MODELLING THE INFLUENCE OF RICE HUSK-SAWDUST BLEND AND NATURAL BINDER TYPE ON AGRO-WASTE PARTICLEBOARD PROPERTIES

Abstract

The valorisation of agricultural and wood-processing wastes into particleboard presents a sustainable alternative to conventional wood-based panels. This study investigates the main effects and interaction on the base material composition (rice husk, sawdust, and their hybrid blend) and natural binder type (para rubber sap and starch) on the physical properties of particleboard using a 3×2 factorial design (n = 18). Analysis of Variance (ANOVA) revealed that both the base material and binder type had significant effects on particleboard density and mass (p < 0.01). The two-way ANOVA showed that both base material (F = 192.47, p < 0.001) and binder type (F = 86.34, p < 0.001) significantly influenced particleboard density. A significant interaction effect between base material and binder type was also observed (F = 8.92, p = 0.002). Among the base materials, rice husk boards exhibited the highest mean density (25.0 ± 4.5 kg/m³), followed by hybrid boards (22.8 ± 4.2 kg/m³), while sawdust boards had the lowest mean density (13.1 ± 1.6 kg/m³). Starch binder increased density by approximately 6.42 kg/m³ compared to para rubber sap. Hybrid boards exhibited optimal dimensional stability (-33.07% to -40.94% thickness change). Multiple regression models demonstrated strong predictive capability for density (R² = 0.93) and mass (R² = 0.90). The regression equation _density = 11.24 + 0.153X₁ + 4.86X₂ + 0.021X₁X₂ confirmed rice husk proportion as the dominant densification contributor, with starch contributing an additional 4.86 kg/m³. This interaction is attributed to enhanced capillary penetration of starch into porous rice husk surfaces. These findings provide a validated quantitative framework for predictive design of sustainable particleboards from locally available agro-waste, addressing deforestation and waste disposal challenges while supporting circular economy objectives.