填充型导电复合材料载荷作用下导电逾渗研究

Research on Conductive Percolation of Filled Conductive Composite Material under Loading

以聚丙烯(PP)为基体材料,以多壁碳纳米管(MWCNT)、导电炭黑(CB)为填料,通过熔融共混、注塑成型的方法制备了填充型导电复合材料。测定在单轴压缩载荷作用下,不同填料体系的导电复合材料逾渗曲线的变化规律。通过扫描电子显微镜观察了导电填料的分布以及导电网络的形成状况。结果表明:对于PP/CB和PP/CB/MWCNT导电复合材料,在较小的应变情况下,单轴压缩使逾渗曲线向低阻方向移动,而随着应变逐渐增大,逾渗曲线又向高阻方向移动,其中PP/CB体系更为明显。这是由于纤维状的MWCNT能部分抑制由于压缩而导致材料内部导电通路的破坏,使材料内部导电网络遭到破坏的程度降低,同时,CB通过与拥有大长径比的MWCNT的协同作用提高了复合材料的导电性。

The filled conductive composite material was prepared with polypropylene (PP)as matrix material,multiwalled carbon nanotubes (MWCNTs)and conductive carbon black (CB)as fillers by the methods of melt blending and injection molding.Percolation curves of the composites material with different filler system could be measured under uniaxial compression loading.And the distribution of conductive filler and the formation of conductive network were investigated by scanning electron microscope.The results show that the percolation curves of PP/CB and PP/CB/MWCNTs conductive composite material system move to the direction of low resistance with uniaxial compression under small strain.When the strain increases gradually, the percolation curves move to the high resistance direction.The moving of percolation curves of PP/CB composites have been more obvious than PP/CB/MWCNTs composites.Because the MWCNTs of fibrous could partly inhibit the destruction of conductive path inside the material which is caused by compressive load, and reduces the extent of the destruction to the internal conductive network.At the same time MWCNT with large length-diameter ratio in the distribution of fillers will improve the electrical conductivity of composite material with the synergy of CB.