Reversible Nonlinear Conduction in High-Density Polyethylene/Acetylene Carbon Black Composites at Various Ambient Temperatures

The reversible nonlinear conduction (RNC) in of high-density polyethylene/acetylene carbon black composites with different degrees of crosslinking was studied above room temperature and below the melting point of high-density polyethylene (HDPE). The experimental current density-electric field strength curves can be overlapped onto a master curve, suggesting that the microscopic mechanisms for the appearance of RNC exist regardless of the ambient temperature and the crosslinking degree of the HDPE matrix. The relationship between the crossover current density and the linear conductivity can be explained in the framework of the dynamic random-resistor-network model. According to these results, two electron-tunneling models are suggested to interpret the microscopic conduction behavior.