Sound absorption properties of nanofiber membrane-based multi-layer composites

Aiming at the problem of poor low-frequency sound absorption performance of traditional fiber sound-absorbing materials, this work prepared nanofiber membrane-based multi-layer composites by lamination for sound absorption and noise reduction. By laminating polyvinyl butyral (PVB) nanofiber membrane with polyester (PET) fiber felt and polyurethane (TPU) film, bi-layer and three-layer composites structure sound-absorbing materials were manufactured, and the effect of lamination sequence and thickness of each layer on their sound absorption performance were investigated. The results testified that the composite structures have excellent sound absorption performance in low-frequency range while the nanofiber membrane was placed at the sound-facing surface. When the thickness of PVB was 2 mm, and the thickness of PET was 10 mm, the average sound absorption coefficient of PVB-PET structure composite reached 0.5646 in the low-frequency range. Notably, the frequency and peak of the first resonance sound absorption peak were 396 Hz and 0.8529, respectively, which can meet the needs of sound absorption and noise reduction. Another layer of TPU film was compounded on the backside of this structure, and the sound absorption peak was further transferred to the low-frequency range. The frequency and peak of the first resonance sound absorption peak of the three-layer composite structure material were 300 Hz and 0.7772, respectively. Compared to 10 mm thick PET fiber felts, the average sound absorption coefficients of both bi-layer and three-layer composite materials were improved by more than 200 % in the range of 100–1000 Hz. Additionally, the results of response surface optimization illuminated that the sound absorption of different frequency bands can be targeted through reasonable selection and optimization of structural parameters.