Acoustic absorption and thermal insulation of wood panels: Influence of porosity

The development of materials that offer environmental comfort inside buildings, through adequate thermal and acoustic behavior, has been as relevant as the search for raw materials of renewable origin. In this context, this study produced and characterized panels made with Pinus sp. waste materials, which were treated with a copper chrome boric oxide preservative and a castor-oil based polyurethane resin. The physical and mechanical properties of the panels were evaluated according to the ABNT NBR 14810 standard (2013). The panel porosity was investigated by scanning electron microscopy (SEM) and mercury intrusion porosimetry techniques. The sound absorption was analyzed by a reverberation chamber and thermal conductivity by the modified fractionated column method. Samples with a higher pressing pressure (4 MPa) during the manufacturing presented lower thickness swelling and higher mechanical properties in static bending. Panels made with a lower press pressure (2.5 MPa) resulted in a higher porosity volume (55.7%). The more highly porous panels were more acoustically efficient, with a sound absorption coefficient close to 0.8 at 3.2 kHz, and they had a better thermal conductivity performance.The potential of these panels for application where sound absorption and thermal insulation are prioritized is thus observed.