Effect of Wood Extractives Clearing up on Adhesion Strength of Clear Coat in Wooden Furniture Surfaces

This study was aimed to investigate the effect of wood extractivesclearing up of Aspen (Populus spp) and Oak (Quercus spp) wood species on the adhesion strength of nitrocellulose (clear) and acid-catalyzed transparent finishes. In order towood extractives clearing up, industrial acetone and hot water (45°C) solvents were used. Specimens’ surfaces were sanded with 120 and 180 grate sizes sandpaper, respectively, and covered with the transparent finish in two separate processes with clear and acid-catalyzed coatings. The wettability of the specimens’ surfaces was evaluated by using the contact angle method. The adhesion strength of the transparent coating was determined according to Pull off method. The results showed that wood extractives clearing up had a significant effect on surface wettability and adhesion strength of coating so that these samples showed higher wettability and adhesion strength than that of control samples. The highest wettability and adhesion strength were found in the wood samples cleared up with industrial acetone solvent. In general, the highest adhesion (8.14 MPa) of coating observed in the oak specimens cleared up with industrial acetone solvent and covered with acid-catalyzed coating. The lowest adhesion (2.01 MPa) also was obtained in control specimens’ of Aspen coated with clear finish.