Fecha de publicación: -- Fuente: Journal of applied polymer Lugar: RESEARCH ARTICLE A green technology to convert waste from polyurethane foam into an EMI barrier has been developed by coating it with Rice Husk Ash (RHA), Bamboo Charcoal (BC), and Carbon Black (CB). Optimization via Response Surface Methodology achieved an optimal SE of −34.64 dB over the 8–12 GHz frequency band; also, the results were validated via COMSOL simulation showing that the experimental values closely match the theoretical ones. Thus, this work demonstrates a new circular economy-based method for producing high-performance EM barriers.

ABSTRACT
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.