Increasing the Strength of the Glue Line in the Production of Thermally Modified Wood Paneling

This work is devoted to the study of the effect of ultraviolet rays for the surface activation of pine wood thermally modified at temperatures of 180−240 °C in order to increase the surface roughness, enhance the wettability of thermal wood and the adhesive strength of the glue in the production of wood block furniture panels. Studies were carried out to measure the contact angle of wettability of thermally modified wood samples of pine, as a result of which it was determined that the ultraviolet treatment process contributes to an increase in the adhesion properties of the surface layer of thermally modified wood by more than 13% due to the reactivity of ultraviolet rays to oxidize and degrade ligno-containing wood products. At the same time, the most active process of surface activation takes place during 60 min of ultraviolet irradiation of wood with a total irradiation of at least 125 W/cm2. It was revealed that the combined effect of two-stage wood processing, including preliminary volumetric thermal modification followed by surface ultraviolet treatment, causes an increase in the moisture resistance of glued wood products by 24%. So, if the strength of the glue seam when gluing natural wood samples after boiling decreased by 46%, then the samples that underwent two-stage processing showed a decrease only by 22%. In connection with the results obtained, an improved technology for the production of furniture boards for the manufacture of moisture-resistant wood products is proposed.