Healable, recyclable and mechanically robust elastomers with multiple dynamic cross-linking bonds

The cross-linked network structure bestows rubber with excellent mechanical properties, but it greatly limits the self-healing and reprocessing ability of rubber. Herein, to address the above problem, we propose a simple cross-linking strategy with the cross-linker consisting of triple dynamic covalent bonds to vulcanize epoxidized natural rubber (ENR). A dynamic covalent network remarkably enhanced the mechanical properties of ENR through the combination of dynamic covalent bonds in the cross-linked network. At the same time, abundant dynamic covalent bonds rearranged the network topology through reversible exchange. As a result, a novel self-healing ENR with high tensile strength (2.06 ± 0.12 MPa) has been successfully developed. The ENR exhibits a high (97 ± 3%) self-healing efficiency (after 30 h at 70 °C) without applying any external force. Furthermore, it can be recycled more than three times. This work could enlighten researchers in academia and industry to develop self-healing elastomers with mechanical strength and reprocessing ability.