Polyurethane-based crosslinked polymer with tunable self-healable and mechanical properties

In practical applications, the scratch or damage of materials are inevitable. Self-healing materials are beneficial to the sustainable use of materials. Herein, the dual cross-linked self-healing polyurethane (PU-xUPy) were prepared by copolymerization of diisocyanate monomers, quadruple hydrogen bond chain extender based on 2‐ureido‐4[1H]‐pyrimidinone (UPy) and triol monomers. The PU-xUPy exhibit excellent mechanical properties owing to the covalent cross-linking via triol monomer and the noncovalent-linking via UPy. The tensile strength and elongation at break of PU-75UPy were 9.6 MPa and 420.1%, respectively. The self-healing efficiency of the tensile strength and elongation at break were achieved to 73% (the tensile strength is 7.0 MPa) and 72.7% (the elongation at break is 306.6%) after 24 h of healing at 40 ℃, respectively. Moreover, the cyclic fatigue tensile test provided the evidences of the breaking and recombination of hydrogen bonds. These promising outcomes are expected to promote the development of the sustainable application of polyurethane elastomers.