Electrospinning nanofilms to improve sound absorption of flexible or rigid porous material

To further enhance the sound absorption capabilities of porous materials, we employed electrospinning technology to prepare electrospinning nanofilms using polyvinyl butyral solution. These nanofilms were then applied in varying thicknesses onto the surfaces of both flexible and rigid porous materials, specifically melamine foam and foam nickel. Utilizing an acoustic impedance tube testing system, we measured the sound absorption coefficient within the frequency range of 200∼6400 Hz. The results reveal that, within this testing frequency range, the electrospinning nanofilm modestly enhances the sound absorption performance of flexible porous materials. However, for rigid porous materials, the improvement in sound absorption performance exhibits more significant variations. As the thickness of the electrospinning nanofilm increases, its enhancement becomes notably pronounced in the mid-to-low frequency range, while slightly decreasing in the high-frequency range. In composite porous structures, which consist of a stack of flexible and rigid porous materials, the effectiveness of the electrospinning nanofilm in enhancing sound absorption performance varies depending on its application location. When applied onto the surface of rigid porous materials, the sound absorption coefficient is significantly improved at medium and low frequencies, albeit with a decrease at high frequencies. Conversely, when the nanofilm is inserted between rigid and flexible materials, it enhances the sound absorption coefficient across the entire frequency range. Electrospinning nanofilm offers valuable insights into enhancing sound absorption performance and sheds light on the development of novel lightweight sound absorption structures.