The effect of heat treatment on some electrical properties of polythene

The impulse electric strength of polythene film has been measured with and without a prestressing direct voltage of opposite polarity to that of the breakdown impulse after heating the polymer at several temperatures between 20 and 100 degrees C and quenching to room temperature. The steady-state electrical conduction through similar film specimens following identical heat treatment has also been measured. There was a correlation between breakdown strength with prestress, electrical conduction, and morphology as evinced by density changes.