Evaluating the physical, mechanical, and aesthetic properties of wood-plastic composites from Gmelina arborea, Khaya senegalensis, and high-density polyethylene blends

Abstract

Sawdust disposal and High-Density Polyethylene (HDPE) waste both cause significant environmental pollution through air, soil, and water contamination. Their improper management leads to harmful ecological impacts due to particulate emissions and plastic persistence.The objective of the studywas to assess how varying proportions of Gmelina arborea and Khaya senegalensis sawdust blended with HDPE affect the physical and mechanical properties of wood-plastic composites (WPCs).The composites were assessed for density, shatter resistance, modulus of elasticity (MOE), modulus of rupture (MOR), compressive strength, and surface characteristics.Results indicated that composites with higher K. senegalensis content exhibited superior performance across most parameters. The Highest Density (0.67 ± 0.48 g/cm³) was observed in the hybrid 60:40 K. senegalensis and G. arborea blend. Pure K. senegalensis composites demonstrated the lowest shatter index (5.78%) and highest shatter resistance (94.22%), surpassing pure HDPE composites. MOE and MOR values peaked at 10.43 ± 7.62 N/mm² and 478.88 ± 419.57 N/mm², respectively, in 100% K. senegalensis composites. The highest compressive strength (232.19 ± 89.75 N/mm²) was recorded in the 60:40 K. senegalensis and G. arborea blend. Surface analysis showed that increasing K. senegalensis content produced smoother textures and reddish-brown hues in the composites. This contrasted with the rough, black surfaces seen in pure HDPE composites. Adding K. senegalensis sawdust to HDPE improved both the structural and aesthetic qualities of the WPCs. The hybrid blend of K. senegalensis and G. arborea (60:40) achieved the highest density and compressive strength. These results indicate a synergistic effect between the two wood species, making the composites suitable for demanding applications.