Sound absorption properties of natural Bari bamboo composite

This study investigates the sound absorption properties of Bari bamboo (Bambusa polymorpha) composites, using crumb rubber from waste tires and polyurethane binder (PU Binder). The objective is to evaluate the acoustic properties of panels made from different bamboo culm parts—internode and node fibers—and combinations with crumb rubber and air gaps. The samples’ sound absorption coefficient (SAC) was measured using the two-microphone impedance tube transfer function method. Results indicate that bamboo panels with node diaphragms achieve a SAC peak of over 0.9 at frequencies below 960 Hz. The incorporation of crumb rubber significantly improves sound absorption at lower frequencies, and air gaps shift the SAC peak to even lower frequencies. The study demonstrates that Bari bamboo composites, reinforced with crumb rubber, can be a sustainable and effective alternative to synthetic sound-absorbing materials. The highest SAC values were obtained from panels with node diaphragms and consolidated crumb rubber, which exhibited enhanced sound absorption performance. The introduction of an air gap further optimized the SAC at lower frequencies. This work highlights the potential of utilizing natural, biodegradable materials like Bari bamboo combined with waste-derived crumb rubber for sound absorption applications, offering an environmentally friendly solution for noise control.