Designing Self-Healing in Styrene–Butadiene Rubber via Polysulfide Crossover Reactions

The systematic and sustainable management of elastomeric waste remains a major enigma in the scientific community. The introduction of self-healing characteristics into elastomers via incorporating reversible cross-linking has several advantages like improvement in its lifetime, reprocessability, and recyclability which can reduce the elastomeric wastes. Here, we report a self-healable and recyclable elastomer based on styrene–butadiene rubber (SBR) using polysulfide metathesis reactions. The low molecular weight polysulfide rubber (PSR) was incorporated into the SBR matrix by blending it in an internal mixer to introduce polysulfide linkages. These polysulfide linkages undergo dynamic crossover reactions in the cross-linked networks of vulcanized rubber catalyzed by metal chloride catalysts. The SBR/PSR blend was compounded with different rubber compounding ingredients and was vulcanized. The PSR blended SBR demonstrated improved tensile strength with a high healing efficiency of up to 87%. However, the healing efficiency of SBR/PSR silica composites was less than the same without a silica filler due to the restriction of the segmental chain mobility. Thus, the SBR-PSR blend with polysulfide bridges may be a potential route to design self-healing and recyclable elastomers.