Mechanically robust and thermal stable polyurethane elastomers with self-healing and recycling ability

A series of supramolecular interaction-based polyurethane elastomers (SPUEs) were synthesized from the reactions of hexamethylene diisocyanate-functionalized 2-ureido-4[1H]-pyrimidinone (UPy) derivatives and polytetrahydrofuran (PTHF), followed by reactions with polyether amines. The tensile strength, elongation at break and toughness of the optimum SPUE system can reach 62 MPa, 693%, and 189 MJ·m −3 , respectively. All SPUEs have much higher tensile strength and toughness than the reference materials while maintaining large elongation at break owing to the increased hydrogen (H)-bonding sites and favorable crosslinked networks. SPUEs possess double glass transition temperatures and display good multi-shape memory behaviors resulting from different soft and hard domains. SPUEs have nanophase-separated structures, which endow them with excellent transparency within visible light wavelengths ranging from 500 to 800 nm. Owing to adequate H-bonds, SPUEs exhibit stress relaxation, shape-reconfigurability, and outstanding healing/recycling properties. The damaged SPUEs show high healing efficiency of 77–97% after heat treatment at 100°C for 12 h. The used SPUEs can be recycled multiple times by dissolving them in N, N-dimethylformamide (DMF) at ~110°C for 20–30 min, and the third recycled SPUEs can have high mechanical strength retention rate of up to 100%. Highlights Elastomer was constructed through H-bonds and favorable crosslinked networks. The elastomer has high comprehensive mechanical properties. The elastomer has extremely low and high glass transition temperatures. The elastomer has a high self-healing efficiency of ~97% after treatment at 100°C. The elastomer can be recycled multiple times.