Hybrid Graphene Oxide/Carbon Black Reinforcement in Natural Rubber: A Sustainable Approach for Multifunctional Tire Tread Compounds

Abstract

Carbon black (CB) is the primary reinforcing filler in tire tread elastomers; however, high filler loadings increase hysteresis and accelerate aging. In this context, hybrid reinforcement strategies incorporating graphene oxide (GO) have attracted considerable attention due to the unique mechanical and thermal properties of this nanomaterial. This study evaluates a laboratory-scale, industrially compatible approach for GO incorporation through conventional two-roll-mill mixing, using processing oil as the dispersion medium. Elastomeric formulations with GO loadings of 0.5–1.25 parts per hundred rubber (phr) were prepared and evaluated for rheological, mechanical, dynamic mechanical, morphological, and thermal conductivity properties. Overall, GO incorporation did not significantly alter the cure characteristics or conventional mechanical properties of the compounds. Nevertheless, NR/CB/GO_0.75 showed the highest retention of tensile strength after thermo-oxidative aging and a 10.6% increase in thermal conductivity, whereas NR/CB/GO_1.25 exhibited a favorable tan δ profile. The latter formulation showed higher tan δ at low temperature and lower values at elevated temperatures, suggesting potential improvements in wet-grip-related response and reduced hysteretic losses, respectively. Although the oil-assisted incorporation route did not produce substantial mechanical reinforcement under the investigated conditions, it showed potential for selectively modifying dynamic behavior, thermal transport, and the retention of mechanical properties after aging using conventional rubber-processing equipment. Further optimization of GO purity, dispersion stability, and filler-matrix compatibility is required before the practical and economic feasibility of this approach can be established.