A KINETIC-MODEL OF TIME-DEPENDENT DIELECTRIC-BREAKDOWN FOR POLYMERS

A kinetic model of time-dependent dielectric breakdown for polymers is presented. The micromechanism of thermally activated bond-breakdown i s developed for polymers to account for the dynamical process of diele ctric breakdown. We first prove that the thermally activated polymer b ond-breakdown processes can explain not only the burst of a conducting pathway nucleated in any defect and the following successive propagat ion, but also the time-dependent dielectric breakdown strength of poly mers. The formulae for conducting microcrack growth rate and time to f ailure are derived and applied to the experimental data for polyethyle ne terephthalate films.