具有隔离-双逾渗结构的PVDF/LLDPE/CB导电复合材料制备及其PTC性能  

Positive Temperature Coefficient Effect of PVDF/LLDPE/CB Conductive Composites with the Segregated and Double-Percolated Structure

作　　者：王彤彤 钟明 段咏欣[1] WANG Tongtong;ZHONG Ming;DUAN Yongxin(Key Laboratory of Rubber-Plastics,Ministry of Education,Qingdao University of Science and Technology,Qingdao 266042,China)

机构地区：[1]青岛科技大学橡塑材料与工程教育部重点实验室

出　　处：《青岛科技大学学报（自然科学版）》2019年第5期86-92,共7页Journal of Qingdao University of Science and Technology:Natural Science Edition

基　　金：中国石油科技创新基金资助项目(2017D-5007-0607);国家留学基金委青年骨干教师出国研修项目(201607890002)

摘　　要：利用聚偏氟乙烯(PVDF)和线性低密度聚乙烯(LLDPE)熔点之间的差异,以纳米级的PVDF粉体、LLDPE和导电炭黑(CB)为原料,在高于LLDPE熔融温度(120℃)但低于PVDF熔融温度(160℃)的条件下,通过简单的熔融共混成功制备了具有“隔离-双逾渗”结构的PVDF/LLDPE/CB导电复合材料。首先使用低熔点的LLDPE作为CB载体,制得LLDPE/CB母料,再利用LLDPE熔点远低于PVDF熔点的特点,将LLDPE/CB母料与PVDF粉体135℃熔融共混,在此温度下,LLDPE是熔体,而PVDF仍可保持颗粒状,从而将可流动的熔体状LLDPE/CB包裹于PVDF颗粒表面,制备了低逾渗值(质量分数2.299%)的PVDF/LLDPE/CB复合材料。所得到的复合材料具有显著的正温度系数(PTC)效应,温度上升到LLDPE熔点附近时,电阻率对温度变化敏感,升高了4个数量级,而且经过多次热循环之后,PTC重复性较好。这种复合材料可以用作温度传感器电阻,在温度过载保护领域有潜在的应用。Based on the difference between the melting point of poly(vinylidene fluoride)(PVDF)and linear low density polyethylene(LLDPE),conductive PVDF/LLDPE/CB composites with segregated and double-percolated structure were prepared by simply melted mixing.Firstly,LLDPE was used as the percolating phase and was blended with CB to get LLDPE/CB masterbatch.Then,LLDPE/CB masterbatch and PVDF were melt blended at 135℃,which is higher than the melting temperature of LLDPE and lower than that of PVDF.The surface of PVDF particles were wrapped by LLDPE/CB.Thus prepared PVDF/LLDPE/CB composites have low percolation threshold(2.299%)and obvious positive-temperature-coefficient(PTC)effect of resistivity.A fast transition from conductor to insulator was observed when the temperature was close to the melting point of LLDPE matrix,the resistivity went up by four orders of magnitude,and the composites keep good reproducibility after heating-cooling cycles.The PVDF/LLDPE/CB composites with segregated and double-percolated structure can be used as heat sensitive resistor,and have the great potential application in temperature overload protection.

关 键 词：导电复合材料 导电逾渗 正温度系数效应 隔离-双逾渗结构 

分 类 号：TQ323.41[化学工程—合成树脂塑料工业]