Materials, Methods & Technologies, Volume 8, 2014

Abstract: The existence of life on earth is possible if stored and sustainable develop our surroundings in this and fauna in the forest which occupies the most significant portion. That is why it is vital to use reasonable wood resources and their processing to use environmentally friendly technologies. Thermally wood modification is green technology, like alternative of chemical modification, which damage environment. This technology increase exploitation life of wooden element, because received wood has increase fungus resistance, reduced hygroscopicity and improved dimensional stability [1;2;4;6;7;8;13]. There are four methods for thermally modification of timber: heat treatment in a humid environment; heat treatment in an inert gas; heat treatment in a hot press; heat treatment in oil. Based on these methods have been developed and implemented in four production technologies: Finnish technologies; [Syrjänen 2001]; French technologies [Vernois 2001]; Neiderland technologies (plato process) [Militz and Tjeerdsma: 2001]; German technology [Rapp and Sailer: 2001]. It was found that due to thermal modification of wood of pine radiant in an environment of linseed oil improves dimensional stability and resistance to decay due to the decreased hygroscopicity, but reducing the mechanical performance [Dubey, MK: 2010]. It has been found by other investigators [Rapp, A.O., M. Sailer:2001; Bazyar,B.:2012; Welzbacher, C. R., A.O. Rapp, P. Haller, J. Wehsener:2005]. Properties of thermally modified timber of many species tree are being actively studied in.different countries [ 6;17;18;19;20;21;22 ]. The results of these researches are presented in many papers, whereas the Bulgarian production it is still poorly known (Panayotov,P.A. and Georgiev, Zh.: 2013 ). In this study, timber of three species tree (spruce, beech and poplar) was modified in sunflower oil till temperature 210°C.