Highly Conductive Polymer Composite Based on Graphite-Filled Immiscible Polyolefin/Epoxy Blends

Abstract

Conductive polymer composites (CPCs) based on polypropylene (PP)/epoxy (EP) and high-density polyethylene (HDPE)/EP blends filled with synthetic graphite (SG) were produced and characterized to explore their potential for high electrical conductivity applications. The polymer blends were chosen as matrices due to their immiscibility and potential to enable co-continuous morphology formation and preferential distribution of filler, which allows formation of maximized conducting networks. In-plane and through-plane resistivities of PP/EP/SG composites decreased from 0.083 Ω.cm to 0.015 Ω.cm and 10.16 Ω.cm to 0.31 Ω.cm, respectively, while for HDPE/EP/SG composites, in-plane and through-plane resistivities decreased from 0.086 Ω.cm to 0.014 Ω.cm and 5.02 Ω.cm to 0.24 Ω.cm, respectively, when SG content was increased from 30 to 80 wt%. The immiscible blend-based composites produced in this study have the potential to achieve significantly higher conductivity than filled single polymers due to concentration of filler in one of the polymer phases and the co-continuous structure of the blends. Also, resistivity anisotropy of the PP/EP/SG and HDPE/EP/SG composites generally decreased with increase in SG content, with HDPE/EP/SG composites showing lower resistivity anisotropy than PP/EP/SG composites at the same SG content.