Quality of wood bonded joints of five species of eucalyptus with polyvinyl acetate and resorcinol-formaldehyde adhesives

Abstract

The objective of this work was to evaluate the potential of wood of Eucalyptus benthamii, Eucalyptus dunnii, Eucalyptus grandis, Eucalyptus saligna and Eucalyptus urophylla for the production of edge glued panels (EGP) and glued laminated timber (Glulam). Physical and chemical properties of the wood were determined based on the COPAN 461/459:1972 and TAPPI 204/252:2002 standards. Glued joints were manufactured in resin weights of 150 g m-2 and 200 g m-2 for polyvinyl acetate (PVA) and 200 g m-2 and 300 g m-2 for resorcinol-formaldehyde (RF). Bonding quality was evaluated by shear tests based on EN 13354-2008 standard document. All species presented medium to low basic density and medium to high contraction anisotropy. The total extractives content and pH are within the range referenced in the literature. The evaluation of the results based on the requirements of standard document EN 15353-2008 for the 5th lower percentile indicated that the E. benthamii, E. dunnii, E. grandis and E. saligna species showed high potential for the production of EGP with PVA adhesive, for indoor and outdoor use with coverage. For RF adhesive bonding, E. dunni showed better results, being indicative of its good potential for the production of glued laminated timber – GLULAM, for structural applications in the external environment. For both types of adhesives, the increase in weight did not affect the shear results of bonded joints.