Blends Comprised Waste Tires and Reinforcing Carbon Black: Effect of Mixing Sequence on Processing and Physical Properties

In this study, a simple recycling strategy for End-of-Life Tires (ELT) was described. The direct incorporation of a large-sized Ground Tire Rubber (GTR) as a major dispersed phase into the elastomer matrix was assisted by the promoter-induced mixing, which canceled the cost-consuming reclaiming step. A macro-dispersion of GTR in the mix was assessed via a surface roughness extent. This method allowed us to predict the behavior of the rubber compound. A nonuniform rough surface while the master step was converted to a smooth roll-processed web after re-milling. The processing steps were correlated with the fragmentation of GTR, partial interfacial adhesion, restoration of tack, and unsaturation. The sequential mixing generated a reasonable level of viscosity, building tack, and green strength. The structural integrity of the re-vulcanizates was provided with a higher curing temperature and was confirmed by the improved abrasion and tear resistance, retention of heat build-up, storage moduli values, and lower standard deviation compared to the unmodified GTR and neat NR/BR blends. The developed compounding and co-curing steps exhibit a practical way of GTR recycling using the standard mixer with lower operational and compound expenses, and the absence of toxic gas release.