The Effect of UV Irradiation on the Stability of Coated Fir Wood Samples

The aim of the paper consists in assessing the protection of fir wood samples against UV degradation by using polyacrylates and titanium dioxide as absorber. The irradiation was achieved for 648 hours, considered as about 2 years of weathering. Colorimetric, water absorption, and mechanical investigations were performed on samples before and after irradiation. The structural changes were evidenced by FTIR spectroscopy. Small changes in color for coated wood samples are observed after maximum 648 h of UV treatment, with the best results obtained for the specimen covered with Paraloid B72-TiO₂. Higher compressive strengths were observed for the polymer-TiO₂ coatings, in correlation with a smaller water absorption capacity of the studied samples. FTIR revealed shifted peaks with increased intensities as proof of structural changes produced by irradiation of lignin and polyacrylates. The results highlight that Paraloid B72 and Paraloid B67 mixed with TiO₂ can be used as efficient UV protective coatings for fir wood.