Effect of High-Dose Gamma Irradiation on the Dielectric Properties of PVA Polymer Films

In this study, the effect of gamma irradiation on the dielectric properties of poly(vinyl alcohol) (PVA) polymer films were investigated.PVA films were prepared via the solution casting method and irradiated at doses of 250, 500, and 1500 kGy.Dielectric measurements were carried out in the temperature range of 293-373 K.The results revealed that the real part of dielectric permittivity (ε′) decreases with increasing frequency and increases with temperature for all samples.The influence of irradiation was found to be non-linear: ε′ decreased at 250 kGy due to dominant cross-linking, increased at 500 kGy owing to enhanced defect density and chain scission, and exhibited reduced temperature sensitivity at 1500 kGy because of structural stiffening.Electric modulus and AC conductivity analyses confirmed that the relaxation processes are thermally activated and strongly dependent on radiation dose.