碳纳米管聚合物复合材料导电性能研究

Study on Conductive Properties of Carbon Nanotubes Polymer Composites

提出了聚合物基碳纳米管的交叠接触模型。深入探讨了碳纳米管和聚合物两种组分材料各自的电导率与质量分数、碳纳米管的几何参数和碳纳米管连接处聚合物基质填缝小区域中的电子隧道效应等因素对碳纳米管聚合物复合材料导电性能的影响,导出了碳纳米管聚合物复合材料的电导率公式。数值计算了不同条件下多壁碳纳米管苯氧基复合材料和多壁碳纳米管聚苯醚砜复合材料的电导率对数。模拟结果表明:适当增加碳纳米管的质量分数能显著改善复合材料的导电性能;增大碳纳米管的弯曲度会导致材料的导电性能明显减弱;对于每一种碳纳米管聚合物复合材料,碳纳米管质量分数存在一个临界值,超过临界值时,随着碳纳米管质量分数增加,电导率的增加逐渐变缓,并最终趋于一个定值,即在复合物中形成了比较稳定的导电网络。理论值与已获得的实验数据相吻合。

The overlapping contact configuration model of carbon nanotubes in polymer matrix is proposed. The effects of conductivity and mass fraction of carbon nanotubes as well as polymer,geometric parameters of carbon nanotubes,and the electrical tunneling effect due to a small region of the polymer matrix material filling the gap at the nanotubes junction on the conductive properties of carbon nanotubes polymer composites are discussed in detail. The conductivity formula of the composites is deduced. The conductivity logarithms of multiwalled carbon nanotubes phenoxy compositie and multiwalled carbon nanotubes polyethersulfone composite are calculated numerically under different conditions. The simulate results show that the appropriate increase of the carbon nanotubes mass fraction can obviously improve the conductive properties of the composites. The conductivity of the material decreases remarkably as the curvature degree of carbon nanotubes increases. There is a critical value of nanotubes mass fraction for each carbon nanotubes polymer composites. When nanotubes mass fraction is larger than the critical value,the conductivity of the composite would increase slowly with the mass fraction increasing,and the conductivity would finally tend to a constant,namely there is a stable electrical network structure in the composite. The theoretical results are in good agreement with the available experimental data.