Critical Behavior of Electrical Conductivity for Reduced Graphene Oxide/Epoxy Resin Composites

Abstract

Abstract: In this paper, we analyze the dc and ac electrical conductivities, in the 240 to 400 K temperature range and 102 to 106 Hz frequency range, of a percolating system synthesized by mixing reduced graphene oxide (rGO) particles in insulating epoxy resin matrix, diglycidyl ether of bisphenol A (DGEBA). We found that the dc electrical conductivity of the samples is strongly related to the rGO content, indicating a percolating behavior with percolation threshold ≈ 4 %. The critical behavior of the dc electrical conductivity as a function of the temperature indicates a strong positive temperature coefficient and a negative temperature coefficient of resistivity below and above the transition temperature Tg, respectively. Moreover, the results showed that the dc conductivity obeys the Arrhenius law and the ac electrical conductivity is both frequency and temperature dependent and follows the Jonscher’s power law. Keywords: Composites, Dielectric properties, Fillers, Glass transition, Graphene.