Establishment of patterns in the thermal modification of dry pine wood

Abstract

One of the methods of ensuring the durability of dry wood during operation is its thermal modification, which inhibits the life processes of the fungus of the Ceratostomaceae family and leads to a change in its structure and properties. Therefore, the object of research was thermally modified dry pine wood affected by a fungus of the Ceratostomaceae family. Physicochemical studies of changes in the structure of thermally modified dry pine wood showed that the samples have absorption spectra that are characterized by fluctuations of the glucopyranose ring of cellulose and are an indicator of the beginning of destructive processes. At the same time, the data of thermogravimetric analysis show the processes of water loss and decomposition of hemicellulose, cellulose, and lignin, and burning of coke residue. Bending and compressive strength of thermally modified dry pine wood shows that as the wood dries, the strength limit decreases depending on the degree of fungus damage. Namely, with an area of biological damage within 10 %, the strength limit is reduced by more than 1.2 times when modified at 200 °С/3 hours, by more than 1.9 times at 200 °С/6 hours. With an increase in the degree of fungal damage to 30÷50 %, the strength limit decreases by more than 1.6 times when modified at 200 °С/3 hours, by more than 2.1 at 200 °С/6 hours. And when affected by a fungus in the range of 80÷100 %, the wood becomes softer, more plastic, while the bending strength is reduced by 1.7 times, and the compressive strength by 1.16 times. Thermal modification of dry pine wood at 200 °С for 3 hours reduces the level of water absorption by more than 1.5 times, and for 6 hours ‒ by more than 1.7 times. The practical importance is that the results of determining changes in the structure and properties of thermally modified dry pine wood make it possible to establish the scope and conditions of its application