ZnO-Based UV Nanocomposites for Wood Coatings in Outdoor Applications

Nanocomposite UV coatings with adjustable properties for use on wood substrates in outdoor conditions were developed. Nanoscale ZnO was shown to be an efficient light absorber. Coatings were characterized in terms of elongation at brake, residual PI and double bond conversion, universal hardness, transparency, hydrophobicity, and yellowing. Coated samples were artificially weathered and studied with regard to their optical and mechanical properties, as well as to changes in brightness, transparency, hydrophobicity, and water permeability. The prepared wood coatings showed an increased weather fastness and improved optical properties. The suitability for use in outdoor conditions was assured by optimizing the elasticity of the coating and decreasing its water permeability. The development of transparent wood coatings for outdoor conditions is an ambitious research area due to the special nature of wood. Its answers to climate changes or sunlight resemble a living organism. A wood coating must accompany huge geometrical changes and however provide sufficient protective effect against UV irradiation, water, and mechanical impact. Careful selection of basic materials and use of nanotechnology help to create systems with a good performance.