| Summary: | The use of TiO<sub>2</sub> nanoparticles for photoprotection comprise a side effect due to the photocatalysis of the nanoparticles under UV radiation. In this work we studied how the suppression of TiO<sub>2</sub> photocatalytic activity may affect the production of phenoxy radicals and the color of wood surfaces exposed to UV radiation. The experimental work considered the modification of TiO<sub>2</sub> nanoparticles to reduce its photoactivity and the use electron paramagnetic resonance to test free radical production. Wood samples were treated with the different TiO<sub>2</sub> nanoparticles and the radical production and color changes were evaluated after UV exposure. Experimental results showed that in wood samples exposed to UV radiation the use of TiO<sub>2</sub> with suppressed photoactivity yielded increased amounts of phenoxy radicals, in comparison to samples treated with photoactive TiO<sub>2</sub>. Similar results were obtained in terms of color change, where samples treated with suppressed photoactivity TiO<sub>2</sub> showed significantly higher color changes values, after 2000 h of UV exposure, than samples treated with photoactive TiO<sub>2</sub>. These results suggest that in wood surfaces, the photocatalytic effect of TiO<sub>2</sub> may be crucial on the performance of the nanoparticles as photoprotective treatment.
|
|---|
