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A comparative analysis of the quality properties of coating materials based on linseed oil and alkyd film formers is provided in the paper. The advantages and disadvantages of linseed oil-based and alkyd-based coating materials are explored. Protective materials such as alkyd coating material for wood and drying linseed oil were applied on the compared pine-wood samples. The authors determined the drying time of linseed oil and alkyd coating materials on pine wood, the thickness of the dry film, heat resistance, lightfastness, as well as water resistance of protective and decorative coatings. Linseed oil-based coating materials form thin-layer coatings on the surface of wood, unlike coatings based on alkyd materials. Alkyd coating materials transitioned into a solid state faster than the linseed oil-based ones. Coatings based on linseed oil have a higher moisture resistance. Higher indicators of heat resistance were observed in coatings based on linseed oil materials. [ABSTRACT FROM AUTHOR]

Ukrainian companies mainly use birch in the manufacture of plywood, but species, such as black alder, are not yet widely used in the manufacture of plywood due to their poorer properties. It is well known that thermal compression is often used to improve the properties of solid wood. Good lay-up schemes of veneer can maximize the advantages and minimize the disadvantages of these wood species, and generally improve the utility value of the plywood. This research aimed to develop plywood panels with two wood species and two types of veneer treatments in order to evaluate the influences of different lay-up schemes on the properties of the plywood. Five-layer plywood panels were formed with 16 different lay-up schemes using birch (Betula verrucosa Ehrh.) (B) and black alder (Alnus glutinosa L.) (A) veneers, which were non-densified (N) and thermally densified (D). The different lay-up schemes were used to identify opportunities to improve the mechanical and physical properties of the plywood by replacing the birch veneer in the plywood structure with an alternative alder veneer. The veneer sheets were thermally densified in a laboratory hot press at a temperature of 180 °C and pressure of 2 MPa for 3 min. The conducted study showed that the bending strength, modulus of elasticity and shear strength of mixed-species plywood (BD–AN–AN–AN–BD) increased by up to 31.5%, 34.4% and 16.8%, respectively, in comparison to those properties of alder plywood from non-densified veneer (AN–AN–AN–AN–AN), by positioning alder non-densified veneers in the core layers and birch densified veneers in the outer layers. Moreover, the surface roughness of plywood panels with outer layers of birch veneer was lower than that of panels with outer layers of alder veneer. It was shown that non-treated alder veneer, despite exhibiting somewhat lower strength properties than birch veneer, could be successfully used with proper lay-up schemes in the veneer-based products industry. [ABSTRACT FROM AUTHOR]

The aim of this study was to improve the properties of lightweight particleboards by their veneering. The industrially produced wood particles, rotary-cut birch veneer, expanded polystyrene (EPS) granules and urea-formaldehyde (UF) resin were used to manufacture non-veneered and veneered boards in laboratory conditions. The boards were manufactured with different densities of 350, 450 and 550 kg/m3 and with various levels of EPS content 4, 7 and 10%. Boards without EPS granules as the reference were also manufactured. Bending strength (MOR), modulus of elasticity in bending (MOE), internal bond (IB) strength, thickness swelling (TS) and water absorption (WA) of lightweight particleboards were determined. This study confirmed that veneering of lightweight particleboards by birch veneer improved mechanical properties significantly. The MOR and MOE of veneered boards throughout the whole density range of 350–550 kg/m3 meet the requirements of the CEN/TS 16368 for lightweight particleboards types LP1 and LP2. The IB strength of veneered boards only with density of 550 kg/m3 meets the requirements of CEN/TS 16368 (type LP1). The MOR, MOE and IB of non-veneered boards also meet the requirements of CEN/TS 16368 (type LP1) except boards with density of 350 kg/m3 for MOR and MOE, and except densities of 350 and 450 kg/m3 for IB. [ABSTRACT FROM AUTHOR]

An investigation was made of wood of the species oak (Quercus petraea), beech (Fagus sylvatica L.), maple (Acer pseudoplatanus) and ash (Fraxinus excelsior) pre-treated using radio-frequency (RF) plasma in air at reduced pressure. Physical and chemical changes for all of the wood species were determined using measurements of water contact angles and FTIR-ATR spectroscopy. The results confirmed an increase in the wood’s hydrophilicity/polarity in all cases, caused by an increase in –OH group concentration due to irradiation by RF plasma. The content of oxygen-containing functional groups after treatment by RF plasma significantly increased, and the water contact angles were diminished. FTIR-ATR spectroscopy confirmed that RF plasma modification of the surfaces of all investigated wood samples led to certain changes, which were also dependent on the time of plasma exposure. [ABSTRACT FROM AUTHOR]

In this study we assessed the efficacy of manufacturing lightweight particleboards using sunflower (Helianthus annuus L.) stalk particles. Three-layer lightweight particleboards with target densities of 350, 450 and 550 kg/m3 were produced with different proportions of wood-to-sunflower stalk particles (100:0%, 75:25%, 50:50%, 25:75%, 0:100%) in the core layer. The outer layers consisted only of wood particles. The boards made entirely with wood particles in the outer and core layers were reference boards. Conventional urea-formaldehyde (UF) resin was used to bond the particles. It was found that the replacement of wood particles in the core layer with sunflower stalk particles led to an improvement in the physical and mechanical properties of lightweight UF-bonded particleboards. Three-layer boards with the optimum combination of 100% wood particles in the outer layers and 100% sunflower stalk particles in the core layer had slightly higher bending strength (MOR) and modulus of elasticity (MOE) than boards made entirely from 100% wood particles, but much greater internal bonding strength (IB), lower water absorption (WA) and less thickness swelling (TS) at the same board density. The MOR, MOE and IB values for 550 kg/m3 boards containing 100% sunflower particles in the core layer were higher than the reference boards by 16.3%, 16.6% and 62.7%, respectively. The MOR, MOE and IB of lightweight particleboards with densities of 450 and 550 kg/m3 made with 100% sunflower particles in the core layer fully complied with the CEN/TS 16368 standard for both types of board, LP1 and LP2. Substitution of wood particles with sunflower stalk particles did not cause negative changes in the formaldehyde content of the boards. • The possibility of making lightweight PBs from SSP was confirmed. • Including SSP in the core layer improves the IB strength of boards. • Including SSP in the core layer decreases the WA and TS of boards. • Lightweight PBs from SSP meet the requirements of CEN/TS 16368. • Using of SSP in the manufacture of PBs saves wood raw materials. [ABSTRACT FROM AUTHOR]

Low-temperature plasma was used to improve the surface and adhesive properties of wood. The pre-treatment of wood surfaces using radio-frequency (RF) discharge plasma is attractive for various wood applications, mainly because of the high efficiency and low production cost of the process. In addition, a significant increase in the polar component of the wood surface energy, which is associated with the presence of acid–base interactions (electron donor–acceptor bonds), after modification by RF discharge plasma was identified. The treatment of wood by RF plasma exhibited an aging effect, with the modified surface never recovering its initial hydrophobic state. Indeed, the enhancement of the wettability of wood is necessary for promoting better adhesion with water-based adhesives and coatings, which is currently the subject of ongoing study. [ABSTRACT FROM AUTHOR]