Effect of type and thickness of core on mechanical properties and thermal conductivity transfer of SIP made of poplar OSB

One of the most important issues in a building is energy saving with adequate resistance throughout the structure. In this regard, structural insulation panels (SIPs) have always been considered as viable options because of their advantages such as providing robust structures, insulation, economical construction and energy conservation. The purpose of this study was to investigate the mechanical properties and thermal conductivity of building SIP made with poplar OSB as skin layers and two types of core layers (expanded polystyrene and air) in two thicknesses of 2 and 4 cm. OSB was made by hand-justified poplar strands in three layers perpendicular to each other using phenol-formaldehyde glue. Then the SIPs were made and the solid wood was used as a frame for core layer of panels. Then, SIPs and test samples were prepared in standard dimensions followed by experimental testing of bending, compression parallel to fibers, withdrawal strength of adhesive line, and heat transfer. Statistical analysis and the results showed that by changing the core type from air to polystyrene all mechanical strengths of the building insulation panels increased. Increasing the thickness of the core layer also had a positive effect on the mechanical properties of the building insulation panels. Moreover, the type of core layer of air and polystyrene had no significant effect in the thermal conductivity, however, increasing the thickness of core layer had a positive effect on increasing the thermal resistance in both types of panels.