High Stretchability and Elastic Self-Healing Polyurethane Elastomer through Dual Cross-Linking with Metal–Ligand Coordination and Hydrogen Bonds

Herein, a high stretchability and elastic self-healing (SH) polyurethane elastomer is designed by introducing the ligand PDs with two hydrazides and one pyridine into the IPDI-type polyurethane elastomer backbone, which can guarantee the synergistic interplay of multiple dynamic bonds including abundant hydrogen bonds, strong cross-linking H-bonds (PDs–PDs), weak cross-linking H-bonds (urea and amine–ester bonds, etc.), and metal coordination bonds (PDs–Ce). The introduction of these dynamic bonds not only confers excellent SH properties but also enhances the mechanical characteristics of the material. The elastomer exhibits a remarkable tensile strength (11.3 MPa), exceptional stretchability (1336%), and high toughness (82.6 MJ m–3) as well as an impressive healing efficiency (ηH) reaching 91% after 24 h at ambient temperature. These characteristics are linked to the synergistic interplay of the weak H-bonds, dynamic strong bonds, and the metal–ligand bonds (PDs–Ce). Besides, the elastomer was applied in balloons, self-repairing tires, and membrane material, all of which show better performance, thus confirming the viability of the material as a high-performance SH elastomer material for various applications.