Gamma-Irradiation of E-Glass/Epoxy Composite: A Study of its Mechanical and Thermal Sustainability

Abstract

Glass fibre reinforced epoxy (GRE) composites, used as mechanical support and thermal insulators for superconducting magnets of fusion reactors, have been exposed to gamma irradiations at both higher and lower order ranges of doses. Hand layed E-glass fibre/epoxy composite samples, exposed to gamma-irradiations of cumulative doses of both low strength (10, 20, 30, 40, 50 and 60 kGy) and high strength (0.5, 2.5, 6.5, 8.5 and 10.5 MGy) reveal a huge lowering of the ILSS (inter laminar shear strength) for its exposure to low strength dose irradiation. However, improved ILSS values are recorded for high dose exposures. At both high and low doses of exposure to irradiation the Tg (glass transition temperature) got improved initially with a decreasing trend towards the later stages of exposures. Thermo-gravimetric analysis (TGA) test reveals lowest initial decomposition temperature (IDT) for the composite sample irradiated to maximum dose (10.5 MGy). Activation energy () values of gamma-irradiated composite samples for thermal decomposition were found less compared to that for as-cured composite. FTIR spectra of irradiated samples reveal formation of oligomers confirming the trend of activation energy of irradiated composite. FESEM fractographs of the irradiated composite fracture samples reveal several modes of failure.