Sound Wave Absorption and Electromagnetic Wave Absorption Performance of Porous Composites With Waste Glass Fibers

This study realized high‐value recycling of waste glass fibers to relieve noise and electromagnetic pollution. Composites were fabricated via mechanical foaming, with waste glass fibers as reinforcement, polyvinyl alcohol (PVA) as matrix, and ferro ferric oxide (Fe 3 O 4 ) plus carbon black as functional fillers. Six parameters were optimized by single‐factor trials: 14% waste glass fiber, 8% PVA, 1.25% sodium dodecyl sulfate (SDS), 1300 rpm stirring speed, 4 min stirring time and 2 cm sample thickness. Under optimal conditions, the composite had an average sound absorption coefficient (SAC) of 0.48, noise reduction coefficient (NRC) of 0.50, along with a peak SAC of 0.86. Its minimum reflection loss (RL min ) reached −21.70 dB at 6.80 GHz. The composite displayed outstanding sound and electromagnetic wave absorption capacities. Stable porous structures prolonged wave transmission paths and strengthened multi‐reflection and scattering. Sound energy dissipated through viscous friction and heat exchange on pore and fiber surfaces. Fe 3 O 4 and carbon black attenuated electromagnetic waves via conductive, eddy current and interface polarization losses. The material achieved synergistic sound and electromagnetic wave absorption, offering practical technical support for waste fiber reuse and pollution control.