Green Polyurethane Adhesive Bonding of Aluminum: Effect of Surface Treatments

Aluminum alloy 2024-T3 was treated by two different methods of surface treatments i.e. by alkaline etching and warm water treatment followed by silanization method in order to enhance the adhesive bonding. The effects of both the substrate surface condition and the adhesive properties on singlelap shear resistance were analysed. Three different formulation of polyurethane adhesive by varying the NCO:OH ratio which were prepared from polyol based on polycaprolactone (PCL)/palm kernel oil (PKO) with an aromatic and cycloaliphatic diisocyanate. Moreover, wettability tests were performed in order to evaluate the effect of all parameters mentioned above on the substrate/adhesive interaction. Surface treatment with warm water and ɣ-GPS gives better wettability and adhesive bonding compared to alkaline etching surface treatment.