Untersuchungen zum Verhalten von mit Nanopartikeln imprägniertem Holz bei Freibewitterung

Investigation regarding the behaviour of wood impregnated with nano-particles and exposed to the open weather.

The weather resistance of Norway spruce and beech wood has been tested following coating with various nano-scale hydrophobising compounds, and has been compared with reference samples that were coated with a standard varnish. The impregnation of the timber was carried out by brush coating or a pressure process. The test results focused on changes in colorimetric values, wetting angle, timber moisture and the overall appearance. All materials and types of coating were subject to a greying of colour after a short while. The standard varnish showed the least discoloration. This tendency was also reflected in the colorimetric measurements. The wetting edge angle increasingly reduced, indicating that the hydrophobising effect was also reducing. With the standard varnish, this effect was clearly less pronounced. Overall, the tests showed that it had not been possible to inject the timber sufficiently deeply with the impregnation compound, and fix it, with either the brush or pressure impregnation method. This confirms the findings obtained in fluid retention co-efficient tests which were reported in previous articles.