A catalyst-free and recycle-reinforcing elastomer vitrimer with exchangeable links.

Vitrimers, as intriguing polymers, possess exchangeable links in the crosslinking networks, endowing them with the abilities of recycling and reprocessing. However, most of vitrimers are generally fabricated via complex synthesis and polymerization processes. Toxic and unstable exogenous catalysts are inevitably applied to activate the exchange reaction to rearrange the crosslinking networks. These drawbacks limit the widespread applications of vitrimers. Moreover, most reported vitrimers could only partially maintain or severely deteriorate their mechanical properties after recycling. Herein, to solve the above-mentioned problems, for the first time, a catalyst-free and recycle-reinforcing elastomer vitrimer is revealed. By the reactive blending of commercially available epoxidized natural rubber and carboxylated nitrile rubber, the elastomer vitrimer associated with exchangeable β-hydroxyl ester bonds was obtained. Strikingly, the vitrimer exhibits an exceptional recycle-reinforcing property. This work provides a feasible method to fabricate elastomer vitrimers, which promotes the recycling of crosslinking commercial available elastomers.