高密度聚乙烯导电复合材料介电性能的研究

用熔融共混和热压工艺制备了CB/HDPE,MWNT/HDPE聚合物基复合材料,研究了填料体积含量,测试电压,填料形貌尺寸对复合体系介电性能的影响.实验表明,当导电填料含量达到渗流阈值附近时复合材料的介电常数达到最大,测试电压达到一定值时,渗流阈值附近的复合材料介电损耗会迅速增加,相同填料体积含量的MWNT/HDPE复合体系比CB/HDPE体系具有更高的介电常数,利用渗流理论、Maxwell-Wagner界面极化效应和微电容模型解释了实验现象.

Dielectric Properties of High Density Polyethylene Conductive Composites

Polymer composites CB/HDPE,MWNT/HDPE,were prepared by a blending and hot-compressing technique.Effects of filler volume fraction,test voltage,shape and size of the filler on dielectric properties of the composite were studied.The experiment shows that when the content of conductive filler reaches the percolation threshold,dielectric constant of the composite reaches the largest;when the voltage is constant,dielectric loss of the composite which is around the percolation threshold will increase quickly.The composite MWNT/HDPE has higher dielectric constant than CB/HDPE under the same filler volume.The percolator theory,Maxwell-Wagner interface polarization effect and the micro capacitor model can be used to explain these experimental results.