Mechanically robust, creep resistant and malleability retentive elastomer vitrimer enabled by integrating hydrogen bonds and boronic easters

Abstract

Vitrimer, featured with many fascinating properties, is a novel class of polymer, since their network topologies can be rearranged at elevated temperatures without the loss of crosslinking density. Although remarkable advances have been achieved in vitrimers, some of the published vitrimers are liable to creep and their mechanical strength are not always satisfied the specific applications. Herein, toward this issue, dual-crosslinked elastomer vitrimer was prepared by implanting supramolecular hydrogen bonds and exchangeable boronic esters into one single network. In detail, commercialized styrene butadiene rubber was firstly modified by N-Acetylglycine (NAg) to implant building blocks of hydrogen bonds, and subsequently crosslinked by dimercaptoborate (BDB) to introduce exchangeable boronic esters into vitrimer networks. The hydrogen bonds arisen between the grafted NAg moieties can function as physical crosslinks, thereby improve the overall mechanical properties remarkably by reversible breaking and reformation events. Besides, the hydrogen bonds crosslinks impose additional constraints on network strand diffusion, resulting in an improve the creep resistance. Moreover, the malleability and reprocessibility were not deteriorated by hydrogen bonds, as they can dissociate at high temperatures.