Sustainable Kerala rice husk ash for formulation of basic tyre tread: Taking first step

Abstract

From a ‘Waste to Wealth’ standpoint, sustainable conversion of agricultural waste materials into value-added products is of crucial importance. The study compares the BET surface area of 5 different rice husk ash varieties: Jyothi (RHA), Jaya (RHA-1), Kanchana (RHA-2), Uma (RHA-3), and Valichoori (RHA-4). The different rice husk ashes were prepared through the calcination of dried rice husk at 700 °C for 2 h. The resulting rice husk ashes and commercial silica (CS) were characterized using FT-IR, XRD, SEM, TEM, DLS, XRF and BET surface area. For the first time, we report on the potential of Kerala rice husk nanoash (Jyothi variety-RHA) with a high surface area (79.33 m2/g) in the development of a basic tyre tread. Natural rubber (NR) composites were prepared by replacing 5phr of carbon black (CB) with 5phr RHA, and 5phr commercial silica (CS). The different composites prepared were designated as NRCB50 (with 50phr CB), NRCB45RHA5 (with 45phr CB and 5phr RHA), and NRCB45CS5 (with 45phr CB and 5phr CS). A comparative study with NR-NEAT (with no filler) was also conducted. The cure rate index was higher for RHA-filled vulcanizates compared to RHA-free composites. Except for abrasion resistance, mechanical properties of NRCB50 and NRCB45RHA5 composites were comparable. The thermo-gravimetric analysis revealed onset degradation temperature ranking as NRCB45RHA5˃NRCB50˃NRCB45CS5. Moreover, dynamic mechanical analysis (DMA) showed no obvious loss in glass transition temperature (Tg). The loss tangent (tan δ) values at 60 °C and 0 °C suggested that the rolling resistance can be significantly reduced by replacing 5phr CB with 5phr RHA without affecting the ice traction.