Effect of thermo-vacuum modification on selected chemical, physical, and mechanical properties of Siberian larch (Larix sibirica L.) wood

ABSTRACT

The primary aim of this research was to investigate and evaluate the effects of thermo-vacuum modification through forced convection on selected chemical, physical, and mechanical characteristics of Siberian larch (Larix sibirica L.) wood. Larch wood boards were thermally-modified, using press-vacuum plant technology, for three hours at a temperature of 200 °C and a pressure of 350 mBar. In order to characterise the thermally-modified (TH) and unmodified (CTRL) wood samples, the extractives, lignin and holocellulose content, volumetric swellings, compression strength, and modulus of elasticity (MOE) were determined. Gas chromatographic-mass spectrometric (GC-MS) analysis revealed chemical compound changes as a result of the thermal modification process where some extractives became undetectable after treatment while some new extractives were detected. Thermally-modified larch wood exhibited lower volumetric swelling compared to the untreated samples. Markedly, thermally-modified larch wood had lower tendency to absorb moisture. In addition, thermally-treated wood had slightly higher compression strength parallel to the grain, which was 0.29% higher than that of unmodified samples. Meanwhile, a 7.6% reduction in MOE was recorded in the thermally-treated wood.

KEYWORDS:

• Thermal treatment
• dimensional stability
• mechanical strength
• volatile organic compounds

Acknowledgment

This manuscript reflects only the authors’ views and opinions, neither the European Union nor the European Commission can be considered responsible for them.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This study was carried out within the Agritech National Research Center and received funding from the European Union Next-GenerationEU (PIANO NAZIONALE DI RIPRESA E RESILIENZA (PNRR) – MISSIONE 4 COMPONENTE 2, INVESTIMENTO 1.4 – D.D. 1032 17/06/2022, CN00000022). This research was also supported by the Slovak Research and Development Agency under contract No.SK-CZ-RD-21-0100. This manuscript reflects only the authors’ views and opinions, neither the European Union nor the European Commission can be considered responsible for them.