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Nanoparticles of cerium oxide - application to coatings technologies

Fauchadour, David / Jeanson, T. / Bousseau, J.N. / Echalier, B.

The first part of this paper describes routes to customize cerium oxide nanoparticles, the aim being to make them compatible with water-based or solvent-based organic binders. The second part describes how cerium oxide nanoparticles combine the advantages of organic ultraviolet (UV) absorbers with those of mineral additives: they provide a durable UV absorption function whilst improving the hardness and strength of the organic binders. Water repellence and water barrier properties are of primary importance for the durability and the stability of wood constructions. Water absorption tests on pine panels were performed, comparing a reference to a cerium oxide colloid modified alkyd formulation (acrylic-PUD). The proper management of nanoparticles synthesis is not only key for the size control and the stability of a mineral colloid, but also to guarantee the compatibility with the organic coatings. A universal UV absorber mineral additive must be compatible and efficient with all kind of coatings used in industry. When this goal is achieved upstream, one can then beneficiate from the permanent effects of the main function of the Cerium oxide (eg UV absorbance) but also from nanoscale physical effects: scratch resistance, strength, hydrophobicity even at concentration as low as 1 wt%. These results demonstrate how nanotechnologies may contribute to the enhancement of wood construction durability and consequently fewer maintenance, without major changes for the coating industry. Thanks to its expertise in inorganic chemistry in numerous areas (Rare Earths, Silicon, Zirconium), Rhodia has regularly developed nanoparticle systems for more than ten years. Fields of application vary from tyres to cosmetics through plastics and coatings or catalysis/filtration. This know-how has recently been adapted for coatings technologies, and for organic transparent coatings in particular.