Weathering performance of thermally modified wood coated with polyacrylate containing olive leaf extract as a bio-based additive

摘要

Heat-treated (HT) wood is now a popular building material, which has been welcome by consumers due to its dark brown color, dimensional stability and bioresistance. This wood has many advantages. However, its color is susceptible to changes due to weathering. Therefore, for any outdoor application, protection of the wood with proper coatings is obligatory. In the current research work, olive leaf extract has been added to polyacrylate coating to study any resistance against natural or accelerated weathering. The polyacrylate polymer blended with additives of nanoparticles of TiO2 or ZnO as well as 2-(2-hydroxyphenel)-benzotriazole (BTZ) type UV-absorber in combination with olive leaf extract or hindered amine light stabilizer (HALS) was investigated. For this purpose, HT wood samples were coated with a polyacrylate coating containing the mentioned additives. Afterwards, they were exposed to natural weathering for one year. The best samples, such as polyacrylate coated thermally treated wood with TiO2-olive leaf extract 20, BTZ-olive leaf extract 10 and 20 were selected after one year and exposed to accelerated weathering. The results showed olive leaf extract in combination with TiO2, BTZ had less discoloration compared to other coatings during natural and accelerated weathering. Moreover, these compositions exhibited the best resistance to mold growth and development of cracks.