Space charge characteristics of thermally aged epoxy based nanocomposite

Space charge accumulation has been identified as one of the principal aging factors in polymeric materials, typically through electric field distortion and energy dissipative processes. Thus characterization of space charge behavior in aging insulating materials is important. In this paper, we study the space charge characteristics of epoxy and an epoxy-based nanocomposite. Bisphenol-A type epoxy resin (LY 556) is used as polymer matrix. Aluminum oxide (size 40 to 47nm, density 3.97 g/cm³ at 25°C) is used as nano filler. Pulsed Electro-Acoustic (PEA) technique and Electroluminescence (EL) measurement using a Photo Multiplier Tube (PMT) operated in photon counting mode are used in order to estimate space charge accumulation. Further, we investigate the effect of thermal aging on space charge in epoxy and the nanocomposite. Aging is characterised by estimating material changes through X-Ray Diffraction (XRD) analysis and Fourier Transform Infra Red (FTIR) spectroscopy. The nanocomposite is found to exhibit lower space charge accumulation and a higher threshold field for aging.