Green self -vulcanizable rubbers with recyclable, self-healable capabilities and excellent damping performance

Abstract

The vulcanization of rubbers is a prerequisite for their practicality. Currently adopted vulcanization methods for rubbers are suffering from some persistent problems, such as the utilization of harmful vulcanizing additives, the generating of volatile organic compounds, and the difficulties in the recycling of end-of-life rubbers. To meet the need of sustainable development, a facile and green self-vulcanization method is used to prepare self-healable and recyclable damping rubbers. Hydrogenated carboxylated nitrile rubber (HXNBR) and epoxidized nature rubber (ENR) can efficiently self-vulcanize by forming β-hydroxyl ester crosslinks without adding vulcanizing agent. Zinc oxide and epoxidized soybean oil are added as additives to adjust the self-vulcanization of HXNBR/ENR compound. Phenolic resin can make HXNBR/ENR composite to become a good damping material, and significantly improve the self-healing capacity of the composite. Additionally, the end-of-life self-vulcanized HXNBR/ENR composites can be recycled and reprocessed by selectively cleaving the ester bonds in the crosslinked structure, resulting in a very high recovery of mechanical performance of the recycled composites, which proves that this is a facile and efficient rubber recycling method.