DLI,TOT等研究,共聚酯在255~258℃为PHB微晶向向列型液晶转变点。流变特征与相态有关。经高温处理(>260℃)的共聚酯熔体在较低温度下呈保持高温流动特征。而经不同温度热处理后冷却样品,其相转变热焓、相转变温度均随热处理温度的增加而增加,尤其是在260℃以上热处理后冷却样品,其相转变热焓增加较大,而280℃以上热处理后冷却样品的相转变热焓达到最大值。PHB/PET thermotropics liquid crystal copolyester is prepared by melt copolymerization at 290℃,whose flow behaviour is measured by capillary Rheometry at 250,260,280,300℃ respectively. The copolyester melt is a shearthing fluid,whose non-Newtown index,yield stress shows a transition at 260℃. The phase transition from PHB-rich phase to nematic liquid crystal at 255~258℃ has been identified by DSC,DLI,TOT,which is related to flow character. The effect of heat-treatment temperature on the flow character and phase transition of 60 PHB/PET copolyester is shown to be:The flow character of the copolymer below 250℃, which are heat-treated above 260℃,is still similar to that above 260℃. The phase transition temperature and entropy increase with the increasing of heat-treatment temperature. A clear trump is shown at 260℃.
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