The acoustic property study of polyurethane foam with addition of bamboo leaves particles

In this study, the acoustic properties of polyurethane (PU) foams produced with the biodegradable, easily disposable natural bamboo leaves particles (bamboo chips and bamboo stems) were investigated. Acoustical properties of PU foam composites as normal sound absorption coefficient and sound transmission loss were measured using a two-microphone impedance tube and a four-microphone impedance tube, respectively. The microstructures of PU foam composites were examined using scanning electron microscope (SEM) and air-flow resistivity was also measured. The results illustrate that suitable constituents of bamboo chips and stems have significantly enhanced the sound absorption and insulation properties of the PU foam composites over the entire frequency range, especially giving rise to a considerable improvement of low-frequency sound absorption and sound insulation characteristics. PU foam composites with 6% of bamboo stems obtain the highest NRC (noise reduction coefficient) value with 0.714 and the maximum value of the sound absorption coefficient is 0.971, achieved at 6,300 Hz. Besides, PU foam composites with 8% of 2-3 mm bamboo chips exhibit the best sound insulation with high transmission loss around 18.9 dB over the entire frequency range (100-6,300 Hz). POLYM. COMPOS., 39:1370-1381, 2018. (c) 2016 Society of Plastics Engineers