Simultaneous aging of DGEBA/MeHHPA epoxy resin under thermal heating and gamma irradiation up to 1000 kGy

Stability Qualification of Resins/Metallic Oxide Composites for Surface Oxidative Protection

The accelerated degradation of alkyd resins via γ-irradiation is investigated using non-isothermal chemiluminescence. The stability qualification is possible through the comparison of emission intensities on a temperature range starting from 100 °C up to 250 °C under accelerated degradation caused by radiolysis scission. The measurements achieved in the samples of cured state resin modified by various inorganic oxides reveal the influence of metallic traces on the aging amplitude, when the thermal resistance increases as the irradiation dose is augmented. Even though the unirradiated samples present a prominent chemiluminescence intensity peak at 80 °C, the γ-processed specimens show less intense spectra under the pristine materials and the oxidation starts smoothly after 75 °C. The values of activation energies required for oxidative degradation of the sample subjected to 100 kGy are significantly higher in the composite states than in the neat resin. The degradation mechanism of polymerized resins is discussed taking into account the effects of fillers on the stability of studied epoxy resin at various temperatures when the degradation and crosslinking are in competition for the decay of free radical.