Changes in anatomical features, air permeability and sound absorption capability of wood induced by delignification treatment

To estimate the possibility of improving the sound absorption capability of wood by delignification treatment, the changes in anatomical features on the cross sectional surface, air permeability in the longitudinal direction and sound absorption capability of wood were evaluated. The intercellular substance gushed out and numerous small cracks were formed on the surface of the delignificated wood. Delignification treatment improved the air permeability of the wood in the longitudinal direction. The sound absorption coefficients of the delignificated wood were higher than those of normal wood over the entire frequency range studied and this trend increased with increasing frequency.