Comparison of the bond strength of oak (Quercus L.) and beech (Fagus sylvatica L.) wood glued with different adhesives considering various hydrothermal exposures

Abstract

The investigation of the hydrothermal exposure effect on the glue-line strength is obvious when outdoor application of wood products is in option. In our research the bonding quality of oak (Quercus L.) and beech (Fagus sylvatica L.) wood was tested in different conditions according to EN 205. After each exposure the lap joint test specified the shear strength of wood bonded with PVAC and PU adhesive. In our research different behaviour concerning both types of adhesives and selected wood species was observed. The most significant decrease (-80%) of the shear strength was found when the PVAC was used to bond oak wood. Therefore the PVAC adhesive is most likely less suitable for the bonding of the block board in outdoor conditions. On the contrary, the best results in the same conditions were obtained by the oak when the polyurethane adhesive was used. It indicates that the PU adhesive is more suitable for the bonding of oak wood. Considering results of beech wood, there were not found this interaction.