Investigation of mechanical and thermal properties of polypropylene-based wood-plastic composites reinforced with silica nanoparticles

This study systematically investigates the synergistic effects of poplar wood flour and silica nanoparticles on the mechanical and thermal properties of polypropylene-(PP)-based wood-plastic composites (WPCs). While these materials are widely used in structural and semi-structural applications, maintaining a balance between mechanical stiffness, impact resistance, and thermal stability at high filler loadings often presents a practical challenge. To address this, the current work aims to optimize this dual-filler system to overcome such limitations. Composites were fabricated with wood flour contents of 30, 40, and 50 wt.% and nanosilica loadings of 0, 1, 3, and 5 wt.%, using 2 wt.% maleic anhydride-grafted polypropylene (MAPP) as a compatibilizer. Results showed that increasing wood flour content significantly enhanced tensile and flexural stiffness and strength but reduced impact resistance due to increased brittleness. The incorporation of nanosilica up to 3 wt.% further improved tensile and flexural properties; however, agglomeration at 5 wt.% diminished these gains. Finite element simulations conducted in Abaqus predicted the mechanical behavior and validated experimental trends, offering insights into stress distribution and failure mechanisms. The results demonstrate that tailoring the dual-filler composition enables the optimization of WPCs for targeted applications, balancing mechanical strength, impact resistance, and fire safety.