Effect of Space Radiation on the Mechanical Properties of High-Strength Polyethylene Nanocomposite Films

This study experimentally investigates the effects of prolonged radiation exposure on mechanical properties of high-strength, highly crystalline polyethylene (PE)/thermally reduced graphene oxide (TrGO) nanocomposite films for space applications. Prior to irradiation, PE/TrGO films were found to have tensile strengths up to ~4 GPa, more than 40 times that of conventional space-deployed membrane films (e.g., those used in solar sails) and over 59× the specific tensile strength. The PE/TrGO films were subjected to three radiation conditions to simulate space environmental conditions: 90Sr beta radiation (0.2 to 2.5 MeV), 80 keV electron beam irradiation, and 4.9 eV ultraviolet (254 nm) exposure. Under exposure to similar total ionizing doses (TID ~2.5 kGy, corresponding to ~3% of the unshielded annual electron dose in GEO) in a vacuum environment, the tensile strength showed little change after high-energy Sr-90 beta irradiation, but decreased by up to ~34.8% following intermediate-energy electron irradiation. Mechanical and Raman spectroscopic analyses were conducted to elucidate the radiation-induced structural and chemical changes before and after exposure, as well as to assess the protective effects of incorporated antioxidants on the stability of the PE films.