Effects of Electric Field and Temperature on Charge Transport in an LDPE/SiO Nanocomposite

The threshold electric field and temperature sensitivity associated with charge transport in an low-density polyethylene (LDPE)/SiO2 nanocomposite were investigated based on space charge and conductivity characteristics. The electric field ranged from 1 to 200 kV/mm, and the temperature was from 30 °C to 70 °C. A three-stage variation trend for space charge accumulation and conductance was observed with the rising of the electric field. Correspondingly, the threshold fields increased and decreased with the increase in filling concentration and temperature, respectively. The temperature self-sensitivity coefficient of space charge and conductance showed a single-peak trend, and the peak position was related to the maximum and minimum of the threshold electric field, respectively. The maximum temperature self-sensitivity coefficient of conductance and space charge increased after filling the nanoparticles, whereas the relative temperature sensitivity of conductance decreased considerably. The two threshold electric fields of space charge were lower than those of conductance, and the field difference between them increased with the increase in filling concentration and temperature. This phenomenon may be related to the modulation of various carrier transport processes by traps introduced by nanofilling.