Development, characterization and applications of a unique self-healable elastomer: Exploring a facile metal-ligand interaction

Self-healing polymers are one of the latest materials that can repair themselves when repaired by external action. We described a sacrificial network of carboxylated nitrile rubber crosslinked by metal-ligand coordination complexes that exhibit good tensile strength, excellent healing efficiency, recyclability, and potential for O-ring applications. At first, we have crosslinked the XNBR rubber by employing the metal salts with different counterions, namely, Zn(NO3)2 and ZnCl2, which build coordination complexes with the carboxylate ligand of XNBR rubber. The self-healing efficiency and mechanical properties of metal salts crosslinked compounds primarily depend on the nature of counterions and the ligand to metal ratio. The coordination crosslinked of XNBR rubber with 2 phr of zinc nitrate metal ion exhibits an excellent tensile strength of 4.2 MPa with excellent healing efficiency of 97.8% and 100% recycling efficiency at 40 °C temperature for 48 h.