Improved adhesive-bond performance in copper azole and disodium octaborate tetrahydrate-treated Eucalyptus grandis laminates

ABSTRACT The prospect of manufacturing durable structural laminated wood with copper and boron-based preservative-impregnated Eucalyptus grandis wood was previously investigated but revealed adhesive-bond performance below standard requirements. In this study, bonding process factors, viz. mechanical pretreatment (surface planing) and bonding pressure in conjunction with wood preservative and adhesive compatibility for improved bond performance in preservative-treated E. grandis laminates were investigated. The results obtained showed significant and satisfactory improvement in shear strength and delamination resistance of E. grandis laminates based on EN 14080:2013 [Timber structures — Glued laminated timber and glued solid timber — Requirements, BSI Stand. Publ. (2014) 1–110] requirements. The suitability of polyurethane, melamine-urea-formaldehyde, and phenol-resorcinol-formaldehyde adhesives for bonding copper azole (CA) and disodium octaborate tetrahydrate (DOT)-impregnated E. grandis wood was established. Satisfactory pathways, including greener process routes for manufacturing CA and DOT-impregnated E. grandis laminates for structural applications in tropical and subtropical climes were achieved. The established processes could be readily adopted industrially to enhance the global implementation of solid wood composites and promote hardwood bonding.