Abstract
The effect of thermo-hydro treatment (THT) on the properties of birch (Betula spp.) wood veneers has been studied. THT was carried out in a multi-functional pilot scale wood modification device of wood treatment technology (WTT, Latvia) under elevated water vapor pressure conditions at four combinations of temperature and treatment time (°C/min): 150/10; 150/50; 160/10 and 160/50. After THT, the following veneer properties were examined: mass loss (ML), chemical composition, bending strength (BS), tensile strength (TS), equilibrium moisture content (EMC), resistance to decay by mould and blue stain fungi, and surface contact angle (CA). The chemical components were changed by THT. Increased THT temperature and time resulted in hydrophobization of veneers as indicated by decreasing EMC and increasing CA data. All THT were effective against wood discoloring fungi, although insufficient decay resistance was observed. The mechanical strength properties of THT veneers were also deteriorated.
Acknowledgments
The authors gratefully acknowledge the financial support by the European Regional Development Fund project “Plywood from thermally modified veneer with improved durability properties” No. 2014/0018/ 2DP/2.1.1.1.0/14/APIA/VIAA/040. We would also like to express special thanks to Kristine Meile for analysis of water extractives and Andis Antons for help in mechanical tests.
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