The usage of carbon black (CB) obtained from agricultural wastes in the manufacture of bicycle tires and the examination of the physico-mechanical properties of the manufactured material

The rapid increase in the world population and corresponding rise in consumption rates have driven the tire industry to seek sustainable and environmentally friendly solutions. With growing awareness of the harm that waste products inflict on the environment, tire manufacturers and researchers have begun to investigate the use of natural waste materials in rubber compounds. The substitution of carbon black with alternative natural materials offers a promising solution for reducing carbon footprints by promoting the recycling of waste streams. In this context, recycling studies on biological wastes such as agricultural residues, food husks, and cellulose have grown substantially. Hazelnut shells, an agricultural waste product, are frequently preferred in recycling studies due to their low cost, high carbon content, and versatility in various industrial applications. In this study, the potential of using carbon obtained from hazelnut shells (HSC) as an additive in bicycle tire production was investigated. The usability of HSC in tire compounds was evaluated by comparing it with Carbon Black (CB), a commonly used filler in bicycle tire formulations. Bicycle tire formulations were prepared by maintaining a constant total carbon filler content of 28 parts per hundred rubber (phr). Initially, 28 phr of commercial carbon black and 0 phr of HSC were used. In subsequent formulations, the carbon black content was progressively reduced to 21, 14, 7, and finally 0 phr, while the HSC content was correspondingly increased to 7, 14, 21, and 28 phr to replace the reduced commercial carbon black. The five different formulations were characterized using various analytical techniques, including Mooney Viscosity (MV), Mooney Scorch (MS), rheological tests, physical-mechanical tests, Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM), Thermogravimetric Analysis (TGA), payne effect measurements, plunger tests, and rolling resistance tests. Tires have been successfully produced with all formulations. The formulation containing 7 phr HSC and 21 phr CB exhibited satisfactory results in both physical and dynamic properties. The results indicate that increasing the HSC content in bicycle tire compositions reduces mechanical performance, yet still meets the performance requirements for bicycle tire applications. The findings of this study demonstrate that HSC can serve as a sustainable alternative to CB.