Thermomechanical stability of graphene and multi-walled carbon nanotubes/epoxy nanocomposites under simulated lunar ultraviolet radiation

The renewed interest in lunar exploration requires advanced materials capable of withstanding extreme thermal cycles and unshielded solar ultraviolet-C radiation. Although lightweight epoxy resins are ideal for aerospace applications, they suffer from severe radiolytic degradation. This study evaluates the thermomechanical behavior and radiation resistance of epoxy-based nanocomposites reinforced with graphene nanoplatelets, multi-walled carbon nanotubes and their hybrid combination. The samples were subjected to accelerated environmental aging (a one-month equivalent lunar ultraviolet-C radiation dose) and analyzed via dynamic mechanical analysis in a temperature range from −150 °C to 130 °C and via scanning electron microscopy. The results demonstrate that the addition of carbon nanofillers significantly increases the storage modulus, with enhancements up to 30% for multi-walled carbon nanotubes. After irradiation, the nanocomposites effectively mitigate the loss of stiffness compared to the neat resin, protecting the polymer network from severe structural degradation. Furthermore, ultraviolet-C exposure induces a post-curing effect that shifts the glass transition temperature to higher values and suppresses secondary relaxations at cryogenic temperatures. In conclusion, these carbon-based nanocomposites exhibit excellent thermomechanical stability, proving to be promising and durable candidates for the design of future space infrastructures.