Abstract
The use of TiO2 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 TiO2 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 TiO2 nanoparticles to reduce its photoactivity and the use electron paramagnetic resonance to test free radical production. Wood samples were treated with the different TiO2 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 TiO2 with suppressed photoactivity yielded increased amounts of phenoxy radicals, in comparison to samples treated with photoactive TiO2. Similar results were obtained in terms of color change, where samples treated with suppressed photoactivity TiO2 showed significantly higher color changes values, after 2000 h of UV exposure, than samples treated with photoactive TiO2. These results suggest that in wood surfaces, the photocatalytic effect of TiO2 may be crucial on the performance of the nanoparticles as photoprotective treatment.
Highlights
The use of TiO2 nanoparticles (NP) has resulted in important technological advances for material protection
We focused our attention on the photoactivity of TiO2 nanoparticles as a factor that may influence its performance as photoprotective treatment for wood surfaces
The photocatalytic effect of TiO2 NP has documented in polymeric materials, in which the use TiO2 NP with suppressed photocatalytic activity been well documented in polymeric materials, in which the use TiO2 NP with suppressed has resulted in improved photoprotection and increased lifetime of the product [3]
Summary
The use of TiO2 nanoparticles (NP) has resulted in important technological advances for material protection. In wood surfaces, which are highly susceptible to photodegradation, the use of TiO2 NP is effective at reducing color changes due to photodegradation when applied directly onto the surface or in combination with coating systems [1,2]. UV radiation can break down carbon–carbon, carbon–oxygen and carbon–hydrogen bonds present in the different polymers that form part of wood, inducing undesirable color changes due to photo-oxidative reactions [4]. At nano-scale, the absorption of UV radiation by TiO2 comprises a complex process in which highly reactive radical species are produced in the presence of oxygen and water [5,6,7,8,9].
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
