DEVELOPING A RUBBER VULCANIZATE FOR THE TREAD LAYER OF SOLID TIRES USING RECOVERABLE CARBON BLACK AS FILLER

Abstract

The tire market is increasingly being challenged to replace traditional materials with sustainable ones without compromising on performance. There is one segment that has proved most promising, and that is the use of recoverable carbon black (RCB), obtained from waste tire pyrolysis, as a partial substitute for conventional carbon black (CCB) as an element of solid tire tread vulcanizates. This paper compares RCB and CCB physical and environmental properties, addresses modification techniques, and assesses hybrid formulation performance. RCB has equal tensile strength as CCB (19.5 MPa vs. 21.8 MPa), but issues such as ash content enhancement (15–21%), poor morphology, and lack of dispersion persist. Procedures after post-treatment like demineralization and steam activation considerably enhance the reinforcing effect of RCB. Notably, hybrid compounds of RCB have tensile strengths up to 27.2 MPa, a figure equivalent to high-end CCB grades. In addition to mechanical potential, RCB exhibits significant environmental and economic advantages of 40–50% cost saving in material and approximately 30% reduced CO₂ emissions. Regrettably, feedstock heterogeneity and non-standardized pyrolysis hinder reproducibility and standardization. In light of our findings, we recommend partial CCB substitution with RCB (30–50%) for non-critical tire use and urge standard pyrolysis protocols and scalable post-processing protocols. This work makes it possible to incorporate RCB into tire manufacturing as a viable step towards greener and more affordable production.