摘要:
以辛酸亚锡为引发剂开环聚合制备了聚己内酯(PCL),用GPC、DSC、XRD和FT-IR进行表征。将PCL与N990用炭黑以溶剂法复合制备了PTC复合材料,研究其微观结构、体积膨胀和电性能。结果表明:PCL的数均分子量(Mn)、重均分子量(Mw)以及分子量分布宽度(Mn/Mw)分别为24175、38666和1.60,熔点为62℃,结晶度为42.48%。复合材料的渗流阈值为35%,PTC强度都大于2个数量级。N990炭黑在复合材料中分布较均匀,主要以聚集体的形式存在。复合材料的电阻率对数值-体积膨胀率曲线表明,体积膨胀只是复合材料PTC效应的一个重要因素。
Abstract:
Poly-ε-caprolactone(PCLs)was synthesized by ring-opening polymerization of ε-caprolactone initiated by caprylate stannous and was characterized with GPC,DSC,XRD and FT-IR respectively.PTC composite was prepared from mixing carbon black N990 and PCL and their microstructure,volume expansion and electrical properties were investigated.The results show that the number-average molecular weight(Mn),weight-average molecular weight(Mw)and polydispersity index(Mw/Mn)of PCL are 24175,38666 and 1.60.Its melting point is 62℃ and degree of crystallization is 42.48%.The percolation threshold of the PCL composites is 35%by weight and the PTC intensity are higher than two orders of magnitude.Carbon particles are dispersed uniformly in PCL matrix,mainly in form of aggregates.Curves of the logarithm of resistivity versus volume of N990/PCL composites indicate that volume expansion is only one of important factors of PTC effect.
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