填充型聚合物基复合材料的导电和导热性能

研究了高密度聚乙烯为基体、炭黑和炭纤维为填料复合体系的导电和导热性能。发现当导电填料的含量达到渗流阈值时,复合材料的电导率急剧升高;而在渗流阈值附近,其热导率未出现突变。这表明电导渗流现象不完全是由导电粒子通过物理接触生成导电链所致。其导电机制是相当数量的导电粒子相互发生隧道效应。

Electrical and Thermal Conductivity of Polymers Loaded with Conductive Filler

The electrical and thermal conductivity of composites consisting of high density polyethylene(HDPE) filled with carbon black(CB) and carbon fiber(CF) has been studied.The results reveal that the electrical conductivity increases with the filler volume fraction first slowly and then suddenly changes by several orders of magnitudes when filler volume fraction approaches a critical volume fraction(percolation threshold).There existed a conductive network formed by filler particles which passes through the polymer matrix at the percolation threshold.In contrast to the electrical conductivity, there existed no jump in the percolation threshold region for the concentration-dependent thermal conductivity.Thermal conductivity could be well fit using the thermal model in which particles with high thermal conductivity dispersed in low thermal conductive matrix.The electrical conduction mechanism is considered to be touching conductivity and also tunneling conductivity.