Study of space charge characteristics in epoxy resin and its nanocomposites

In recent times, there has been increased awareness of the fact that space charge within an insulating material considerably governs its dielectric behaviour. In this work, we study the nature of space charge trapping and detrapping in epoxy specimens, with and without nano sized fillers. After application of a poling field for a specific period of time, depolarisation characteristics are obtained by removing the voltage and placing the specimen under short circuit conditions. The release of space charge from deep traps provides a current in the external circuit which is measured using an electrometer. Recombination and transit time is considered to be negligible. Trap depth is calculated on the basis of depolarisation characteristics. The trap depth distribution is studied with variation in specimen thickness, applied electric field and temperature. Further, the effect of ageing is studied. In order to estimate the effect of fillers, alumina and other nano fillers are incorporated into the bulk epoxy resin to investigate whether this affects the trapped charge distribution.