Tough self-healing polyurethane elastomers based on interpenetrating networks containing multiple hydrogen bond networks, flexible blocks, metal coordination and covalent cross-linking

Currently, it is a challenge to prepare elastomers with high mechanical properties and high self-healing efficiency. In the present work, by mixing a polyurethane (PU) prepolymer with a PU elastomer containing 2-ureido-4[1H]-pyrimidinone (UPy) groups, we obtained a new PU elastomer based on interpenetrating networks. In this condition, four different structures coexist in the interpenetrating polymer networks: covalent cross-linking network, metal-ion coordination network, multiple hydrogen bond network and flexible blocks. The experimental results demonstrated that the presence of metal-ion coordination network, multiple hydrogen bond network and flexible blocks is beneficial for the improvement in healing efficiency, while the coexistence of covalent cross-linking network, metal-ion coordination network and multiple hydrogen bond network benefits to improve the mechanical properties.