Usability of wood tar from heat treatment process as a wood preservative

In this thesis, it was aimed to determine the efficiency of wood tar released during heat treatment process as a wood preservative. Samples of scots pine sapwood (Pinus sylvestris L.) were impregnated with wood tar (10 and 20% of tar) by using full cell and empty cell methods. Epoxidized linseed oil (ELO) was prepared and impregnated the samples previously treated with wood tar in order to prevent leaching of wood tar. Water absorption and dimensional stability (AWPA E4), toxicity test , decay test (EN 113), insect test (EN 46), compression strength (DIN 185), modulus of elasticity and modulus of rupture (DIN 186) and thermogravimetric analysis were used in order to determine the efficiency of treated wood samples. According to water absorption and anti-swelling efficiency, the lowest water absorption and tangential/radial swelling rate were obtained from the samples impregnated with wood tar + ELO and only ELO. Malt-agar media prepared from leachate was toxic for Coniophera puteana. Treated samples were leached for 2 weeks before decay test. Leached samples were exposed to white (Trametes versicolor) and brown (Coniophora puteana) rot fungi according to the EN 113 standard. Weight losses of treated samples were found less than 5%. According to EN 46; the least amount of surviving larvae obtained from the samples impregnated with 20% of wood tar. Regarding mechanical properties, wood tar decreased the mechanical strength of the samples. According to thermogravimetric analysis results, the most resistant group to thermal degradation was determined the samples impregnated with 10% wood tar.