Synthesis of Diels–Alder bond and hydrogen bond synergistic shape memory self‐healing polyurethane elastomers

Abstract

Self‐healing materials exhibit the ability to repair damage and restore their function. Shape memory assisted self‐healing (SMASH) materials are smart materials that automatically close localized microscopic cracks and repair these cracks by bonding damaged surfaces. A novel temperature‐responsive SMASH polymer composite was established by introducing Diels–Alder bonds (D–A) in polyurethane. In this article, dynamic D–A produced by the polymerization of furfurylamine and 4,4’‐bismaleimidodiphenylmethane was introduced into the molecular chain to enable the polyurethane elastomers containing D–A bonds to acquire self‐repairing capability. The self‐healing properties of the synthesized material were examined using polarized light microscopy, which revealed excellent fracture healing. The mechanical properties before and after healing were tested, in which the initial maximum tensile strength of the material could reach 7.9 MPa, and the maximum tensile strength after self‐healing was 7.3 MPa, with a repair rate of 91.8%; the maximum elongation was 585.9%, and the maximum elongation after self‐healing was 469.5%, with a repair rate of 80.1%. In addition, this material has excellent repair performance for microcracks of different scales, and the micromolten part of the surface after heating can fill the micrometer cracks, play the role of antiaging, and extend the service life of the material.

A Highly Effective Self-Healing Waterborne Polyurethane Vitrimer Containing Conjugated Schiff Base Bonds Driven by Photothermal

“…After 25 min of exposure to visible light, the film successfully lifted a 7.0 kg bucket of water without breaking (Figure f). After comparing the healing efficiency, healing times, and mechanical strength of the 2-VPSB-WPU polymer with those of reported self-healing polymers (Figure g and Table S4), − it was evident that the mechanical strength of this material was higher in short healing times. Therefore, a balance of highly efficient healing properties and excellent mechanical strength was achieved by the VPSB-WPU vitrimer.…”