Compatibility of preservative with adhesive in Eucalyptus grandis laminates

ABSTRACT The fundamental factors responsible for the complexities in adhesive bonding of preservative-treated wood are predominantly wood species, preservative composition, and adhesive system. It is post-effect of these factors that process variables such as assembly times and bonding pressure exert secondary influences on adhesive-bond development in preservative-treated laminates. Hence, this study investigated the effect of copper azole (CA) and disodium octaborate tetrahydrate (DOT) impregnations on E. grandis heartwood (HW) and sapwood (SW) bonding with melamine–urea–formaldehyde and polyurethane adhesives. Based on the adhesives and bonding conditions investigated, the CA and DOT-treated E. grandis laminates do not satisfy at least one of the shear strength and delamination requirements according to EN 14080:2013. Contrary to delamination, shear strength was significantly affected by the HW–SW difference. This study established the basis for further considerations on adapting bonding conditions for improved adhesive-bond performance in CA and DOT-treated E. grandis laminates towards manufacturing durable hardwood composite for tropical and subtropical environments.