Dielectric behavior of aged polyethylene under UV radiation

The present paper reports the results of a study of dielectric aging of low-density polyethylene (LDPE) by UV radiation. The extruded polymer contained carbon black particles, approximately 3% in weight. The aging studies were made for polymer without and with carbon black. LDPE flat specimens were aged under UV radiation for up to 300 h, resorting to dielectric spectroscopy measurements in the frequency range from 10^-5 Hz to 10⁵ Hz. The dielectric susceptibility behaviors indicate the presence of relaxation peaks obeying the asymptotic forms of Dissado and Hill susceptibility functions. As the aging progresses, quasi-DC and flat loss processes may be observed in the low frequency range, for the LDPE specimens without and with carbon black, respectively. In addition, dielectric spectroscopy results have been compared with other results obtained with additional techniques such as Fourier transform infrared spectroscopy and scanning electron microscopy.