Nanoindentation and flammability characterisation of five rice husk biomasses for biocomposites applications

Abstract

Five different rice husks (RHs) having different geographical origins were characterised for their mechanical and fire reaction properties using nanoindentation and cone calorimetry, respectively. Analyses relating to ash and extractives contents, density and morphologies were also performed. The RHs had statistically similar extractives content, nanoindentation properties and peak heat release rates (PHRRs). The polypropylene-based composites made from these RHs also had insignificant differences in their tensile moduli, elongation and PHRR values. The RH inclusion conserved the tensile/flexural strengths while enhancing the moduli of the composites, as compared to the neat polypropylene. The material characteristics being ubiquitous amongst the different RH types enable the creation of biocomposites with foreseeable performance properties. Moreover, the individual nanoindentation and fire reaction properties of the RHs allowed the presaging of the bulk biocomposites’ properties using theoretical models. Good agreements between predicted and experimental moduli/PHRRs were achieved using rule of mixtures and Halpi-Pegano models.