Effects of Gamma Irradiation on the AC Electrical Properties of Cross-Linked Epoxy Resin/Bisphenol A-Based Polycarbonate Composites.

The effects of gamma radiation on the AC electrical properties of highly cross-linked epoxy resin/bisphenol A-based polycarbonate samples have been investigated as a function of concentrations of bisphenol A-based polycarbonate, frequency, and temperature. The composite samples contained different bisphenol A-based polycarbonate concentrations of 0, 4, 8, 10, and 15 by wt%. The gamma irradiation process was performed at different gamma doses of 0, 100, 300, and 500 Gy. The AC electrical properties of the tested samples were studied before and after gamma irradiation within a frequency range of 200 kHz to 1 MHz. The results show that after irradiation, a consistent decrease in complex impedance values ( Z ∗ ) was observed, indicating an increase in conductivity due to radiation-induced scission of the composite structure. Dielectric properties, including the dielectric constant ( ε r ) and dielectric loss ( ε i ), exhibited an increase with higher doses and higher polycarbonate concentrations, signifying the formation of defect sites and charge carrier trapping. AC electrical conductivity ( σ a c ) displayed a notable rise post irradiation, with temperatures ranging from 30 °C to 110 °C, and higher radiation doses and higher temperatures led to increased conductivity. The activation energy (   E a ) decreased as the radiation dose increased, reflecting structural modifications induced by radiation. [ABSTRACT FROM AUTHOR]