A kinetic model of time-dependent dielectric breakdown for polymers

Abstract

A kinetic model of time-dependent dielectric breakdown for polymers is presented. The micromechanism of thermally activated bond-breakdown is developed for polymers to account for the dynamical process of dielectric breakdown. We first prove that the thermally activated polymer bond-breakdown processes can explain not only the burst of a conducting pathway nucleated in any defect and the following successive propagation, but also the time-dependent dielectric breakdown strength of polymers. The formulae for conducting microcrack growth rate and time to failure are derived and applied to the experimental data for polyethylene terephthalate films.