Space charge characteristics of epoxy-based nanocomposites filled with graphene oxide

Graphene oxide, a kind of nano-fillers with desirable thermal and electrical properties, could be added to epoxy resin and achieve satisfactory dispersion status due to its hydrophilicity, which lend great help to the preparation of samples. Graphene oxide could be mixed with water since its functional groups, O-H is in harmony with water's functional groups. Furthermore, epoxy resin, flexibilizer, catalyst and the solution of graphene oxide were blended together by ultrasonification and magnetic stirring. After the water was evaporated, the blend was put in vacuum oven for molding and curing. After the samples have been produced, the space charge behaviors were measured by pulsed electroacoustic (PEA) technique, with the temperature ranging from 40°C to 80°C. From the measurement results, how graphene oxide has changed the micro-structure of epoxy samples, and how the space charge behaviors have been altered could be understood, which could provide further guidance for future applications of this material.

I. Introduction

Epoxy resin has been used as the main insulation material in various equipment, for instance, electric motors, transformers, high voltage switches and insulators. The outstanding properties of epoxy resin, including advanced dielectric performances and high stability, have guaranteed the safety operation of equipment using it as insulation material [1]–[2]. However, the problems of electric field intensification are so serious that could bring potential harms and risks, which could further lead to discharges and electric breakdown.