Nanomaterials in finishing of exterior wood

This paper presents the results of testing of several transparent exterior wood finishing systems with increased hydrophobic and light-stabilizing properties. The assessment of protective efficacy was based on natural exposure with evaluation of colour change and other aspects of general appearance. Contact angle measurements were done on the coated surfaces and the water vapour permeability and the liquid water permeability of coating materials were assessed. It has been established that the contact angle values do not fully express the behaviour of the surface in moist conditions. Only one of the tested materials exhibits the level of water impermeability that would enable its use for dimensionally stable wood products (such as windows and doors) where a limit for water absorption is set to 175 g/m(2).