Research on the Insulation Enhancement of Epoxy Based Nanocomposites with Plasma Treated Nano-alumina at High Temperature

To improve the thermal stability and insulation performance of epoxy resin (EP), the surface of alumina nanoparticles was treated by low-temperature plasma generated by a dielectric barrier discharge (DBD) device. The plasma-treated EP/alumina nanocomposites with a mass fraction of 1 wt% were fabricated. The space charge distributions of the specimens were measured at 90 °C. Moreover, the results were further analyzed in depth. The results showed that obvious negative charges were accumulated in the neat EP, which led to the electric field distortion inside the sample. The sample with nano-alumina could effectively inhibit the space charge in the sample, whereas enhanced the inner electric field. The nanocomposites prepared with plasma-treated nano-alumina has the best space charge distribution and the electric field distribution. It proved that the plasma treatment led to the improvement of the space charge of the nanocomposites. The plasma-treated nano-alumina significantly increased the charge injection threshold, suppressed the internal electric field distortion, and suppressed the space charge accumulation and dissipation of the EP. It was elucidated that plasma-treated nano-alumina particles can effectively reduce deep trap density, trapped charges, charge injection and transportation and improve composites' insulation performance at high temperatures.