Self‐healing polymers for aviation applications and their impact on circular economy

Abstract

Polymers have swiftly replaced conventional metallic materials in aviation due to their lightweight and easy processability. Usages of polymers are presently mostly limited to non‐critical components. Flight safety is paramount in aviation and overrides all other factors. The aviation industry is averse to the usage of polymeric materials in critical component applications owing to the nature of failure being catastrophic. The review has covered various polymeric component failures and their root cause reasons. To overcome the inherent weakness in polymers currently used, a strategy to mimic nature is being explored by researchers. Self‐healing polymers can overtake metals if coupled with safe fail technology. Such materials have additional advantages in terms of enhanced longevity and ultimate life cycle. This review critically analyzed various factors driving research and development of self‐healing material for aviation applications. Various extrinsic and intrinsic self‐healing materials have been reviewed in the present work. Composites with an extrinsic self‐healing mechanism possess good healability and strength and can potentially replace current materials. Further, candidate polymeric materials with intrinsic self‐healing capability for the aviation field are extensively reviewed. Various aviation‐grade polymers like epoxy, Poly(methyl methacrylate), polycarbonate, and elastomeric materials with possible chemistries of intrinsic healing like Diel‐Alder reaction, Shape memory assisted self‐healing and covalently adaptable networks have been critically examined. Authors believe that extrinsic self‐healing technology is mature enough for use in the secondary structure of aircraft. At the same time, present technologies of intrinsic materials are not mature enough for flight safety reasons in aircraft; however, they are candidate materials for UAVs. Fast‐growing aviation field, coupled with the entry of UAVs, calls for environmentally sustainable material support. Therefore, this review explores materials within the sphere of high mechanical properties coupled with a low environmental impact.