PHYSICO-MECHANICAL PROPERTIES OF HOT WATER MODIFIED MILKWEED WOOD (CALOTROPIS PROCERA) REINFORCED RECYCLED POLYPROPYLENE COMPOSITES

Abstract

This study reports the use of hot-water-treated Milkweed wood (Calotropis procera) particles as reinforcement in recycled polypropylene (rPP) to produce wood-plastic composites (WPCs). The incorporation of C. procera filler significantly improved the performance of the composites, particularly in samples containing treated wood particles. The highest tensile strength values were obtained at 20% filler loading for both untreated and treated composites of which their particulate sizes of 75, 150 and 300 µm gave the tensile strength values for the untreated to be 19.19, 18.8 and 17.41 MPa respectively and the treated values to be 26.62, 22.75 and 21.41 MPa respectively as well, an average increased value of 27% for each particle size. The flexural strength follows the same trend as tensile strength, with the optimum value occurring at 20% weight filler loading at 75 µm. The flexural strength obtained for 75, 150, and 300 µm for untreated composites was 20.15, 19.41, and 17.24 MPa, respectively, while the corresponding treated composites were 24.89, 21.85, and 20.15 MPa. Other mechanical properties increased with an increase in filler loading, while elongation at break decreased with increasing filler loading for both treated and untreated composites. Water absorption investigation revealed that treated wood/rPP composites were more resistant to water intake than the untreated milkweed wood/rPP composites. The water absorption (%) at 20% wt filler loading for each particulate size of 75, 150, 300 µm was: 8.31, 9.52, and 12.4% (untreated) respectively, and the corresponding treated wood/matrix were: 1.17, 1.45, 1.65% after 32 days immersion in water. The hot water treatment of milkweed wood enhanced the mechanical properties and water absorption resistance of milkwood/rPP composites. This study shows that hot water treatment is an eco-friendly, low-cost cost and sustainable pretreatment method that can significantly enhance the performance of wood-plastic composites, especially for outside door services without the extensive need for chemical modification