Sustainable composites reinforced with glass fiber and bio-derived calcium carbonate in recycled polypropylene

This study investigates the development of recycled polypropylene (RPP) composites reinforced with glass fibers and snail shell particulates for sustainable applications. The primary objective is to enhance the mechanical, wear, thermal, and water absorption properties of RPP composites. Composites were fabricated with varying reinforcement contents (3–18 wt%) and evaluated for tensile, flexural, impact, hardness, wear, thermal conductivity, and water absorption properties. Notably, the 12 wt% reinforcement composite exhibited optimal performance, achieving the highest tensile strength (45.41 MPa), tensile modulus (270.09 MPa), energy at break (0.95 J), impact strength (16.44 J/m 2 ), and hardness (63 HS). Additionally, the wear index was minimized to 3.37 mg at this reinforcement level. These improvements are attributed to effective load transfer, strong interfacial adhesion, and uniform dispersion of the reinforcements within the polymer matrix. However, mechanical and wear properties declined at higher filler contents (15 wt% and 18 wt%), indicating that the system's optimal reinforcement threshold was surpassed. Thermal conductivity decreased with reinforcement addition, reaching the lowest value of 0.12 W/mK at 3 wt%, making the material suitable for insulation applications. These findings underscore the potential of hybrid synthetic/natural reinforcements to enhance the performance of recycled polymers, with the 12 wt% composite identified as ideal for automotive, building, and construction applications requiring lightweight, durable, and thermally insulating materials.