Influence of FE-DBD plasma treatment on the wettability of wood

V diplomskem delu smo analizirali površino bukovega (Fagus sylvatica L.) in smrekovega (Picea abies (L.) Karst.) lesa, po obdelavi z dielektrično barierno razelektritveno (DBD) plazmo s plavajočo elektrodo. Znano je, da na učinek obdelave površin lesa s plazmo vplivajo zunanji (lastnosti materiala in plina, dimenzije elektrod in reaktorja, električna moč, čas tretiranja itd.) in notranji (lastnosti plazme) dejavniki. Pojav plazme smo posneli s fotokamero in analizirali z računalniškim programom. Z določanjem stičnih kotov vode na obdelanih in neobdelanih površinah lesa smo preučili vpliv spreminjanja zunanjih parametrov naprave na omočljivost lesa. Zunanji parametri, ki smo jih spreminjali, so bili podajalna hitrost, razdalja med dielektrikoma (RME) in oddaljenost površine lesa od dielektrikov (RMES). Z vrstičnim elektronskim mikroskopom smo opazovali strukturo in topografijo površin vzorcev. Izmerjene sive vrednosti analiziranih razelektritev pri obdelavi lesa bukve so bile višje kot pri obdelavi lesa smreke. Rezultati so pokazali, da se stični kot kapljic vode zmanjša z zniževanjem podajalne hitrosti. Površino smrekovega lesa voda bolje omaka pri RMES 0,5 mm, pri bukovini pa pri 1 mm. Optimalna razdalja pri smrekovem vzorcu med elektrodama je 8 mm, pri bukovem pa so najboljši rezultati pri 10 mm.In this thesis, we analysed the surface of beech (Fagus sylvatica L.) and spruce (Picea abies (L.) Karst.) wood after treatment with dielectric barrier discharge (DBD) plasma with a floating electrode. It is known that the effects of plasma treatment of wood surfaces are influenced by external (material and gas properties, electrode and reactor dimensions, electrical power, treatment time, etc.) and internal (plasma properties) factors. Plasma appearance was recorded with a camera and analysed using a computer program. By determining the contact angles of water on treated and untreated wood surfaces, the effect of changing the external parameters of the device on the wettability of wood was examined. The external parameters we varied were the speed of samples, the distance between the dielectrics (RME) and the distance between the wood surface and the dielectrics (RMES). Using the scanning electron microscope, the structure and topography of the sample surfaces were observed. The measured grey values of analysed discharge in the treatment of beech wood were higher than in the treatment of spruce wood. The results showed that the contact angle of the water droplets decreases as the speed of samples decreases. The surface of spruce wood is better wetted with water at RMES 0.5 mm and the surface of beech wood at 1 mm. The optimum RME for the spruce specimen is 8 mm, and for the beech, the best results are at 10 mm