Development and characterization of rice husk infused agro-composites for sole manufacturing

The widespread usage of petroleum-based sole materials in the footwear sector has significantly impacted the overall waste generation and carbon emissions. As a result, a major focus on waste valorization and sustainable product manufacturing techniques has subsequently evolved. This investigation aims to assess the feasibility of utilizing agricultural waste in manufacturing footwear sole materials. This approach will potentially minimize waste generation in the footwear sector during manufacturing, while contributing to the management of waste generated at the farming site. In this study, rice husk, an agricultural waste, has been used as a natural filler, with castor oil acting as a bio-plasticizer. The formulated Bio-TPR compound was injection-moulded to prepare footwear outsoles, and the material properties were evaluated in terms of structural, mechanical, and thermal parameters and compared with standard TPR soles. The Bio-TPR soles had shown better mechanical behaviour in terms of material hardness (shore A – 61.5), accelerated ageing (property change-null), tensile strength (3.85 MPa), and slip resistance (Coefficient of Friction in wet condition-0.4). Furthermore, analyses such as abrasion resistance, density, finite element analysis, and thermogravimetry had also shown comparable results with those of the control TPR, which cumulatively met the standard requirements for footwear outsoles. In essence, the developed Bio-TPR soles has proven to be a sustainable option for footwear, offering balanced physico-chemical properties as a way forward towards eco-friendly footwear solutions fostered through interdisciplinary circular economic practices.