High field dielectric dissipation factor of polyethylene

The dielectric dissipation factor of polyethylene films has been measured as functions of electric field, frequency and temperature. The dissipation factor increases with electric field gradually, which may be attributed to the carrier transport process. The curve of dissipation factor vs. temperature at 100Hz has two absorption peaks for low density polyethylene films. The peak in the low temperature side may be due to the dielectric relaxation of carbonyl groups in side chains and the high temperature peak to the interfacial polarization. The dissipation factor enhanced by electric field decreases with time of the electric field application which may be caused by both the morpholgical structure and electrical conductivity changes of the sample.