Thermal-based experimental method and kinetic model for predicting the composition of crumb rubber derived from end-of-life vehicle tyres

Abstract

End-of-life vehicle tyres are processed into granulised particles (crumb rubber) for reuse in various industries including building and construction. Crumb rubber compositions vary between batches due to the variability in the source of end-of-life tyres (EOLTs). Therefore, it is essential to develop cost-effective tools for rapid chemical (rubber) composition assessment of EOLT-derived crumb rubber to match engineering requirements. This study evaluated the effectiveness of a thermal-based (experimental and analytical) model in predicting the rubber chemical composition of EOLT-derived crumb exclusively sourced from passenger cars, light off-road vehicles and heavy trucks. A thermal degradation kinetic model based on thermogravimetric analysis (TGA) was used to predict the fractional weight of rubber components in EOLT-derived crumb rubber. Different rubber components present in the crumb rubber were confirmed via Fourier Transform Infrared (FTIR) spectroscopy. The thermal model predicted marginally higher natural rubber content (+5–6%) in heavy truck compared to passenger car tyre-derived crumb rubber. In contrast, the model predicted a slightly higher content (+5–6%) of styrene-butadiene in passenger car-derived crumb rubber. The thermal model successfully predicted the composition of EOLT-derived crumb rubber enabling rapid screening of such products to match engineering applications.