Effects of recycled carbon black generated from waste rubber on the curing process and properties of new natural rubber composites

This study assesses the potential use of recycled carbon black (rCB) generated from the waste rubber pyrolysis process as a substitute for conventional carbon black series N330 (CB) in new rubber products. The rCB and conventional CBs were characterized to find elemental constituents present. The experiments were performed by replacing CB with rCB to the natural rubber (NR) matrix at various loadings. Curing characteristics were determined by rheometer and differential scanning calorimeter (DSC). The kinetic parameters of the crosslinking reaction were obtained based on DSC data, using mathematical models that do not require a comprehensive understanding of the reaction model, such as Ozawa–Flynn–Wall, Kissinger–Akahira–Sunose, Starink, Friedman, and Vyazovkin isoconversional methods. The swelling degree, mechanical properties, thermal properties, and thermal stability of prepared vulcanized rubber composites were determined. The obtained results revealed that CB could not entirely be replaced by rCB, but it may be used by mixing with commercial CB (rCB content of less than 15 phr in the NR matrix), depending on the desired properties of the end products. Graphical abstract