THE EFFECT OF THERMAL TREATMENT WITH SATURATED WATER STEAM ON THE PROPERTIES OF BIRCH WOOD

Industrially important properties of wood can be changed due to the modification of birch wood (Betula pendula L.) after the process of thermal treatment with saturated water steam. The birch wood was modified by saturated water steam at 125 +/- 2.5 degrees C for 8 hours and at a pressure of 0.18 MPa. The water contact angle of steam-treated birch wood increased from 42.1 degrees (for untreated birch wood) to 52.4 degrees (for steam-treated birch wood), and the stability of water drop on steam-treated birch wood surface increased. FTIR spectra showed an increase in C=O and glycoside bonds concentration on the surface of steam-treated birch wood, but the concentration of C-O-C groups decreased. XPS measurements confirmed that the concentration of oxygen as well as C=O and C-O-O groups on the surface of steam-treated birch wood showed an increment in comparison with the native wood sample. SEM micro photos confirmed the minor changes of birch wood cells due to the action of saturated water steam modification.