Effects of different additives in a waterborne olyacrylate coating on selected surface properties of heat-treated finished wood

Color changes of thermally modified timber due to different formulations of polyacrylate coating were studied before and after the application of the coatings. Olive leaf extract as a natural antioxidant-bearing additive was added to polyacrylate to examine any changes in color parameters in comparison with other additives. Water contact angle, surface roughness, and the color parameters in L*a*b* coordinates were measured, and any differences (E*, C*, H*, L*, a*, b*) were also calculated after applying the formulated coats on the thermally modified wood. The results indicated that lightness decreased after coating. The a* value was also increased after application of the olive leaf extract to the thermally treated wood. In general, total color change (E*) was increased after coating. Reduction of C* was found in the coating containing TiO2 with 10% antioxidant. Also, H* was increased by the use of the polyacrylate coating containing TiO2, compared with other coatings. Application of all of the formulated coatings on the wood surface led to improvement in the water contact angle over the evolution time. On the other hand, coating of the treated wood was responsible for the formation of a smooth surface in comparison with the uncoated thermally modified timber