Field-induced thermally stimulated currents in poly (p-phenylene sulphide)

Thermally stimulated polarization currents (TSPC) have been investigated in poly p-phenylene sulphide (PPS) in temperature region 30-250 degreesC unde r various polarization fields. ranging from 3 to 18 kV/cm and with differen t heating rates. The effect of high temperature annealing on TSPC behaviour has also been investigated. The TSPC spectra show the presence of a single peak (P-1) around 110 degreesC. This peak has been attributed to a weak po lar nature of C-S linkage. A phenomenal rise of several order of magnitudes in the current dominated by conduction current is observed above 170 degre esC. During the successive cooling the current retains its positive polarit y and in the 2(nd) TSPC cycle the peak P-1 disappears due to temperature de pendence of saturation polarization confirming the polar nature of this pea k. The kinks observed in the TSPC spectra of annealed samples and with slow heating rates around 170 degreesC are due to the dipolar relaxation proces s associated with ether linkage, a cross-linked structure formed due to hig h temperature annealing. The thermal variation in dielectric constant. dedu ced from TSPC spectra is in good agreement at low temperature, with the res ult obtained by other method.