Unevenly distributed thermal treatment of wood: preliminary study—density profiles

Abstract

The present study aims to produce material with unevenly distributed density over cross section using thermal treatment. Beech (Fagus sylvatica L.) wood in dimensions of 65 × 65 × 700 mm³ (R × T × L) was studied. Thermal modification at 160, 200 and 230 °C was applied for different time exposure and evaluated using mass loss. Then, density profiles were measured in order to analyze density distribution over cross section. Low temperature and short process duration (15, 30, 60 and 120 min) with mass loss between 0.15 and 1.1 % were considered to be insufficient, whereas higher temperature of 200 and 230 °C with average mass loss of 3.9 and 10 %, respectively, provides evenly modified cross section. However, uneven density profile was found for treatments at 230 °C and ten 15 min intervals of exposure. Material with thermally modified surfaces with improved properties but unchanged mechanical behaviour in the middle section would provide another solution for applications for building purposes.