Hysteresis effect in the electrical conductivity of graphene-enhanced polyethylene composites

Polyethylene nanocomposites based on commercial graphene nanoplatelets were prepared using either micro-extrusion or high-energy ball milling as compounding processes. Compression molded flat sheet specimens were made for electrical response measurements in the frequency domain using a two-electrode configuration. The electrical percolation threshold was found to be strongly depended on the fabrication process. Furthermore, when the applied AC electrical field was varied from 10 to 1000 V/mm, a strong non linearity in the conductivity as well as a hysteresis loop in the electrical properties was observed for samples in the vicinity of the percolation threshold.