The Effect of Electrical Stressing History on the Slow Polarization of Nano-SiOx and Low-density Polyethylene Composite

The composite of nano-SiOx and low-density polyethylene is prepared with the double-solution method. Charging currents of the composite at same dc stress, as well as discharging currents, are recorded with Keithley 6517A. It is found that the curves of charging and discharging currents decrease with charging times. Transferring those charging and discharging currents from time domain into frequency domain with Fourier Transform method, it is found that the shapes of the dielectric loss spectrum vary with charging times and the loss peaks appears shifting to the low frequency area for the nanocomposite. At the same time, electrical stressing has different effect on dielectric loss in the nancomposite or pure LDPE, which have close relation with traps of the interfaces between nano-SiOx and polyethylene, as well as carriers´ trapping and de-trapping in those interfaces