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Considering the significant production volume of wood composite materials, the search for ecological solutions to reduce formaldehyde emissions during their pressing and further operation is urgent. The effect of nanoparticles of zinc, aluminium, and iron metals on formaldehyde emission from particleboard samples during their manufacture and subsequent exposure for three weeks is examined in the paper. Nanoparticles of metals were produced by the electro-spark method. In order to determine the priority metal, the method of analysis of hierarchies and search experiments was used. Samples of particleboard were made with the addition of a modified glue based on UF resin. Nanoparticles of the metals Zn, Al, and Fe were used in concentrations of 2% and 8%, respectively, to modify the adhesive resin. Measurements of the level of free formaldehyde were carried out on the third and seventeenth days after the pressing of particleboard samples. The results of experimental studies confirmed the theoretical calculation of priority based on the selected assessment criteria. The best results were observed when zinc was used as a filler at a concentration of 8%. [ABSTRACT FROM AUTHOR]

The oil palm plantations in Indonesia have prompted the need for technology to utilize nonproductive oil palm trees (Elaeis guineensis Jacq.). This study was aimed to collect information on the quality of oil palm trunk veneer modified using SRF impregnation from oil palm bark extract. The impregnant was synthesized by copolymerizing resorcinol (R) and formaldehyde (F) on palm bark extract (S). Fourier Transform Infrared (FTIR), PyrolysisGas Chromatography-Mass Spectroscopy (Py-GCMS), X-Ray Diffraction (XRD), and Differential Scanning Calorimetry (DSC) were used to characterize the oil palm resorcinol formaldehyde (SRF) resin. The SRF-impregnant material was used to improve the oil palm veneer's density, thickness, swelling, stiffness, and strength. The results of the DSC analysis showed that the SRF resin was thermoset. The SRF-impregnated palm veneer could increase the veneer density by 20%, lower thickness swelling below 25%, and increase the modulus of rupture (MOR) by over 10% and modulus of elasticity (MOE) by 50%. [ABSTRACT FROM AUTHOR]

The use of polycondensation urea-formaldehyde (UF) resins in the woodworking and furniture industries is widespread due to their relatively low price, high reactivity, availability of raw materials, and ease of use. After curing, they provide a transparent, brittle joint, but their main disadvantage is the continuous emission of formaldehyde. The naturally occurring biopolymer keratin and the amino acid cysteine prepared from sheep wool were chosen and tested as possible agents for UF adhesives, allowing the reduction of formaldehyde emissions from wood-based panels. Emissions of formaldehyde were determined in accordance with EN ISO 12460-4. The gluing quality was tested according to standard EN 314-1, and the tested plywood met the requirements of standard EN 314-2. The most significant decrease in formaldehyde emission by up to 44.0% was achieved by applying 1% MOD-I (pre-condensate of glutaraldehyde and urea + cysteine) to the reference UF adhesive. Therefore, samples prepared for this study have great potential for application as environmentally friendly formaldehyde scavengers. [ABSTRACT FROM AUTHOR]

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]

The effective use of low-grade pine wood (Pinus Sylvestris L.) affected by rot, the volume of which is currently growing mainly due to climate change is proposed in the paper. Pine wood in the form of wood wool was proposed to use as an insulating filling inside the structure of wall panels. Modification of wood wool was carried out with various binders to ensure its biological stability. The experimentally verified calculation of thermal properties confirmed the proposed construction of wood panels with specified insulation, as well the wall thickness fulfils requirements according to building codes for construction engineering. The minimum thickness of the outer walls of frame wooden houses withstanding daily or seasonal temperature fluctuations was determined. [ABSTRACT FROM AUTHOR]

Industrially important properties of wood can be changed due to the modification of birch wood (Betula pendula L.) after the process of thermal treatment with saturated water steam. The birch wood was modified by saturated water steam at 125 ± 2.5 °C for 8 hours and at a pressure of 0.18 MPa. The water contact angle of steam-treated birch wood increased from 42.1° (for untreated birch wood) to 52.4° (for steam-treated birch wood), and the stability of water drop on steam-treated birch wood surface increased. FTIR spectra showed an increase in C=O and glycoside bonds concentration on the surface of steam-treated birch wood, but the concentration of C-O-C groups decreased. XPS measurements confirmed that the concentration of oxygen as well as C=O and C-O-O groups on the surface of steamtreated birch wood showed an increment in comparison with the native wood sample. SEM micro photos confirmed the minor changes of birch wood cells due to the action of saturated water steam modification. [ABSTRACT FROM AUTHOR]

The bonding of wood with assembly adhesives is crucial for manufacturing wood composites, such as solid wood panels, glulam, furniture parts, and sport and musical instruments. This work investigates 13 hardwoods—bangkirai, beech, black locust, bubinga, ipé, iroko, maçaranduba, meranti, oak, palisander, sapelli, wengé and zebrano—and analyzes the impact of their selected structural and physical characteristics (e.g., the density, cold water extract, pH value, roughness, and wettability) on the adhesion strength with the polyvinyl acetate (PVAc) adhesive Multibond SK8. The adhesion strength of the bonded hardwoods, determined by the standard EN 205, ranged in the dry state from 9.5 MPa to 17.2 MPa, from 0.6 MPa to 2.6 MPa in the wet state, and from 8.5 MPa to 19.2 MPa in the reconditioned state. The adhesion strength in the dry state of the bonded hardwoods was not influenced by their cold water extracts, pH values, or roughness parallel with the grain. On the contrary, the adhesion strength was significantly with positive tendency influenced by their higher densities, lower roughness parameters perpendicular to the grain, and lower water contact angles. [ABSTRACT FROM AUTHOR]

In this study, the physical and mechanical properties of plywood panels made from pre-compressed birch (Betula verrucosa Ehrh.) veneer were evaluated. Veneer sheets underwent short-term thermo-mechanical (STTM) compression at temperatures of 150 or 180 °C and at pressures of 0.5, 1.0, 1.5, 2.0, 2.5, 3.0 or 3.5 MPa for a period of 1 min prior to adhesive being applied and pressed into panels using phenol formaldehyde adhesive at 100 g/m2 spread rate; this was one-third less than the adhesive spread used for the control panels (150 g/m2). The pressing pressure was 1.0 MPa, which was almost half of the pressure used for the control panels (1.8 MPa); and pressing time was 3 min, also half of the pressing time used for the control panels (6 min). The results showed that surface roughness of compressed veneer, water absorption and thickness swelling of plywood panels made from compressed veneer were significantly improved. The shear strength values of plywood panels made from compressed birch veneer even with reduced adhesive spread were higher than those of plywood panels made from uncompressed veneer. The findings in this study indicated that compression of birch veneer could be considered as an alternative to produce more eco-friendly (owing to smaller adhesive spread) value-added material with enhanced properties. [ABSTRACT FROM AUTHOR]