Influence of Applied Voltage and Temperature on the Current through the Alumina-filled poly(ethylene-co-butyl acrylate) Nanocomposites Under Constant Stress

Abstract

The current through the poly(ethylene-co-butyl acrylate) with 13 wt% of butyl acrylate (EBA) filled with 6 wt% of alumina nanoparticles with an approximate diameter of 45 nm was studied under constant stress application. The particles were either unmodified or surface-treated with aminopropyltriethoxy silane. The current was measured either until breakdown or for maximum stress duration of 10 minutes. Two voltage levels were chosen: 15 and 22.5 kV, which were low enough not to cause a breakdown during the ramping of the voltage at the rate of 490 V/s to the constant voltage level at room temperature. Several ramping rates {100, 260, 500, 1007} V/s were also tested for the reference unfilled material to evaluate its influence on the time to breakdown. Several temperature levels were tried: 20 (room temperature), 40 and 50 ºC.
As expected, higher applied voltage caused higher current through the materials, while higher temperature caused earlier breakdown as well as higher current. At the lower voltage level most of the materials survived the testing. At the higher voltage level most of the samples of the unfilled reference material failed at the temperatures above room temperature while most of the nanocomposite samples survived the testing even at higher temperatures.