Thermally stimulated relaxation and Electrical conduction phenomena in Polyacrylamide

Thermally stimulated relaxation (TSR), employingthermally stimulated luminescence (TSL) andthermally stimulated conductivity (TSC) asexperimental techniques, in Polyacrylamide (PAA)have been studied; in the temperature range 300 - 480K. Measurements of electrical conductivity ( ) atvarious temperatures, in the same temperature rangehave been made, in both as-grown and UV-irradiatedPAA films; to elucidate the mechanism of chargetransport in relation to the macromolecular relaxationsin PAA. Two TSL and TSC glow curves with maximaat 375 and 475 K have been observed. The log vs 1/Tplots showed two transition temperatures with changesin slopes; indicating the on-set of molecular motion inPAA. The TSL/TSC curves at 475 K are attributed tothe -relaxation near the glass transition temperatureof the polymer. The -relaxation is considered to beassociated with the glow curve at 375 K. Analysis ofTSL / TSC curves and electrical conductivity plotshave been made and the results are correlated. Thetwo endothermic peaks recorded by Differentialscanning calorimetry (DSC) are correlated with theTSL/TSC and - relaxations in Polyacrylamide.