Dynamic cross-links to facilitate recyclable polybutadiene elastomer with excellent toughness and stretchability

A facile cross-linking strategy of using small molecules as physcial crosslinkers to facilitate recyclable polybutadiene (PB) elastomer with excellent toughness and stretchability is demonstrated. Carboxylic acid groups were incorporated along the PB backbone via thiol-ene reaction, and then the polymer can be cross-linked by ionic hydrogen bonds between the carboxylic acid groups from PB and the amine groups of the cross-linkers. The ionic hydrogen bonds can dynamiclly break and reconstruct upon deformation, thus endowing the resultant polymer with not only high toughness and stretchability (∼1800%), but also good self-recovery and enhanced damping properties. Remarkably, the dynamically cross-linked PB elastomer can be thermally recycled owing to the thermal reversibility of the ionic hydrogen bonds and the mechanical properties can be largely recovered after reprocessing.