Investigation of some physical and mechanical propertiesof heat-treated wood materials with different methods

In this thesis, some physical and mechanical properties of wood materials heat-treated by different methods and under different temperature conditions were investigated. Samples prepared from Scotch pine (Pinus Silvestris L.) and European beech (Fagus Sylvatica L.) woods were heat treated separately at 170 °C, 190 °C and 210 °C using hot air, oil treatment and ThermoWood methods. Air dry density (TS ISO 13061-2), water absorption rate and dimensional change (TS ISO 13061-15) tests were performed to determine the physical properties and static bending strength (TS ISO 13061-3), modulus of elasticity in bending (TS ISO 13061-4) and Janka hardness (TS ISO 13061-12) tests were performed to determine the mechanical properties of the heat treated and control group samples. According to the results of the study, the applied heat treatment methods and temperature levels affected the physical and mechanical properties of the wood samples differently. For all methods, the water absorption and dimensional change values of the wood samples decreased after heat treatment and also with increasing temperature. In particular, the hygroscopicity of the samples subjected to oil heat treatment was greatly reduced and the dimensional stability was significantly increased. In addition, the density values increased in the oil heat treatment method in contrast to the other two methods. On the other hand, the density, hardness and mechanical strength properties of Scotch pine and European beech samples decreased with temperature increase in all heat treatment methods. However, in ThermoWood and especially in oily heat treatment methods, the mechanical strength and hardness values increased after heat treatment at low temperature (170 °C) compared to the samples without heat treatment. Compared to the hot air method, generally higher strength and hardness values were determined in the ThermoWood method. However, the most successful results for both wood species were found in the oil heat treatment method. Keywords: Wood materials, Heat treatment temperature, Heat treatment method, Physical and Mechanical properties.