Electrical properties of graphene nanoplatelets/ultra-high molecular weight polyethylene composites

Abstract

Graphene nanoplatelets (GNPs)/ultra-high molecular weight polyethylene (UHMWPE) composites with a segregated structure had been fabricated using ethanol-assisted dispersion and hot compression at 180 °C. A percolation threshold of 3.5 wt% was achieved because of the formation conductive network. The positive temperature coefficient (PTC) and the negative temperature coefficient (NTC) effects of GNPs/UHMWPE composites had been investigated. The PTC behavior enhanced with increasing GNPs content but this was not always the case. The maximum PTC effect was observed in GNPs/UHMWPE composites (GNPs, 3.8 wt%) with the relatively low room temperature resistivity and the relatively high peak resistivity. The structure for GNPs/UHMWPE composites was examined by the SEM. The fact revealed that the slight interaction between GNPs and UHMWPE matrix may be changed by thermal cycles, and this can explain why thermal cycles could increase PTC and NTC intensity.