UV‐Curable Polyurethane Elastomer with UV‐Irradiation/Thermo Dual‐Activated Self‐Healability

Abstract Self‐healable polyurethane elastomers have potential applications in many fields, however, their use is limited by single self‐healing mechanism, intricate preparation process, and long curing time. Herein, a UV‐irradiation/thermo dual‐induced self‐healing polyurethane elastomer is prepared by UV‐curing two kinds of acrylates, where one includes a quadruple hydrogen bond (PU‐UPy‐HEA) and the other contains a disulfide bond (SS‐MA). UV‐curing kinetics indicate that the conversion of acrylates is significantly improved by tuning the irradiation intensity, photoinitiator dosage, and SS‐MA content. A maximum conversion of 80% is achieved within 10 s under 200 mW cm −2 in the case of the 1.5 wt% photoinitiator. The tensile strength of UV‐cured polyurethane elastomer is notably improved by SS‐MA, whereas its elongation at break decreases. Tensile shear tests demonstrates that the bisected samples can be re‐bonded when they are repaired at 100 °C for 15 min, or under 200 mW cm −2 irradiation for 1 h. After that, ≈90% of shear strength is recovered and the strength is only slightly reduced after two healing cycles. Self‐healing mainly relies on thermally reversible hydrogen bonding interactions and UV‐induced disulfide metathesis. This UV‐cured self‐healable polyurethane elastomer can be used in smart coatings as well as in other fields.