【摘要】 将不同长径比碳纳米管填充PVDF复合材料进行等温热处理,实时监测电阻率随时间的变化,研究了碳纳米管在PVDF熔体中导电网络形成的动力学过程。结果表明,电阻率-时间曲线在达到某一临界时间时电阻率迅速下降,随着热处理温度的升高和MWNTs含量的增加,渗流时间减小。渗流时间与温度的Arrhenius关系曲线表明,碳纳米管长径比对其导电网络形成具有重大影响。提出了一个修正的热力学渗流模型预测碳纳米管填充PVDF体系的渗流时间。更多还原

【Abstract】 The kinetics of conductive network formation in PVDF/MWNTs and PVDF/s-MWNTs systems were investigated by in-situ tracing the time dependence of electrical resistivity when the samples were isothermally treated above the melt point of PVDF. It is observed that the electrical resistivity-time curves show a certain self-similarity, i.e., the electrical resistivity decreases sharply when a critical time (tp) is reached. The dynamic percolation curves for above systems shift to a shorter critical time with increase of either the annealing temperature or the filler concentration. The activation energy of the conductive network formation, which is calculated by the Arrhenius plots of tp against the annealing temperature, suggests that the aspect ratio of MWNTs has remarkable effect on the conductive network formation. A modified thermodynamic percolation model is proposed to predict the tp for the composites, and the predicted data fit the experimental results very well.更多还原