Nylon/PVDF Spacer Fabric with Acoustic-Electric Conversion and Yarn Resonance Effect for Improved Low-Frequency Sound Absorption Property

The porous structure formed by the interweaving of yarns in textiles is favorable for sound absorption. However, the absorption of sound waves by porous materials conforms to the law of linear response, which leads to poor sound absorption of textiles in the low-frequency range. It is usually necessary to increase the thickness to improve the low-frequency acoustic absorption performance of textiles, which does not meet the performance requirements of lightness, thinness, width and strength. This work proposes a method to increase the acoustic absorption performance based on acoustic-electric conversion and yarn resonance effect. In the form of a woven spacer fabric structure, different parts of the structure were prepared using nylon and PVDF yarns with different triboelectric sequences to realize acoustic-electric conversion between dielectric materials. Control samples woven with the same material were also prepared. Further, the resonance frequency of the yarns was modulated by controlling their tension to change the resonant frequency corresponding to the maximum acoustic-electric conversion efficiency and sound absorption peak. It was found that fabrics composed of two different materials had better sound absorption than fabrics composed of only one material. This is because the larger triboelectric sequence difference between materials results in more charge transfer, which favors acoustic-electric conversion and acoustic energy consumption. A significant acoustic absorption peak at 390 Hz with a peak value of about 0.05 was observed for a fabric with a thickness of about 4 mm after tension adjustment. This study demonstrates that acoustic-electric conversion between dielectric yarns and proper tension control improves the acoustic absorption efficiency and provides a reference for the development of structures based on this novel acoustic absorption mechanism.