Modification of wood was carried out with Meldur-DMES in a combination with a thermal modification, so as the resistance of modified wood to blue fungi was analysed. The samples were prepared from the sapwood of a pine tree (Pinus sylvestris) and from the sapwood of a spruce (Picea abies) according to the SIST EN 152 standard. They were modified in a vacuum-chamber at different Meldur concentrations (5 % and 10 % solution) with and without a catalyst. The modified samples were washed out according to the SIST EN 84 standard before their exposal to fungi. The test was carried out according to the SIST EN 152 standard with 2 fungi, Aureobasidium pullulans and Sclerophoma pithyophila. After being exposed for 6 weeks, the portions of the surfaces turned blue were defined. It was found out that the higher level of resistance of wood to the blue fungi was achieved at a higher concentration of Meldur, 10 % solution with the addition of a catalyst and at higher temperature (170 °C). The exceptions are the samples of a spruce tree, modified at temperature of 170 °C, which achieved a complete resistance to the colouring with the blue fungi.
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