An exceptional strength, self-healing and recyclability polyurethane elastomers via multiple hydrogen bonds optimization strategy

Self-healing materials have the ability to recover mechanical performance, extend material lifespan, significantly cut costs, and bring solutions to present environmental challenges created by synthetic materials' slow decay or non-degradability. However, reconciling the contradiction between self-healing ability and mechanical strength remains a pressing challenge for self-healing materials. We have designed a polyurethane elastomer (SPU-AI), which exhibits high strength, toughness, self-healing properties, and recyclability. The polyurethane consists of an alicyclic hexatomic ring, urethane bonds, and flexible polyether short chains. Notably, thanks to the densely packed array of urethane bond hydrogen bonds, SPU-AI achieves a maximum tensile strength of 34.34 ± 2.36 MPa, fracture energy of up to 110.91 kJ m−2, and a fracture true stress of 410 MPa. Moreover, the energy dissipation of hydrogen bonds during the stretching process enables SPU-AI to achieve a maximum elongation of 1094 ± 95.2 % and a toughness of 152.48 ± 8.23 MJ m−3. On the other hand, due to the intermolecular hydrogen bond array and molecular chain migration, SPU-AI exhibits remarkable reparability, achieving a healing efficiency of 97 % in just 3 h at 80 °C. We have also proven its enormous potential uses in capacitive pressure sensors and 3D printing.