Effect of Electrical/Thermal Aging on Dielectric Properties of Polymer/SiO2 Nanocomposites

This paper deals with experimental results of the combined electrical and thermal aging of two epoxy resins with nanosilica subjected to AC voltages. Overall 20 samples were prepared. Ten samples contain laboratory epoxy resin DGEBA, hardener Laromin C260, and nanosilica. Other 10 samples contain industrially used epoxy resin Epoxylite also with nanosilica. These ensembles had been measured prior to ageing and then exposed for long-time. Samples were measured in the course of ageing in a time series after 100, 500 and 1000 hours. To determine the electrical insulating properties the following characteristics were measured: polarization index, volume resistivity, dissipation factor vs temperature, permittivity vs temperature and dielectric strength. The measurements and subsequent evaluation show that Epoxy resin ages slowlier than Epoxylite. Our benefit is two-factor and long-term aging of the nanocomposite and determining their dielectric properties.