Lignocellulosic Fiber-Reinforced Sustainable Composite Plates: Structural, Thermal, and Radiation Shielding Properties of Waste-Based Materials

This work reports on the design, fabrication, and performance evaluation of sustainable composite plates produced from waste wood sawdust (WWS), industrial waste clay (WC), and zinc oxide (ZnO) via a simple hand-pressing technique. Structural analyses by X-ray diffraction (XRD) confirmed successful ZnO incorporation and a dose-dependent increase in composite crystallinity. Surface characterization through SEM revealed that ZnO addition modified surface roughness, with agglomeration becoming noticeable at higher loadings. Thermal stability assessed by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) demonstrated that composites containing 5, 12.5, and 25% ZnO exhibited, respectively, 12, 24, and 38 degrees C higher onset degradation temperatures compared to the WWS/WC base plate. Gamma-shielding capabilities were quantified using Am-241 (59.5 keV) and Cs-137 (662 keV) sources in a narrow-beam geometry: the WWS/WC/ZnO 25% sample achieved the highest linear attenuation coefficients (mu = 0.316 cm(-)1 for Am-241; mu = 0.104 cm(-)1 for Cs-137) and corresponding half-value layers (HVL = 2.19 and 6.66 cm). These results exceed those of ZnO-free composites by over 45%. Collectively, our findings demonstrate that ZnO-reinforced, waste-derived composites combine robust thermal performance with effective low- and medium-energy radiation shielding. This dual functionality underscores their potential as lightweight, eco-friendly shielding materials and highlights a viable route for valorizing industrial and biomass wastes into high-value protective products.