Fully Biobased and Mechanically Robust Elastomeric Vitrimer based on Epoxidized Natural Rubber and Dynamic Imine Bonds

Currently reported epoxidized natural rubber (ENR)-derived elastomeric vitrimers were usually limited by the poor mechanical properties and the utilization of nonrenewable chemicals to introduce dynamic cross-links. In this study, we report fully biobased and mechanically robust elastomeric vitrimers based on dynamic imine bonds prepared from ENR, vanillin, and 1,10-decanediamine. The fabrication procedures included two steps, i.e., preparation of a biobased dynamic cross-linker (DC) from vanillin and 1,10-decanediamine and subsequent cross-linking of ENR with the DC. The fully biobased elastomeric vitrimers (BEVs) with different DC/ENR ratios were prepared, and the effects of DC contents on the tensile properties, elasticity, stress relaxation, and reprocessability of the BEVs were investigated in detail. The BEV showed increased tensile strength and Young's modulus but reduced elongation at break with an increasing DC content. The robust BEV with a tensile strength of up to 19.44 ± 1.39 MPa and an elongation at break of higher than 880% was achieved by controlling the DC/ENR ratio. All the BEVs showed excellent elasticity with a strain recovery ratio of higher than 80% after stretching to 500%. The BEVs could relax stress rapidly at high temperatures, which endowed them with excellent reprocessability and thermal recyclability. With the combination of mechanical robustness, reprocessability, and recyclability, the fully biobased elastomeric vitrimers exhibit potential as fully sustainable substitutes to conventional ENR-derived permanently cross-linked rubbers.