Degradation and Breakdown of Polymer/Graphene Composites under Strong Electric Field

In this work, we study the effect of strong electric fields on a polymer/graphene composite and resulting morphology upon its dielectric breakdown. Our model system was produced by compounding up to 0.25 wt % graphene nanoplatelets (GNP) into poly(ethylene-co-vinyl acetate) (EVA), which is soft polymer with low melt viscosity. A field 400 Vrms/mm applied EVA/GNP in melt. The sample’s resistance over application simultaneously measured. Despite GNP loading, below theoretical percolation threshold, conductivity during dramatically increased >10−6 S/cm 5 min before reaching current limit experimental apparatus. Conductivity growth follows same scaling relationship that predicts rotation translation time GNPs as function strength. Since no significant alignment observed under transmission electron microscopy (TEM), hypothesized increase electrical due local treeing matrix, eventually leads breakdown composite. Electrical likely initiated agglomerates propagated through conductive channels formed progressive