Thermally stimulated depolarization current characteristic of EVA–conductive PPy composites

Abstract

Thermally stimulated depolarization current in pure poly(ethylene-co-vinyl acetate) and poly(ethylene-co-vinyl acetate) composites with different amounts of polypyrrole/carbon nanoparticles (of various weight ratios, 100:0, 95:5, 90:10, 85:15, 80:20, and 70:30) have been investigated at poling temperature 363 K using different polarizing voltage. Thermograms of pure and composite samples have two or three peaks over all temperature ranges depending on the polarizing voltage. The decrease in peak height with increased polarized voltage is observed in pure poly(ethylene-co-vinyl acetate) samples loaded with 5%, 10%, 15%, and 30% polypyrrole due to the detrapping of the large amounts of charge results in electrode blocking and decrease in thermally stimulated depolarization current in those samples. The molecular parameters, such as activation energy E, charge released Q, and relaxation times τ0 and τ m for thermally stimulated depolarization current peaks have been estimated.