The Potential of Transparent Wood Biocomposites for Sustainable Acoustics Panel Membrane

Acoustic comfort is vital in indoor environments, and the demand for efficient sound-absorbing materials is increasing. While effective, traditional porous materials like rock wool and glass wool pose health risks due to the emission of fine fibers, leading to interest in safer alternatives, such as membrane-based panels. Transparent Wood (TW), a novel material created by removing lignin from wood, offers both sound-absorbing capabilities and environmental benefits. This study aims to evaluate the acoustic performance of TW-based membrane panels by investigating their sound absorption characteristics and the underlying mechanisms of absorption. Maple (Acer laurinum) and mahogany (Swietenia macrophylla) wood veneers were delignified with NaClO2 in an acetate buffer solution and H2O2, followed by polymer impregnation using epoxy resin. The sound absorption capabilities of TW were investigated through morphological analysis using Scanning Electron Microscopy (SEM) and acoustic performance testing via the impedance tube transfer function method. TW membrane panels have the potential to be sound-absorbing materials with absorption rates exceeding 20% at frequencies ranging from 400 to 3150 Hz. The highest absorption occurs at 630 Hz (α = 0.659 for maple wood and 0.603 for mahogany wood) and at 2500 Hz (α = 0.533 for maple wood and 0.548 for mahogany wood). The sound absorption mechanism of TW resembles that of a membrane absorber, in which the air cavity acts as an acoustic spring and the panel acts as the vibrating mass. By understanding the acoustic analysis in this study, it is hoped that TW-based membrane panels can be used as sustainable sound-absorbing materials.