碳纳米管/炭黑混杂填充聚甲醛复合材料导电性能研究

ELECTRICAL PROPERTIES OF MULTIWALLED CARBON NANOTUBE/CARBON BLACK HYBRID FILLER FILLED POLYOXYMETHYLENE COMPOSITES

采用在转矩流变仪中熔融混合的方法制备了多壁碳纳米管(MWCNTs)和导电炭黑(CB)共同填充的聚甲醛(POM)导电复合材料,研究了材料的体积电阻率和导电填料用量之间的关系.用该体系的实验数据点对已发表的混合导电填料体系的定量关系式进行了验证,结果表明实验数据点和理论预测略有偏差.为方便实际应用,把混合导电填料体系的定量关系式加以发展,推导出逾渗值和两种导电填料质量比之间的关系式,并绘出了工作曲线.设计实验对工作曲线进行了验证,结果表明工作曲线对实践具有指导意义.

Multiwalled carbon nanotubes（MWCNTs）/carbon black（CB） mixed filler filled polyoxymethylene（POM） composites were prepared by melt mixing in a rotational rheometer.The relationship between electrical resistivity of the composites and the filler concentration was investigated.The electrical percolation threshold of MWCNTs/CB mixed filler-filled POM is much lower than that of CB-filled POM but higher than MWCNTs-filled POM,because MWCNTs and CB build up the conductive path together.The experimental data were used to examine the existing equation derived from the model of mixed filler systems which was published previously,and the comparison showed that deviation existed for some data points.It is speculated that the conditions for using the model are too ideal,not suitable to practical cases,so deviation is inevitable.In order to facilitate the practical application,the equation was further developed,and a new equation describing the relationship between percolation threshold and the ratio of the two fillers was obtained.A working curve was drawn on the basis of the newly developed equation and examined by the experimented data.The results demonstrate that the working curve can provide a general guidance for practice.This work shows that the existing model of mixed carbon filler systems is useful for predicting the conductive behavior of the composite materials.