Effect of moderate high electrical field on dielectric and relaxation properties of pure polycarbonate

When an alternative or continuous electrical field is applied on polymers, its physical properties, such as dielectric relaxation from dipoles orientating in the electrical field direction, may be modified. In order to clarify the interaction between the applied field and dipole orientation, a pure model thermoplastic, poly-carbonate, has sustained dielectric spectroscopy measurements under different AC conditions between -100 and 200 °C. Dielectric spectroscopy allows following the molecular dynamics with temperature, by studying the variations of permittivity resulting from electric field application. The experiments were conducted with a variation of AC electrical field from 40 to 2000 V/mm. Only the conductivity and the β relaxation, associated with phenyl groups´ movements, were found to be affected. Both phenomenon intensities were observed to increase as the applied field increases.