Innovative Carbon Black Replacement in Rubber Compound: Impact of Pyrolytic Carbon Black and Energy-Gypsum By-Products on Vulcanization and Properties

This study focuses on the possibility of substituting the conventional carbon black filler N339 in a rubber compound, which also contains an energy-gypsum filler obtained as an industrial by-product, with an alternative carbon filler produced by pyrolysis of rubber waste. The proposed basic rubber compound recipe demonstrated excellent mechanical properties, which were also verified through industrial tests. Practical application in transport systems confirmed the reliability, durability, and robustness of the compound ensuring long-term functionality even in demanding operating conditions. From an ecological point of view, the substitution of conventional fillers with pyrolytic carbon materials is being pursued to reduce the environmental burden of the material. The rheological and vulcanization characteristics of the compounds were subject to minimal changes of up to 8%. The increase in the scorch time value of the compounds can be positively assessed given that the optimal vulcanization time has decreased, which leads to a faster course of the vulcanization process. The most significant effect was a 56% reduction in tensile strength without significant effect on elongation at break. These results document the potential for complete replacement of traditional fillers in rubber systems while maintaining several functional parameters.