Electrical strength of a polymer for linearly increasing voltages

The breakdown strength E_b has been related to the rate of increase in the field strength for thin films of polyethylene terephthalate (3.0 m), polycarbonate (3.5 m), and phenylone (5.5 m). A voltage constant in sign and varying linearly in time was used with sphere — sphere electrodes in capacitor oil. The effects from partial discharges are slight under these conditions. E_b, increases linearly with In for all the polymers below room temperature. The measurements are compared with the calculated E_b() derived from Bailey's criterion and the assumption that the electrical ageing rate is related to the macromolecule breakage rate in the field. There is good agreement between theory and experiment. The parameters defining the failure kinetics have been determined.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 4, pp. 86–90, April, 1988.