Recovered Carbon Black ( RCB ): A Sustainable Alternative to Virgin Carbon Black for Tire Inner Liner Compound

ABSTRACT Waste tires pose a significant environmental threat to society. These tires are shredded into rubber powder or pyrolyzed to produce recovered carbonaceous black (RCB) and tire pyrolysis oil (TPO). However, to date, the application of this RCB is mainly limited to the non‐tire industry. This study comprises the utilization of RCB in tire inner liner compound with a specific dosage without compromising performance properties. RCB derived from waste tires was characterized by using various analytical tools. The surface area of the RCB is 75.5 m 2 /g comparable to that of virgin 3‐series black, whereas, the ash content is quite high compared to regular carbon black (CB). It contains high levels of zinc oxide (5.2%), silica (10.0%), and sulfur (3.5%), influencing the vulcanization kinetics and establishing a correlation between the amounts of RCB and various parameters. Mechanical properties of rubber compounds containing different doses of RCB, such as modulus, tensile strength, and elongation at break, show a clear relationship with the dosage of RCB. The dosage of RCB has an encouraging impact on air impermeability properties that are essential for tire inner liner compound. An optimum dosage (15 phr) of RCB is useful instead of virgin materials, considering the vulcanization thresholds, stress–strain properties, and gas permeability.