Effect of particle dimensions and pre-processing of nanoparticles in improving surface degradation characteristics of nanodielectrics

Abstract

Inclusion of nano-sized alumina and titania fillers in epoxy resin has been found to increase the resistance of the material to surface degradation, when exposed to surface discharges. In this paper, the work was extended to include Alumina platelets as opposed to spherical gamma-alumina nanoparticles. Nanoparticles with diameter of range 40-47 nm and platelets 200 nm in thickness and 5-10 mum in length were used as fillers to prepare polymer nanocomposites. After preparation, the polymer composites were investigated and characterized by Fourier Transform Infra-Red (FTIR) spectroscopy and Nuclear Magnetic Resonance (NMR) spectroscopy. The specimens were then subjected to degradation by continuous exposure to surface discharges under high electric stresses. The degraded surfaces were studied using a Scanning Electron Microscope (SEM). Surface roughness measurements were made using a Laser Surface Profilometer (LSP). Additionally, surfactants like Sodium Dodecyl Sulfate (SDS), functionalization of particles with 3-glycidoxypropyl-trimethoxysilane (GPS), and other particle processing techniques were utilized in preparation of nanocomposites being investigated. Nanocomposite specimens prepared with pre-processed nanoparticles were exposed to surface degradation tests in order to determine their effect on the bulk material properties. It was concluded that polymer composites with spherical nanoparticles as fillers have better resistance to surface degradation over unfilled epoxy, as well as polymer composites prepared with platelets. While use of surfactants like SDS in preparation of the nanocomposite failed to enhance its surface degradation properties as compared to unprocessed nanoparticles, pre-processing of the nanoparticles before use were seen to yield better results.