Microscopic investigation on the effects of wood surface modification with sol-gel method on the quality of polyurethane and alkyd coatings

In this research, the effects of poplar wood surface modification using sol-gel method on the quality of alkyd and polyurethane coatings for outdoor application were studied. For this purpose, the wood surface was modified with Tetraethoxysilane (T) sol-gel material. Then, solvent-borne alkyd (AS) and solvent-borne polyurethane (PS) coatings were applied. The quality of coatings was evaluated by microscopic observation using fluorescence, confocal laser scanning microscopy (CLSM) and EDX-SEM. The results of EDX showed a noticeable silicon peak in the sol-gel-treated specimens. The results of fluorescence microscopic studies showed that alkyd and polyurethane coatings only present in the cell lumens but the sol-gel penetrates into the cell walls. Laser microscope results showed that the modification of wood surface with sol-gel process reduces the roughness of alkyd and polyurethane coatings caused by weathering.