Improved breakdown strength at high temperatures through annealing of syndiotactic polystyrene

Abstract The improvement of the breakdown strength of polymer films is an essential scientific and applied research topic for high-voltage electrical power applications. Here, syndiotactic polystyrene (sPS) is annealed at different temperatures above the glass transition temperature so as to achieve dielectric improvement in both breakdown strength and dielectric loss. The breakdown strength of the annealed film can be increased by about 19.6% at 120°C compared with the original one. The dielectric loss is reduced by nearly 50% at high temperatures. It demonstrates a generalized phenomenon of annealing treatment of polymer films in facilitating further crystallization through chain packing or orientation, which limits the movement of charge carriers and polarization at high temperatures.