WOOD RESEARCH Volume 70, Number 3, 2025
Holta Çota, ENTELA LATO, DOKLEA QUKU, HEKTOR THOMA, and ERALD KOLA

The Effect of Heat Treatment on Compression Strength of Silver fir (Abies alba Mill.) and Ash Wood (Fraxinus angustifolia Vahl.). Short notes

This study investigates the effects of thermal modification on the compressive strength parallel to the grain of ash (Fraxinus angustifoglia Vahl.) and fir (Abies alba Mill.) wood. Specimens were thermally treated at 130°C, 180°C, and 220°C for durations of 2 and 8 h under atmospheric conditions. Mass loss increased with both temperature and time, with fir exhibiting greater loss than ash, up to 20.3% and 15.7%, respectively, at 220°C for 8 h. Compressive strength was influenced significantly by treatment intensity. Fir showed minor improvements at lower temperatures but experienced a reduction of up to 23.0% at the highest treatment. In contrast, ash displayed enhanced strength at 180°C (up to +15.1 %) and retained better mechanical performance at 220°C, with a maximum reduction of 11.3%. These findings demonstrate that heat treatment can both enhance and deteriorate compressive strength depending on the treatment severity, emphasizing the need to optimize thermal parameters for maintaining structural performance in wood applications.

WOOD RESEARCH Volume 69, Number 3, 2024
PATRIK MITRENGA, LINDA MAKOVICKÁ OSVALDOVÁ, MIROSLAVA VANDLÍČKOVÁ, and MILAN KONÁRIK

OPTIMIZING THE AMOUNT OF FLAME RETARDANT USED FOR SPRUCE WOOD

The study investigated the effect of the amount of selected retardant coatings produced and used in the Slovak Republic on the fire resistance of spruce wood samples. Experiments were conducted for two different types of flame retardants: intumescent flame retardant (IFR) and inorganic salt-based flame retardant (IS). Based on different amounts of coating applied to spruce wood samples, the important parameters as mass loss, mass loss rate and fire spread rate were determined. The experiment consisted of applying a flame source to the samples at an angle of 45° and monitoring the mass of the samples during the experiment. The findings show that when IFR is used, the protection effect of the wooden samples increases linearly with the amount of coating. However, for the samples on which an IS flame retardant was applied, a higher amount of coating had no effect on increasing the fire resistance of the wood. In this case, the average total mass loss was the same regardless of the amount of coating, yet a significant retardation effect was observed compared to the untreated samples. Samples treated with IFR showed a lower total mass loss and also a significantly lower maximum mass loss rate compared to the samples with applied IS flame retardant

WOOD RESEARCH Volume 66, Number 1, 2021
Juraj Jancík, Linda Makovická Osvaldová, and Frank Markert

Thermogravimetric analysis, differential scanning calorimetry and time-to-ignition of wood materials treated with water glass flame retardants

The paper investigates efficiency of silicate flame retardants on wooden fibres (used for production of medium-density fibreboards) and spruce boards. A simultaneous thermal analysis and cone calorimetry were used for the assessment. Specimens were treated with three different types of silicate water glass: sodium silicate, potassium silicate and modified silicate. Along with these, one sample of untreated fibres was tested in order to provide a baseline sample. As a result of the simultaneous thermal analysis, the ability of the treatments to increase the residual amount of biological char in samples during pyrolysis and ability of the flame retardant to be retained in these wood fibres was used to assess the efficiency of each flame retardant on the wood fibres.

WOOD RESEARCH Volume 66, Number 2, 2021
Emília Orémusová and Eva Výbohová

Changes in gross calorific value of thermally treated scots pine (Pinus Sylvestris L.) and sessile oak (Quercus Petraea L.) wood and their explanation using ftir spectroscopy

Scots pine (Pinus sylvestris L.) and Sessile oak (Quercus petraea L.) wood were thermally treated in an oven at the temperatures of 160°C, and 200°C under atmospheric pressure in the presence of air for 3 and 9 hrs. The mass loss and gross calorific value were determined. Non-treated wood samples achieved a gross calorific value of 22 193 J.g-1 for pine wood and 19 277 J.g-1 for oak wood. Whereas the calorific value of pine wood with increasing severity of treatment decreased, in the case of oak it increased. The mass loss increased with increasing treatment severity by both wood species. Mentioned differences in pine and oak wood behaviour using ATR-FTIR spectroscopy were explained. In the case of pine wood with increasing temperature and time of exposure a decrease of resin acids was observed. This may be contributed to decrease in GCV. In the case of oak wood, mainly at temperature of 200°C the degradation of hemicelluloses was observed that results in relative increasing in the lignin content with followed increase in the GCV.