低逾渗MWCNTs-CB/UHMWPE导电复合材料的制备及性能

Preparation and Properties of MWCNTs-CB/UHMWPE of Low Percolation Conductive Composites

采用溶液法及机械共混法分别制备了均匀结构的炭黑(CB)/超高分子量聚乙烯(UHMWPE)及隔离结构的多壁碳纳米管(MWCNTs)-CB/UHMWPE复合薄膜。扫描电镜分析显示,虽然大部分CB均匀分散于UHMWPE基体中,但依然存在明显的局部团聚,而隔离结构中的MWCNTs-CB分布于UHMWPE界面间,更易形成导电通道。导电测试结果表明,复合材料的导电逾渗值由均匀分布的4.91%(体积分数)下降到隔离结构的0.42%。MWCNTs的加入完善了CB间的导电网络,使复合材料的逾渗值进一步下降,当CB∶MWCNTs=15∶1时,复合薄膜的逾渗值由0.42%(体积分数)下降到0.24%,然而混合填料中MWCNTs含量的进一步增加几乎对逾渗值没有影响。力学性能研究表明,隔离型复合材料的拉伸强度和断裂伸长率随填充剂含量的增加呈现出先上升后下降的趋势。

Carbon black（CB）/ultrahigh molecular weight polyethylene（UHMWPE）with uniform structure,and multi-walled carbon nanotubes（MWCNTs）-CB/UHMWPE composite film with segregated structure were prepared by solution method and mechanical blending,respectively.Scanning electron microscopy（SEM）results for composites fractured surface show that although most of CB are homogeneously dispersed in the UHMWPE matrix,but there is still significant local agglomeration,and the MWCNTs-CB in segregated structure are located at the UHMWPE interface.Compared to uniformed CB/UHMWPE composites,the conductive percolation threshold of segregated CB/UHMWPE composites is decreased from 4.91%to 0.42%,due to the clustered distribution of filler in the interface between UHMWPE particles,which is easier to form a conductive path.Adding a small amount of MWCNTs in composite materials can form more complete conductive network and make percolation value significantly decrease.As only CB∶MWCNTs is 15∶1,the percolation threshold of CB/UHMWPE composites with segregated structure can decrease from 0.42% to 0.24%.Meanwhile,it does not has a significantly influence on percolation threshold with the increase of MWCNTs content.The mechanical properties of the composites first increase and then decrease with increasing of fillers content.