Thermally Stimulated Depolarization Currents and Thermal Sampling Technique of γ-Irradiated Gelatin and PVA Homopolymers and 50/50 (wt/wt %) Blend Sample

Abstract

Thermally stimulated depolarization current (TSDC) and thermal sampling (TS) method were used to systematically characterize the α-relaxation process in gelatin and PVA homopolymers and their blend sample of 50/50 (wt/wt %) composition. In addition, γ-irradiation effect on TSDC spectra of samples under investigation was studied. Measurements of TSDC at different polarizing field strengths, polarization temperatures and times made it possible to obtain a complete picture of kinetic transitions, local modes of motion and space charge polarization in one heating cycle. On γ-irradiation, the change in shape, position and area of the α-relaxation peak of the samples were attributed to the variation of distribution function of associated relaxation times. The thermal sampling procedure was applied to decompose the complex relaxations into their narrowly distributed components. The molecular parameters such as activation energy (Ea) and pre-exponential factor (τo) for TS processes have been estimated. A linear relationship between the activation energy and logarithm of pre-exponential factor confirms the existence of a compensation behavior. The compensation temperature Tc and compensation time τc for the present samples have been determined.