Sustainable recycling of polypropylene waste: Characterization and statistical analysis of wood husk-PP composite

The growing emphasis on sustainability and circular economy has driven extensive efforts in recycling and reusing polymer materials, widely used across various industries. While significant progress has been made in recycling polypropylene (PP), the development of polypropylene-ortho (PP-ortho) composite for prosthetics and orthotics remains underexplored. This study focuses on recycling PP-ortho waste by adding wood husk (WH) as a filler material for making PP-ortho composites for manufacturing assistive parts. Statistical analyses were performed considering PP, wood husk and particle size (PS) as input parameters to investigate the mechanical, thermal, and structural properties of the wood husk-PP composite. Differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) were conducted to investigate the thermal stability of the composite. The results showed that mechanical properties improved with reduced wood husk content and smaller particle sizes, with optimal conditions achieved at 90 wt% PP, 10 wt% wood husks, and a particle size of 125 μm. Thermal analysis indicated a slight reduction in thermal stability with increased wood husk content. The scanning electron microscopy (SEM) further confirmed that higher wood husk content and larger particle sizes led to weaker interfacial adhesion, fiber pullout, and reduced mechanical performance. This research advances sustainable recycling of polypropylene by developing composites for assistive parts in physical rehabilitation, bridging material science with impactful healthcare solutions.