Sustainable Polyurethane Foam Composites Reinforced With Bio-Based Fillers From Industrial Waste for Electromagnetic Interference Shielding

The growing concern over polymer wastes and the increasing demand for recyclable and functional products has motivated researchers to develop new sustainable composite materials that can be recycled, reused or both. For this purpose, in this research study we developed eco-friendly electromagnetic interference (EMI) shielding composites. We used waste-derived polyurethane (PU) foam as our matrix material and carbon black (CB), bamboo charcoal (BC), and rice husk ash (RHA) as our filler materials. We included each of these different types of fillers at various proportions according to a central composite design (CCD) within response surface methodology (RSM). Following a dip-coating technique, which was followed by a drying procedure, we created samples from our composite material for use in an EMI shielding application in the frequency range of 8–12 GHz. Our optimized composite sample exhibited a shielding effectiveness of −34.64 dB. Our experimental results were very close to our predicted results of −35.54 dB, with a prediction error of 2.61%. Our structural and thermal studies were conducted via HR-SEM, TGA, and FTIR. This research demonstrates a potential method for converting industrial PU waste and agricultural waste into high-performance EMI shielding composites to support the principles of clean production and circular economy.