Design and multi-response optimization of latex-stage mixed graphene–styrene butadiene rubber tire tread nanocomposites using Box–Behnken response surface methodology

This study reports the graphene-reinforced styrene–butadiene rubber (SBR) composites via the latex-stage mixing technique and the optimization of graphene loading in tire tread formulation using Box–Behnken design (BBD) and response surface methodology. The latex-stage mixing ensured uniform graphene dispersion, minimized agglomeration, and enhanced filler–polymer interactions. A three-factor BBD investigated the effects of graphene loading, partial replacement of carbon black, and treated distillate aromatic extract (TDAE) oil content on the processing, mechanical, and dynamic properties of the composites. Quadratic regression models accurately predicted the experimental responses. Graphene significantly reduced rolling resistance while improving processability. Carbon black remained as the primary reinforcing filler for tensile strength and abrasion resistance. Synergistic interactions between graphene and carbon black enhanced filler dispersion, reduced the Payne effect, and compensated for reduced carbon black loading. Multi-response optimization identified an optimum formulation comprising approximately 0.91 phr graphene (within the composite), replacing 8 phr carbon black, with 11.5 phr TDAE oil, yielding an overall desirability of 0.731. The optimized compound exhibited low tan δ (0.268), high tensile strength (∼21 MPa), satisfactory modulus, and controlled abrasion loss. Experimental validation closely matched model predictions, demonstrating that low graphene loading offers a scalable strategy for developing high-performance tire tread compounds with reduced dependence on conventional fillers.