Determination of uv resistance of different wood species in outdoor conditions

The aim of this study is to determine the natural resistance of 16 different wood species that has industrial importance against the effects of degrading factors, especially UV rays, by using artificial and real field experiments. In addition, modeling was created between artificial aging tests and real field trials to determine the how many hours of artificial aging test was equal to how many months / years in natural conditions. For this purpose, walnut, ash, cherry, oak, maple, teak, mazel, beli, limba, anigre, tulipe, sapele, american walnut, eucalyptus, beech and pine samples were exposed to 340 nm UVA lamps in the laboratory for 1512 hours. Samples were also exposed to the degredation agents of Bursa outdoor conditions for 1 year. The results of artificial aging test showed that all samples had negative ΔL* values except for teak and american walnut samples. First hours of aging test was effective on color change of samples. The maximum darkening and total color change was measured on the tulipe samples whilst the minimum color change was observed on beli samples during the 1512 hours. In the natural aging test, pine samples had the highest darkening and color change values whilst the least change was obtained within american walnut samples. In general, two againg test caused a loss in glossiness and an increase in surface roughness of samples along with the test period. FTIR analysis clearly showed that the degradation on the wood components was occured in the first hours, and lignin completely disappeared after 168 hours and 153 days for artificial aging and natural againg test, respectively. Regression models of two aging tests showed that ash, beech, maple, cherry, oak, pine, mazel, american walnut, tulipe and anigre samples had high R2 values. Eucalyptus, walnut, limba, teak and beli samples had moderate R2 values whilst sapeli had the low R2 values.