Research of the process of water absorption by thermally modified wood

Abstract

The analysis of the process of thermal modification of wood, which was obtained by a controlled process of pyrolysis of wood heating (> 180 °C), which causes some chemical changes in the structures of cell wall components (lignin, cellulose and hemicellulose), to increase its durability. It is proved that in the process of thermal modification there is a decomposition of hemicelluloses and amorphous part of cellulose, reduction of water absorption, and also the quantity of substances which are the environment for development of fungi decreases. In addition lignin and psevdolihnin formed by the process of polymerization and redistribution in cell volume and cell walls provide higher density, hardness, increase the hydrophobicity (water repelling), thereby reducing their ability to absorb moisture and swell. Polymerised lignin fills the inside of the cell – formed closed porous structure with low ability to bind water. It was established that the most effective option to reduce such substances are temperature and exposure time. The results of water absorption, dependence on which the calculated diffusion coefficient in the water absorption. Thermal modification of wood reduces water absorption by more than 10 times within 6 hours, which allows it to be used on objects with high humidity.