influence of surface-treated nano-TiO₂ (rutile) incorporation in water-based acrylic coatings on wood protection

The aim of this research was to synthesize surface-treated nano-titanium dioxide (TiO₂) particles and incorporate them into water-based acrylic systems, which could offer long-term protection for UV-sensible wood substrates. To suppress the photocatalytic activity, the surface of TiO₂ nanoparticles in rutile crystal structure was coated with amorphous silica (SiO₂) layer. The amounts of SiO₂ were 5 and 10 wt%, respectively. Formation of SiO₂ layer on TiO₂ surface was analyzed using scanning and transmission electron microscopy. SiO₂ layer thickness increases as a function of precursor loading. In addition, the influence of SiO₂ loading on rutile UV-protective properties was determined. Transparent UV-protective coatings were developed by incorporating surface-treated nano-TiO₂ into water-based acrylic stain. The particle size distribution was determined using dynamic light-scattering measurements, which indicate that the suspension of surface-treated rutile is stable against agglomeration. Furthermore, the color change and ability of protection against UV light of coatings after nanoparticles incorporation were determined. TiO₂, surface treated with 10 wt% of SiO₂, yielded coatings of higher transparency; however, TiO₂, surface treated with 5 wt% of SiO₂, improved UV protection.