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 crosslinking 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 selfhealing elastomers with mechanical strength and reprocessing ability.