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  • Polyhedral oligomeric silesquioxanes as titanium dioxide surface modifiers fortransparent acrylic UV blocking hybrid coating
    Godnjavec, Jerneja, 1981 ...
    Architectural coatings are usually recommended to enhance the durability of wood in exterior environment. Inorganic UV absorbers are often used to prolong the polymer stability in coatings ... formulation since they offer the most effective UV protection in the long term since they do not decompose and do not migrate in coating during weathering [1]. In the recent years, the preparation of polymer nanocomposite materials has been intensely considered due to their relatively remarkable various properties. Titanium dioxide (TiO2)enjoy manifold applications that include their usage as white pigment in the paint, plastic, and paper industries however it's nanoparticles in rutile crystal form have a special function as an inorganic UV shielding material. Currently, the requirement for optical materials with high refractive index and transparency in the fields of optical waveguides, antireflection coatings, adhesives for optical components and in our case especially for outdoor clear coating is increasing markedly. Significant properties of coatings with nano rutile particles are sufficient transparency and high absorption of UV light what can be achieved with nanoparticles of appropriate size and shape, narrow size distribution and excellent dispersability. To achieve proper dispersion of nano-particles into the polymer matrix and to yield a better compatibility between the nano-particles and host polymeric materials, the use of different inorganic/organic post treatments for surface modification of nano-particles is recommended. The appropriate surface modification of nanoparticles also by formation of chemical and physical interactions with polymer matrix could guarantee a durable chemical junction between two incompatible phases. In order to improve dispersability of nano-particles in polymeric materials, surface modification of TiO2 nano-particles in a polyacrylic clear coating were investigated. First, TiO2 nano-particle's surface was modified with inorganic oxide in order to reduce nanoparticles agglomeration, to enhance photochemicalstability and finally to improve TiO2 dispersability. Second, Polyhedral Oligomeric Silsesquioxane (POSS) molecules were used to additionally enhance the dispersion homogeneity of nanosized TiO2. in rutile crystale form in acrylic water based transparent coating. POSS nanostructures provide a unique approach to the development of polymeric nanoengineered materials. POSS molecules are cage like organic-inorganic structures describedby the general chemical structure RSiO1,5. Nanoparticle shape, size and microstructural analysis was done by analytical electron microscopy (AEM) while particle size distribution was performed by DLS technique. The grafting of POSS-molecules on the nano-particles surface was characterized with TGA andFTIR techniques. The stability of TiO2 rutile nanoparticles in an acrylic clear coating was evaluated by zeta potential measurement. Improved performance of grafted nano TiO2 with inorganic and POSS surface treatment in nanocomposite coatings was demonstrated trough UV-VIS spectroscopy and accelerated weathering.
    Vir: 7th Coatings Science International 2011 : COSI 2011 : book of abstracts : Hotels van Oranje Noordwijk, 27 June-1 July 2011, The Netherlands (Str. 62)
    Vrsta gradiva - prispevek na konferenci
    Leto - 2011
    Jezik - angleški
    COBISS.SI-ID - 35226373

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