Effects of γ-Irradiation and Sample Aging on the AC-Electrical Properties of Epoxy/ZnO/CB Hybrid Nanocomposites

Abstract

The goal of this paper is to study the effects of gamma irradiation and samples’ aging on the AC-electrical properties of hybrid epoxy resin as a function of frequency, temperature, and (zinc oxide) ZnO content (0, 0.049, 0.099, 0.149, and 0.199 wt) at 0.001 wt of conductive (carbon black) CB nanoparticles. The irradiation processes were administered at room temperature in a gamma chamber utilizing a Cobalt 60 source of average energy = 1.25 MeV with doses = 100, 750, and 1000 Gy. The AC-electrical properties, including the impedance, dielectric constant, dielectric loss, conductivity, and activation energy of the nanocomposites, were initially studied after years of sample preparations. The collected empirical data were later analyzed before and after the gamma irradiation. The results showed that exposing samples to different doses of gamma radiation affects these AC-electrical properties significantly. It was found that the energy gap decreased as the dosage of gamma radiation increased. This could be explained as the gamma-irradiation processes induce changes in the structure of the epoxy hybrid nanocomposites by reinforcing the metal–polymer bonding and hence, causing the release of more free electrons inside the hybrid nanocomposites. Moreover, the sample aging results showed that the AC-electrical conductivity decreased with time for all samples. Hence, this study demonstrated why the γ-irradiation technique can be considered a powerful way to treat, recover, and/or enhance the electrical features of the tested epoxy hybrid nanocomposites.