Investigation on Low-Frequency Sound Absorption Properties of PVB Micro-/Nanofiber Membranes

In this study, polyvinyl butyral (PVB) was used as raw material, combined with electrospinning and microperforation process to prepare micro-/nanofiber membranes with excellent low-frequency sound absorption performance. To comprehensively explore the influence mechanisms of fiber diameter, multi-layer structure, and microperforated structure on the sound absorption performance, experiment and theoretical analysis were both conducted. Experimental results showed that appropriately reducing the fiber diameter, increasing the number of PVB membrane layers, and setting microperforated structure and cavity could improve the sound absorption performance in the low-frequency range. By adjusting the number of layers and the microperforation structure, the effective sound absorption band range of the fiber membrane can also be adjusted to better meet the sound absorption requirements. When the number of fiber layers was 20, the perforation rate was 1%, the perforation diameter was 0.6 mm, and the cavity depth was 40 mm, the PVB fiber membrane had peaks of 0.8483 and 0.9792 at 350 Hz and 480 Hz, respectively. Theoretical analysis showed that the acoustic electrical analogy model can well predict the resonance frequency and sound absorption peak of fiber membrane, and proved that microporous fiber membrane had both porous and resonant sound absorption mechanisms. These lightweight fiber membranes have great potential for application in sound absorption, such as in transportation, construction, and instrumentation.