The Effect of Polyacrylate Emulsion Coating with Unmodified and Modified Nano-TiO 2 on Weathering Resistance of Untreated and Heat-Treated Wood.

In this research, the influence of titanium dioxide (TiO 2 ) nanoparticles and their modifications on the weathering resistance of untreated and heat-treated wood was studied. The wood samples were coated with polyacrylate waterborne emulsion coatings that contain nano-TiO 2 in the amount of 0.75 wt.%. Two types of modifiers were used to modify the nano-TiO 2 surface: 2,2'-azobis(2-methylpropionamide) dihydrochloride (AIBA) and 3-aminopropyltrimethoxy silane (AMPTS). Coated and uncoated wood samples were exposed to accelerated weathering by application of sunlight, water and moisture for 360 h. During the research, the dry film thickness, color, gloss and hardness of the surface of the samples were measured. The obtained results showed that the effect of the addition and surface modification of nano-TiO 2 on the color and gloss stability was different on untreated and heat-treated ash wood, and that accelerated weathering causes an increase in surface hardness and a decrease in thickness of the dry coating.