Reprocessable and robust crosslinked elastomers via interfacial C N transalkylation of pyridinium

Abstract Covalently cross-linked elastomers with high elasticity are widely found in daily life and high-tech areas. However, the irreversibility of the crosslinked networks hinders the rubber products from reprocessing or recycling, causing a major environmental problem. Recently developed vitrimer chemistry provides fantastic avenues for cross-linked elastomers to achieve full reprocessability and recyclability. Herein, we disclose a novel C N transalkylation of pyridinium by model studies and implant this chemistry into the interfaces of an elastomeric composite. As a proof of concept, (3-bromopropyl)trimethoxysilane modified silica was used to crosslink butadiene-styrene-vinylpyridine rubber, forming pyridiniums in the interfaces. The composites were prepared by straightforward mechanical compounding and subsequent hot-pressing. Because of the covalent interfacial bridges and excellent dispersion of silica, the composites possess robust mechanical properties. Furthermore, the C N transalkylation reactions of pyridiniums at elevated temperature endows the composites with vitrimer properties, such as malleability and reprocessability. As the pyridine moieties can be easily introduced into a great variety of commercial polymers, we envision this newly demonstrated C N transalkylation of pyridinium possesses significant potential in broadening the gallery of vitrimer materials.