Recycling of waste tire by pyrolysis to recover carbon black: Alternative & environment-friendly reinforcing filler for natural rubber compounds

Abstract

The disposal of automotive waste tires is an increasing environmental problem worldwide. The recycling of waste tire is challenging because tires are produced by chemical cross-linking of polymer-filler materials. Among the diverse disposal methods available for waste tires disposal, pyrolysis is considered as a promising recycling approach. The pyrolysis method presents the possibility of transforming hundreds of tons waste tires into gaseous, liquid, and carbon-rich solid (RCB) fractions, mainly contains carbon fractions from conventional carbon black (CB) and inorganic ingredients used during tire building. Owing to numerous environmental concerns with the production and utilization of conventional CBs, a broad consensus among the industrialist is to replace CBs with equally effective material. RCB has the potential to replace the conventional CB in polymer matrix solving dual pollution problems. In this work, the RCB obtained from batch pyrolysis was investigated by Fourier transform infrared spectroscopy, scanning electron microscopy, and X-ray diffraction. The surface area of RCB estimated by the BET method, the DBP oil absorption test, was carried out to understand the structure of RCB. Although RCB exhibited low structure, the surface functional group found to contain acidic based complex material. Lastly, RCB was used in Natural rubber-based rubber compounds of general-purpose conveyor belts to investigate its practical feasibility as a substitute for commercial-grade N330 CB. Mechanical properties of the RCB reinforced composites found to be lower than the conventional CB loaded composites. However, limitations can be overcome by using a combination of RCB with conventional CB to obtain the optimal balance of reinforcement and targeted properties.