Polyimide-based materials with self-healing properties for lunar exploration mission

Currently, polymer-based materials with self-repair properties are emerging in the aerospace field. The integration of these materials into the design of spacecraft structures offers increased reliability and safety, enabling extended mission duration. Indeed, colonization and exploration missions imply the permanence of vehicles and space systems on our natural satellite over long periods and continuous exposure to micrometeoroids and lunar dust that can cause mechanical damage on the surface. Therefore, the choice of the optimal materials becomes crucial to the success of the mission. Among these, polyimides stand out due to their excellent properties. Polyimides possess high-temperature and chemical stability, outstanding mechanical properties, flame retardancy, and resistance to UV radiation, making them ideal candidates for the realization of structures in the lunar environment. The purpose of this work is to design, fabricate and characterize polyimide-based materials that are resistant to the hostile lunar environment, while having autonomous self-healing properties and shape memory functions. Poly(amic acids) (PAAs), precursors of polyimides, are synthesized from different combinations of aromatic diamines and dianhydrides in a non-toxic bio-based solvent. A selected additive, boric acid (BA) with strong hydrogen bonding capability, is embedded in the polymer material to endow it with intrinsic self-repair ability. Results are used to assess the potential use of PAA-based materials with self- healing properties for the protection against mechanical damage, for example caused by dust or micrometeoroid impact, in lunar environment.