WOOD RESEARCH Volume 70, Number 3, 2025
IRYNA LYTVYN, NATALIYA BEKHTA, IRYNA KUSNIAK, PAVLO BEKHTA, and JÁN SEDLIAČIK

Properties of Particleboards with Partial Replacement of MUF Resin by Sodium and Magnesium Lignosulfonates

The objective of this study was to evaluate the feasibility of partially replacing melamine-urea-formaldehyde (MUF) resin with lignosulfonates and to assess the effects on the physical and mechanical properties of the boards. Particleboards were produced using MUF resin, with partial substitution by either sodium lignosulfonate (NaLS) or magnesium lignosulfonate (MgLS) at levels of 10%, 20%, and 30% by weight. Control boards were also manufactured using 100% MUF resin for comparison. The results demonstrated that both, the type and proportion of lignosulfonate, significantly influenced the physical and mechanical characteristics of the boards. Specifically, the lignosulfonate content had a notable negative effect on the internal bond (IB) strength, bending strength (MOR), and thickness swelling (TS). In contrast, the type of lignosulfonate significantly affected only the IB strength. Boards containing 10% NaLS exhibited comparable properties to those of the control group. Additionally, boards incorporating NaLS generally outperformed those containing MgLS, although the differences were not statistically significant. Particleboards incorporating with 10% or 20% NaLS or MgLS, although exhibiting lower IB strength, MOR and modulus of elasticity (MOE) than the control boards, met the performance criteria for type P2 boards, intended for interior applications (including furniture) in dry conditions, as specified by the EN 312.

WOOD RESEARCH Volume 70, Number 2, 2025
JÁN SEDLIAČIK, PAVLO BEKHTA, IGOR NOVÁK, ANGELA KLEINOVÁ, MATEJ MIČUŠÍK, JÁN MATYAŠOVSKÝ, and PETER JURKOVIČ

SURFACE PROPERTIES OF HYDRO-THERMALLY MODIFIED BEECH WOOD AFTER RADIO-FREQUENCY DISCHARGE PLASMA TREATMENT

Heat treatment is widely used to improve the properties of wood, in particular its color. However, this treatment causes changes in the surface properties of wood, the surface becomes hydrophobic, which can cause serious problems when gluing or coating. In this study, the radio-frequency discharge (RFD) plasma was used to increase the hydrophilicity of the steam-modified beech (Fagus sylvatica L.) wood due to the formation of various polar groups (e.g., hydroxyl, carbonyl, carboxyl, etc.). The increased surface polarity improves the wettability and hydrophilicity due to oxidation reactions. Tensile shear strength properties of lap joints were processed according to EN 205. Plasma-treated samples showed higher strength when compared to plasma-non treated samples after the D4 test according to EN 204

WOOD RESEARCH Volume 65, Number 6, 2020
IGOR NOVÁK, ANGELA KLEINOVÁ, Ivica Janigová, MATEJ MIČUŠÍK, JÁN SEDLIAČIK, Miroslav Šlouf, PAVLO BEKHTA, JÁN MATYAŠOVSKÝ, and PETER JURKOVIČ

Properties of water steam-treated maple wood (Acer pseudoplatanus L.)

The hydrothermal treatment of maple (Acer pseudoplatanus L.) wood by steam represents the modification method with the effective heat transfer, which can improve industrially significant properties of wood, i.e. its color, hydrophobicity and subsequently dimensional stability. The maple wood was modified by steam at 125°C during 8 hours, and at pressure of 0.18 MPa. The water contact angle of steam-treated maple wood increased from 44.9° (for untreated maple wood) to 55.3° (for steam-treated maple wood), and the stability of water drop on steam-treated maple wood surface increased. FTIR spectra show an increase in C=O and glycoside bonds concentration on the surface of steam-treated maple wood, but the concentration of C-O-C groups decreased. SEM micro photos confirmed the deformation and shrinking of maple wood cells due to steam treatment. XPS measurements confirmed, that the concentration of oxygen as well as C=O and C-O-O groups on the surface of steam-treated maple wood showed a slight decrease in comparison with pristine wood sample.