Characterization of canola oil based polyurethane wood adhesives

A novel bio-based poly (ether ester) polyol containing both primary and secondary functional groups was synthesized from canola oil using a low cost and efficient procedure. In this work, use of the new canola oil derived polyol for the production of polyurethane (PU) adhesives was demonstrated. The canola oil based PU adhesives had similar or better adhesive properties in terms of lap shear strength than three commercial PU adhesives. The effect of NCO/OH ratio and temperature on adhesive characteristics on wood bonding was also evaluated by lap shear tests. It was found that the use of an elevated curing temperature (i.e. 100 °C), as well as optimized NCO/OH molar ratio (higher than 1.5/1.0), improved the wood adhesive properties. The overall chemical resistance of bio-based PU adhesives to cold water, acid and alkali was comparable to that of commercial PU adhesives whilst its resistance to hot water was superior.