Development of sustainable polyurethane composites from e-waste and tire rubber for low-velocity impact applications in automotive structures

The growing demand for sustainable engineering materials has driven interest in utilizing industrial waste to create functional composites. In this study, a polyurethane matrix was reinforced with three recycled fillers—rigid polyurethane foam waste (WRPU), ground tire rubber (RTW), and waste printed circuit boards (WPCB)—using methylene diphenyl diisocyanate (MDI) as a binder. The composites were fabricated via mechanical mixing and casting, and their low-velocity impact resistance was evaluated experimentally. Various compositions were tested, and the optimal formulation (27.58 wt% WRPU, 15 wt% RTW, 2 wt% WPCB) exhibited the highest total energy absorption (2.699 J), closely matching ANSYS-based numerical predictions with minimal error. Microstructural analysis (HR-SEM) confirmed uniform filler dispersion and strong interfacial bonding, while thermogravimetric analysis (TGA) demonstrated improved thermal stability. The results support the feasibility of converting e-waste and rubber waste into impact-resistant composites for automotive applications.