Developing structural sandwich panels for energy-efficient wall applications using laminated oil palm wood and rubberwood-based plywood/oriented strand board

In this work, a new type of structural sandwich panels made with laminated oil palm wood core and rubberwood-based oriented strand board (OSB)/plywood faces were introduced for energy-efficient wall applications in Thailand. Effect of the manufacturing process and material parameters including adhesive content (250 g/m 2 and 500 g/m 2 ), core configuration (cross or parallel laminated oil palm lumber) and density (low and medium) and face material type (rubberwood-based OSB/plywood) on panel’s properties were explored. The panels were produced using two-component polyurethane adhesive and a constant clamping pressure of 0.6 MPa. Adhesive content of 250 g/m 2 was found to be sufficient for gluing all layers, with wood failure percentage of more than 80% as required by the standard. In-plane dimensional stability of the panels was mainly affected by the core configuration; it was better for cross laminated oil palm wood core sandwich panel. Higher core density resulted in increased density, thermal conductivity and compressive strength in the major direction but lower thermal resistance of the panel. The plywood face sandwich panels provided slightly higher compressive strength than OSB face sandwich panel, and their failure mechanisms were also different. The heat loss of these panels was about one-third of concrete and brick walls, hence, they can provide better insulation for indoor space. Based on the measured thermal conductivity, it was expected that these panels would pass the energy criteria according to Building Energy Code of Thailand. Thus, from the energy saving and sustainability perspectives, these panels can potentially be used as energy efficient wall panels for buildings, not only for Thailand but also for other tropical countries, where the oil palm wood and rubberwood resource is available.