Sustainable polyurethane-based dielectric composites from industrial and E-waste for high-voltage insulation applications

The growing demand for sustainable materials in electrical and electronic applications has led to the reuse of industrial and electronic waste in high-performance polymer composites. In this study, rigid polyurethane foam waste (WRPU), recycled tire waste (RTW), and printed circuit board (PCB) scraps were incorporated as fillers into a polyurethane matrix using methylene diphenyl diisocyanate (MDI) as a binder. The composites were fabricated via mechanical stirring followed by hydraulic compression. Response Surface Methodology (RSM) using a Central Composite Design (CCD) was employed to optimize the filler composition for dielectric performance. The optimal formulation—15.94 wt% WRPU, 3.0 wt% RTW, and 10.0 wt% PCB—achieved a dielectric constant of 4.45. Confirmation experiments and simulations using COMSOL Multiphysics yielded values of 4.33 and 4.50, respectively, with minimal error margins. FTIR confirmed functional group integration, HR-SEM revealed uniform filler dispersion and strong interfacial bonding, and TGA indicated improved thermal stability. The results highlight the dielectric potential of recycled polymer composites as environmentally friendly dielectric materials, although further studies are needed on breakdown strength, dielectric loss and resistivity for assessing high-voltage insulation applications, such as battery cell separators and power systems.