A study of thermo-hydro-treated (THT) birch wood by chemical analysis and Py-GC/MS

Abstract

The chemical changes in birch wood occurring at thermo-hydro treatment (THT) was studied at temperatures (T) of 150, 160 and 170°C by analytical pyrolysis [Py-gas chromatography/mass spectrometry/flame ionisation detector (GC/MS/FID)], elemental analysis and traditional wet-chemical analysis. THT wood (THTW) was also extracted with acetone. Mass losses (ML) due to THT and acetone extraction of THTW were considered for material balance calculations. The holocellulose and hemicellulose (HC) contents decrease with increasing THT temperature (THTT), thus the apparent lignin content is elevated by ca. 20%. The HC degradation begins at 150°C, while that of α-cellulose modification at 170°C. Compared to unmodified birch, the THT170°Cmaterial contains ca. 10% less α-cellulose and up to 40% less HC. The Py-GC/MS also indicates decreasing amounts of volatile products from polymeric carbohydrates (CHs) and lignin origin as a function of increasing THTT. The identified CH-based Py products of THT170°Cof non-extracted (ne) and extracted (e) materials resulted in 13 and 22% weight decrements, respectively, while the lignin-type Py products were reduced by 13 and 49%, respectively. With increasing THTT, the total content of CO2, water and methanol decreases, and the amount of unidentified compounds increases by 30%.

Extract of Albizia kalkora leaves

“…Next, we will increase the temperature to 120 °C at the rate of 5 °C/min. Finally, we increased the temperature to 200 °C at a rate of 10 °C/min for 2 minutes [14][15][16].…”

Influence of hydrothermal treatment on hemicellulose structure in Cryptomeria japonica

“…Previously, researchers used quantification and composition analysis to investigate the effect of thermal treatment on hemicellulose chemical structure (Altgen et al 2018;Wang et al 2019). Based on pyrolysis-gas chromatography-mass spectrometry analysis of wood materials, the production of oligomers or monosaccharides derived from hemicellulose in cell walls were mainly detected under HTT conditions (Romagnoli et al 2018;Andersone et al 2019). However, the investigations in hemicellulose caused by HTT have been limited to the quantification and composition analysis of oligomers or monosaccharides (Garrote et al 1999;Altgen et al 2018).…”

Conditions Influencing Mould Growth for Effective Prevention of Wood Deterioration Indoors

“…On the other hand, the mould resistance of heat-treated wood is only slightly improved, despite the significantly reduced amount of hemicelluloses [20,21]. However, this could be attributed to the mould growth enhancing factors such as the removal of all initial antifungal extractives and the increase in the amount of monosaccharides [20,22]. In general, none of these previously mentioned factors concerning nutrients could eliminate mould growth as the nutritional requirements are usually minimal and satisfied either by the material constituents or by a minor contamination of the surface by dust or other deposit [13].…”