Insulator conductor transition in low-density polyethylene–graphite composites

The present paper reports the electrical conductivity of graphite filled low-density polyethylene composite in a broad range of composition. The observed non-percolation insulator conductor transition could well be explained in terms of the random resistor network of Miller and Abrahams model by considering the concentration of sites and size of the filler particle. The variation of the dielectric constant and dissipation factor has also been investigated. The dielectric constant and dissipation factor of low-density polyethylene–graphite composite increase with the increase in graphite volume fraction and significant changes were observed near the transition region. High values of dielectric constant and dissipation factor were observed in the low frequency region due to the Maxwell–Wagner interfacial polarization. A non-linear to linear variation of current density with electric field has been observed as the polymer composite transform to conducting region.