Polyacrylonitrile/Polyurethane Nanofiber/Boron Nitride Nanosheet Sponges for Noise Reduction

The rapid development of modern society has brought serious noise pollution, affecting the quality of human life, thereby requiring high-efficiency sound absorption materials. However, most present noise-absorbing materials have difficulty achieving efficient absorption of both low-frequency and high-frequency noise. This study presents a facile strategy to directly synthesize rough nanofiber sponges with nanovibrating sheet structures (NSRSs) by humidity-induced direct electrospinning. The NSRS features a curled nanofiber network, which provides exceptional mechanical strength. It showed little damage after 500 stretching cycles and returned to its original state after compressive stress of 6000 times its weight. Moreover, the NSRS (11 mg·cm–3 volume density, 30 mm thickness) demonstrates remarkable acoustic attenuation (noise reduction coefficient (NRC) is 0.55), which originated from the synergistic effect of nanofibers’ viscous friction and nanosheets’ vibration to dissipate energy, achieving low-frequency absorption coefficients of 0.24 at 500 Hz and 0.93 at 1000 Hz while maintaining high-frequency absorption (coefficient of 0.98 at 2000 Hz). Particularly impressive was its practical noise attenuation effectiveness, achieving a 14.4 dB reduction for white noise and a 15.2 dB reduction for air compressor noise. These results indicate the rough nanofiber sponges with nanovibrating sheet structures provide a possible method to develop all-frequency porous acoustic materials.