Plywood bonding with an adhesive based on tannins from Acacia mangium Wild. bark from trees grown in Northeastern Brazil

Abstract

This study evaluated the quality of plywood panels bonded with adhesives produced with tannins from the bark of Acacia mangium Wild. trees and compared their bonding performance with commercial adhesive formulations. Crude hot-water extract from the bark of A. mangium was employed to synthesize the adhesive formulation for plywood bonding. Twelve plywood panels with five layers were produced, four with each type of adhesive. Static bending strength, modulus of elasticity, modulus of rupture and Janka hardness were evaluated. Water absorption percentages were determined after immersion for 2 and 24 hours. Regarding mechanical properties, there was no statistical difference among the adhesive based on A. mangium and the commercial formulations. However, based on the water absorption results, plywood panels bonded with A. mangium tannins were found to be suitable only for indoor uses due to higher absorption compared to the other adhesives.