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.

Adefisan, O. O. (2012). Production and testing of wood-plastic composites boards from mixed particles of Gmelina arborea and Khaya ivorensis. Journal of Tropical Forest Resources, 28: 1 – 6. Adhikary, K. B., Rizvi, G. M., Islam, M. R., and Park, C. B. (2010). Effects of Lubricant Content on Extrusion Processing and Mechanical Properties of Wood Flour-High-density Polyethylene Composites. Journal of Thermoplastic Composite Materials, 24(2), 155–171. https://doi.org/10.1177/0892705710388590 Amirta J. R., Suwinarti W., Kusuma I.W. and Wardhani I.Y. (2024), The physical properties of wood-plastic composite produced from red meranti (Shorea spp.) sawdust, polyethylene and polypropylene; JBES, V25, N3, September, P121-128 Ashori, A. (2008). Wood–plastic composites as promising green-composites for automotive industries! Bioresource Technology, 99(11), 4661-4667. Ayo A.W., Olukunle O. J., Oyerinde A.S. and Olutayo L. (2018). Physico-Mechanical Characterisation of Wood Plastic Composites Produced from Indigenous Trees in Nigeria. International Journal of Research -Granthaalayah, 6(2), 182–196. https://doi.org/10.29121/granthaalayah.v6.i2.2018.156 Bootkul, D., Butkul, T., and Intarasiri, S. (2017). Physical and Mechanical Properties of Wood Plastic Composites from Teak Wood Sawdust and High-Density Polyethylene (HDPE). Key Engineering Materials, 751, 277–282. Burgstaller, C., and Renner, K. (2023). Recycling of Wood–Plastic Composites—A Reprocessing Study. Macromol, 3(4), 754–765. https://doi.org/10.3390/macromol3040043Kajaks, J. Catto, A. L., Santana, R. M. C., Stefani, B. V., and Ribeiro, V. F. (2014). Influence of coupling agent in compatibility of post-consumer HDPE in thermoplastic composites reinforced with eucalyptus fiber. Materials Research, 17(Suppl 1), 203–209. https://doi.org/10.1590/s1516-14392014005000036. Chaharmahali, M., Tajvidi, M., Najafi, S. K., Mirbagheri, J., and Mirbagheri, Y. (2008). Mechanical and Physical Properties of Wood-Plastic Composite Panels. Journal of Reinforced Plastics and Composites, 29(2), 310–319. https://doi.org/10.1177/0731684408093877 Clemons, C. (2002). Wood-plastic composites in the United States: The interfacing of two industries. Forest Products Journal, 52(6), 10-18. Dvorak, W. S. (2004). The world view of Gmelina arborea: opportunities and challenges. New Forests, 28(2/3), 111–126. https://doi.org/10.1023/b:nefo.0000040940.32574.22 Ekhuemelo D. O. Onah A. A. and Tembe E.T. (2024). Physical and mechanical properties of wood plastic composite particle boards produced from the combination of Gmelina arborea and Khaya senegalensis sawdust and polyethylene terephthalate. Journal of Research in Forestry, Wildlife and Environment, 16(1): 49 – 61. Ekhuemelo, D. O., Tembe, E. T. and Aondoaver, M. T. (2021). Assessment of Physical and Mechanical Properties of three Hardwood Species from Timber Sheds in Makurdi, Benue State, Nigeria. Proceedings of the 7th Biennial Conference of Forests and Forest Products Society, Held at University of Uyo, Uyo, Nigeria. 26th - 30th April 2021 Guo, G., and Kethineni, C. (2019). Direct injection molding of hybrid polypropylene/wood-fiber composites reinforced with glass fiber and carbon fiber. The International Journal of Advanced Manufacturing Technology, 106(1–2), 201–209. https://doi.org/10.1007/s00170-019-04572-7 Guo, G., Finkenstadt, V. L., and Nimmagadda, Y. (2019). Mechanical properties and water absorption behavior of injection-molded wood fiber/carbon fiber high-density polyethylene hybrid composites. Advanced Composites and Hybrid Materials, 2(4), 690–700. https://doi.org/10.1007/s42114-019-00116-5 Hanana, F. E., Rodrigue, D., and Chimeni, D. Y. (2018). Morphology and Mechanical Properties of Maple Reinforced LLDPE Produced by Rotational Moulding: Effect of Fibre Content and Surface Treatment. Polymers and Polymer Composites, 26(4), 299–308. https://doi.org/10.1177/096739111802600404 Hejna, A., Przybysz-Romatowska, M., Kosmela, P., Zedler, Ł., Korol, J., and Formela, K. (2020). Recent advances in compatibilization strategies of wood-polymer composites by isocyanates. Wood Science and Technology, 54(5), 1091–1119. https://doi.org/10.1007/s00226-020-01203-3 https://doi.org/10.4028/www.scientific.net/kem.751.277 Ismail, R. I., Khor, C. Y., and Mohamed, A. R. (2023). Pelletization Temperature and Pressure Effects on the Mechanical Properties of Khaya senegalensis Biomass Energy Pellets. Sustainability, 15(9), 7501. https://doi.org/10.3390/su15097501 Kalnins, K., and Naburgs, R. (2017). Wood plastic composites (WPC) based on high-density polyethylene and birch wood plywood production residues. International Wood Products Journal, 9(1), 15–21. https://doi.org/10.1080/20426445.2017.1410997 Mothilal, T., Ragothaman, G., Manuel, D. J., Socrates, S., and Mathavan, S. (2020). Analysis on mechanical properties of plastic wood composite. AIP Conference Proceedings, 2283, 020037. https://doi.org/10.1063/5.0024893 Najafi, S. K., Hamidinia, E., and Tajvidi, M. (2006). Mechanical properties of composites from sawdust and recycled plastics. Journal of Applied Polymer Science, 100(5), 3641–3645. https://doi.org/10.1002/app.23159 Oladimeji, A. O., Agboola, F. Z., Oguntayo, D. O., and Aina, K. S. (2022). Dimensional stability and mechanical properties of extruded-compression biopolymer composites made from selected Nigerian grown wood species at varying proportions. Scientific reports, 12(1), 10545. https://doi.org/10.1038/s41598-022-14691-z Ramesh, M., Rajeshkumar, L., Sasikala, G., Balaji, D., Saravanakumar, A., Bhuvaneswari, V., and Bhoopathi, R. (2022). A Critical Review on Wood-Based Polymer Composites: Processing, Properties, and Prospects. Polymers, 14(3), 589. https://doi.org/10.3390/polym14030589 Ratanawilai, T., Taneerat, K., and Khamtree, S. (2023). Effects of polymeric matrix on properties of wood–plastic composites with rubberwood flour as filler. Iranian Polymer Journal, 33(2), 131–140. https://doi.org/10.1007/s13726-023-01242-0 Renner, J. S., Jiang, L., Mensah, R. A., Berto, F., Das, O., and Xu, Q. (2021). Fire Behavior of Wood-Based Composite Materials. Polymers, 13(24), 4352. https://doi.org/10.3390/polym13244352 Sahu, S. K., Liu, M., Wang, G., Chen, Y., Li, R., Fang, D., Sahu, D. N., Mu, W., Wei, J., Liu, J., Zhao, Y., Zhang, S., Lisby, M., Liu, X., Xu, X., Li, L., Wang, S., Liu, H., and He, C. (2023). Chromosome-scale genomes of commercially important mahoganies, Swietenia macrophylla and Khaya senegalensis. Scientific Data, 10(1). https://doi.org/10.1038/s41597-023-02707-w Sambe, L.N., Origbo, B. Gbande, S., and Ande P.U. (2021). Assessment of Wood Waste Generation and Utilization in Makurdi Metropolis: Implication for Sustainable Management of Forest Resources. Journal of Research in Forestry, Wildlife and Environment, 13(1): 188 – 196 . Samyn, P. (2024). Challenges for Wood–Plastic Composites: Increasing Wood Content and Internal Compatibility. Environmental and Earth Sciences Proceedings, 31(1), 1. Stark, N. M., and Rowlands, R. E. (2003). Effects of wood fiber characteristics on mechanical properties of wood/polypropylene composites. Wood and Fiber Science, 35(2),167-174. Thomason, J. L., and Rudeiros-Fernández, J. L. (2018). A review of the impact performance of natural Fiber Thermoplastic composites. Frontiers in Materials, 5. https://doi.org/10.3389/fmats.2018.00060 Varun K.S., Swamy S.R., and Darshan C. (2024). Comparative analysis of mechanical properties of Natural Fiber-Reinforced Polymer composites. International Journal for Research in Applied Science and Engineering Technology, 12(11), 735 - 745. https://doi.org/10.22214/ijraset.2024.65153