炭黑结构度对HDPE/CB导电复合材料导电网络形成与破坏的影响

采用熔融混合方法制备高密度聚乙烯/炭黑(HDPE/CB)导电复合材料,比较不同结构度CB填充体系的逾渗曲线和温度-电阻行为,并研究了不同含量、不同结构度CB填充的HDPE的结晶行为。实验结果表明,高结构度CB可使填充体系逾渗值显著下降(本研究中可降低为2.7%);低结构度CB填充体系的正温度系数(PTC)效应强度比高结构度CB填充体系高出约3;降温过程中,温度-电阻率曲线上出现电阻突变峰的强度随着CB结构度的降低而增强;差示扫描量热(DSC)和广角X射线衍射(WAXD)结果显示,CB粒子的加入对HDPE的结晶行为没有显著影响。

The Effect of Carbon Black Structure on the Room Temperature-Resistivity of HDPE/CB Composites

Composite materials based on high-density polyethylene(HDPE) and different kinds of carbon black(CB) were prepared by melt processing.The room temperature resistivity and the behavior of resistivity of composites during heating and cooling cycles were studied.Composites filled with low structure CB reveal higher conductive percolation threshold.During the heating cycle,the HDPE/CB composites with VXC-68 as the conductive filler show the highest PTC intensity.A cooling-induced resistivity increase and decrease was observed during cooling below 118 ℃.The crystallization behaviors of the conductive composites also have been studied by differential scanning calorimetry(DSC) and wide angle X-ray diffraction(WAXD).It is the fact that crystal structure of polymer matrix is hardly impacted by CB,further proofs that the difference of CB structure affects temperature-resistivity behavior during melting and crystallizing of matrix.