Comprehensive noise reduction performance of polyurethane/ferroferric oxide/activated carbon fiber felt coated flexible composites

Aiming at poor noise reduction performance of light and thin fiber aggregate materials, the polyurethane/ferroferric oxide/activated carbon fiber felt coated flexible composite materials were prepared by coating composite method. The effects of composite structure, ferroferric oxide particle content (10–25%), and coating thickness (0.25–1 mm) on the composites' sound absorption and sound insulation properties were systematically studied. The results show that with the increase of coating thickness and ferroferric oxide particle content, the sound absorption curve of the composite obviously moves to low frequency, and the resonance frequency decreases. When the particle content increased from 0% to 20%, the resonance frequency shifted 967 Hz. When the ferroferric oxide content is 25%, the maximum sound absorption coefficient and maximum transmission loss of the composite are 3.5 times and 25 times of that of the fiber felt, respectively. When the polyurethane/ferroferric oxide film thickness is only 0.1 mm, the maximum sound absorption coefficient and the average sound absorption coefficient of the composite are 3.5 times and 2.3 times of those of activated carbon fiber felt, respectively. Compared with single fiber felt, the composite material has better sound absorption, sound insulation, and mechanical properties while maintaining the thin and soft characteristics of the fiber felt.