THE INFLUENCE OF MOISTURE CONTENT OF SELECTED WOOD SPECIES ON HYDROPHOBICITY

V zadnjem obdobju številne raziskave potrjujejo, da je življenjska doba lesa na prostem odvisna tudi od sposobnosti lesa da ostane suh. To pomeni, da se les med padavinskimi dogodki ne navlaži, če pa se, se les tudi hitro posuši. V raziskavi smo se osredotočili na teste, ki osvetljujejo vodoodbojnost in kratkotrajno navzemanje vode v les, ki se že uporabljajo za vrednotenje odpornosti lesa proti navlaževanju. Uporabili smo 22 različnih materialov, ki so vgrajeni na modelnem objektu Oddelka za lesarstvo. Del materialov je bilo termično modificiranih, del obdelan z voski in del impregniran z baker etanolaminskim pripravkom. Polovico vzorcev smo umetno pospešeno postarali v skladu s standardom SIST EN 84. Uravnovesili smo jih pri različnih relativnih zračnih vlažnostih in določili lesno vlažnost, kontaktni kot in kratkotrajno navzemanje vode, sledila je še analiza korelacije med rezultati. Ugotovili smo, da lesna vlažnost, različna zaščita ter modifikacija vplivajo na vpijanje vode v les ter prav tako na vodoodbojnost. Kontaktni koti vode se pri staranih vzorcih glede na različno lesno vlažnost ne razlikujejo toliko kot pri nestaranih vzorcih. Najtesnejšo korelacijo med rezultati smo določili pri termično modificiranih vzorcih.In the recent period, many studies have confirmed that the service life of wood in outdoor applications depends on inherent durability and the ability of the wood to remain dry. This means that the wood does not get wet during rain events, however if it does, wood should dry out quickly. In the respective study, we focused on tests that highlight wood water-relations, predominately short-term absorption of water, and contact angles of water on wood. These tests are used already to evaluate the water performance of wood. We used 22 different materials that were installed on the model object of the Department of Wood Science and Technology. One part of the materials was thermally modified, the part treated with waxes and the part impregnated with copper ethanolamine preservatives. Half of the samples were artificially aged according to the SIST EN 84 standard. We exposed the samples to different relative air humilities and determined wood moisture, contact angles and short-term absorption of water. In addition, correlation between the results was performed. We have confirmed that the water performance of wood with different moisture content is not uniform, and it depends on applied biocides, modification and other treatments... The contact angles of the water on the aged samples are different in comparison with those on the non-aged samples depending on the different wood moisture content. Thermally modified samples exhibited the best correlation between the obtained results