Effect of addition of nanosized UV absorbers on the physico-mechanical and thermal properties of an exterior waterborne stain for wood

Effect of silane modified nano ZnO on UV degradation of polyurethane coatings

“…Zinc oxide is an inorganic UV absorber having a wide band gap energy and used as UV stabilizer in organic coatings [1][2][3][4]. The nano ZnO was investigated as UV absorber in a polyurethane/acrylic clear topcoat.…”

“…The influence of ZnO concentration and film thickness on the UV protection was investigated and the results show that the presence of nano ZnO at 2.0 g/m 2 can block more than 99% UV radiation [1]. The nano ZnO and silica-coated nano ZnO improved the exterior durability and physic-mechanical properties of the acrylic waterborne coatings for wood [2,3]. The presence of nano zinc oxide particles reduces the photo-degradation of the aromatic polyurethane coating [4].…”

Investigating the effects of weathering on wood coatings

“…The protection mechanism of HALS, which is not related to ultraviolet absorption but to "quenching" of excited states, according to the Denisov cycle [20], is efficient on the surface layer of the coating films, where it limits the growth of free radicals by trapping them (v-shaped signs in Figure 4) and avoiding the prosecution of the degradation process. Therefore HALS is necessary to inhibit the photo-oxidation on the surface.…”

Nanostructured materials for protection and reinforcement of timber structures: A review and future challenges

“…Recent research has examined the photochemical stability of water-based acrylic paints containing anatase and rutile nano-titania [21]. Research carried out to investigate the properties of nano-coatings using zinc oxide, silica, alumina and titanium dioxide active nano-particles dispersed in acrylic-based, waterborne, solid-colour stains for exterior wood [22][23][24] found significant improvement in UV-shielding of the nanocomposites coatings demonstrated through accelerated weathering. Main fields of application of nano-based coatings addressed to wood already present on the market: waterproofing (Clay, SiO 2 , CeO 2 , TiO 2 ); UV protection (TiO 2 , ZnO, SiO 2 , CeO 2 , Fe 2 O 3 , clays); biotic decay protection (Ag, ZnO, Cu); fire resistance (SiO 2 , Clay, TiO 2 ); self-cleaning/photocatalitic (TiO 2 , ZnO); anti-scratching, hardness (TiO 2 , Al 2 O 3 , SiO 2 , clays, lime) (from [14]).…”