THE EFFECT OF TEMPERATURE HEAT TREATMENT OF WOOD FILLER ON BIODEGRADATION OF THE COMPOSITE BASED ON POLYVINYL ALCOHOL

Rising of environmental problems has led to awareness of the need to find the alternative to synthetic composite material. Such widely used materials at present are the natural composites, which are environmentally friendly and biodegradable, i.e. are degradable in a natural environment. The article describes the results of investigation of the composite polymer able to decomposition in the natural environment polyvinyl alcohol and wood filler. Composites containing PVA and wood flour under natural conditions are responded to relatively rapid biodegradation due to the fact that hygroscopic wood flour has high sorption abilities. In this regard the preliminary thermo modification of wood filler, which allows significantly reducing of water absorption and swelling of wood is proposed. In this study the influence of thermal pre-treatment of wood filler on the sorption and strength properties of composites is analyzed. It is revealed that under the natural conditions the filled composites that were subjected to heat treatment at temperatures of 220 - 240 degrees C have sorption characteristics 1.8 times lower than the composites with unmodified wood flour, which contributes to a longer biodegradation of the material. However, the composites with thermally modified filler are characterized by a decrease of the strength properties at 20 % below. Thus, adjusting the temperature of modification of the wood filler, you can set the time of biodegradation of the composites in the natural environment, which gives the possibility of manufacturing products with a pre-desired decomposition. For example a composite material with a longer biodegradation can fmd its application in packaging, with less long - in agriculture.