Preparation of TiO₂@ZrO₂@AlOOH@Polymethyl Acrylic Acid Nanocomposites and the Impact of Layer Structure on Color Scheme, Photocatalytic Activity, and Dispersion Stability

Abstract

Triple zirconia/boehmite/polymethyl acrylic acid layer-coated pigmentary rutile TiO 2 nanocomposites were prepared by successive hydrolysis of zirconium sulfate and sodium meta-aluminate and in situ polymerization of methyl acrylic acid in aqueous solutions. Uniform, compact, and islandlike hydrous zirconia layers could be controllably coated on rutile TiO 2 particles by adjusting the hydrolysis pH value. At a 1 wt % alumina loading, boehmite nanoparticles were deposited on the zirconia-coating layer to form an islandlike boehmite-coating layer, whereas at a 2 wt % alumina loading, in addition to the islandlike boehmite coating layer, a flocculent boehmite layer was deposited. The zirconia and boehmite layers anchored at their substrates through Zr− O−Ti and Al−O−Zr bonding, respectively. The zirconia-coating layer obviously improved the whiteness and brightness of the pigmentary rutile TiO 2 powder. The binary zirconia/boehmite layers completely suppressed the photocatalytic activity of the rutile TiO 2 powder under UV light irradiation. The boehmite layers with a large amount of OH groups caused the aggregation of TiO 2 @ZrO 2 @AlOOH nanocomposites. Anchoring polymethyl acrylic acid molecules at the TiO 2 @ZrO 2 @AlOOH nanocomposite improved its dispersion stability in water. The as-prepared TiO 2 @ZrO 2 @AlOOH@MAA nanocomposite (where MAA is polymethyl acrylic acid) can be used as a white pigment in water-based-coating materials.

Ultrastable Waterborne Nanocomposite Coating of Polyurethane and Zirconia Nanoparticles To Avoid Rainbow Effect on Polyester-Based Superficial Hardening Films

“…One method is to adjust the crystallinity and mechanical properties of polyester substrate through the biaxially stretching process which has problems such as poor process controllability, uneven particle dispersion, and poor batch stability. − Alternatively, by adding a functional layer with a specific refractive index between the polyester base layer and the HC, that is, primer, the material can meet the conditions of interference cancellation of reflected lights to achieve the goal of suppressing the appearance of rainbow patterns. , Waterborne polyurethane (WPU) is a good candidate as the coating layer in various applications. − However, the optical characteristics of pure polyurethane cannot meet the requirements as an optical coating layer to avoid the rainbow effect on polyester films. Organic–inorganic nanocomposites have a wide range of applications in various fields, which can improve the mechanical properties, electrical properties, and optical properties of the materials. − Transparent nanocomposite films with tunable RI values have been developed by adding inorganic components such as ZrO 2 nanoparticles − and TiO 2 nanoparticles , into organic polymer matrix. The dispersion state of functional nanoparticles in the emulsion is the key to the creation of high-quality WPU coating films with desired optical performances, − while the aggregation of the particles will cause the scratch on the surface of the polymer substrate and the appearance of bubbles around the particles in the process of stretching into film, resulting in uneven thickness and low visible light transmission. − …”

Facile synthesis of nanostrip-structured pseudo-boehmite “nest” for nano-TiO2/γ-Al2O3 construction to remove tetracycline hydrochloride in water

“…Among them, TiO 2 has attracted large attention due to its strong oxidation capacity and high chemical stability [26]. However, its poor adsorption capacity and very limited visible light degradation efficiency (only ultraviolet rays can be absorbed) restrict its application ranges, which significantly can be improved by the introduction of PB or γ-Al 2 O 3 [25,27]. Therefore, various composites of TiO 2 -PB or TiO 2 -Al 2 O 3 were synthesized for photocatalytic applications and widely employed for the removal of pollutants in water systems [28][29][30][31].…”

Fabrication of SiO2/Al2O3 Composite-Coated TiO2 by Pulsed Chemical Vapor Deposition and Its Applications

“…It has also been reported that Al 2 O 3 can inhibit photocatalytic activity, improve whiteness and brightness, and the alumina loading affects the relative light scattering . The organic layer has normally been used to improve the pigmentary property, especially for dispersibility . The improvement of infrared reflectance and visible reflectance has been observed in polymer-coated TiO 2 . , The SiO 2 /Al 2 O 3 composite film can improve the brightness and whiteness of TiO 2 pigments but accompanied by a reduced relative scattering index caused by Al 2 O 3 .…”