Healable and Recyclable Polyurea‐Urethane Elastomer with High Mechanical Robustness, Superhigh Elastic Restorability, and Exceptional Crack Tolerance

Abstract Developing the elastomer materials with high mechanical robustness through simple and environmentally friendly methods poses significant challenges. In this research, a simple solvent‐free polymerization method is reported to synthesize a transparent polyurea‐urethane elastomer using polycaprolactone (PCL) as soft segment and adjusting various hard segments. The target elastomer successfully combine acceptable mechanical performance and exceptional crack tolerance, whereby the notched samples can readily lift 25000 times (a rarely reported value) its weight. Moreover, the superhigh elastic restorability allow target elastomer recover to its original dimension from elongation over 5 times or to fracture. These results are attained due to the presence of densely and uniformly distributed hard microdomains within the elastomer, leading to effective energy dissipation. Furthermore, owing to the linear structure of the molecular chains and the reversible hydrogen‐bonding interactions between the chains, target elastomer can be conveniently healed and recycled under heating conditions. This research can provide a general and feasible strategy for the construction of elastomer materials with exceptional comprehensive properties, and the elastomers are expected to be applied in emerging fields such as protective elements and flexible electronics.