Thermal properties of wood and wood composites made from wood waste

Abstract

Thermal characteristics represented by thermal parameters are very important for wood and wood-based products. They are influenced by internal and external factors such as: structure, temperature, moisture content, etc. Based on these factors the main aim of this article is the presentation of thermal conductivity, thermal diffusivity, and volume specific heat for five selected samples of wood with different moisture contents and wood fibre orientation. The next materials to be assessed were oriented strand boards made from the identical wood types. The wood samples had a tangential and radial orientation of fibres. Thermal conductivity and thermal diffusivity were examined through the use of a dynamic plane source method convenient for materials with the low thermal conductivity. The volume specific heat was calculated from definition equation. The moisture content was measured through the use of the gravimetric method and moisture analyser MAC 210/WH. The experimentally obtained relationships between thermal conductivity, thermal diffusivity and relative moisture content have resulted in increasing progress and in turn, the relationship of volume specific heat to the moisture content can be described by a polynomial function. The final relationships were mathematically described by regression equations and coefficients of determination. In both theoretical and practical contexts, the beneficial results for the thermal parameters of wood composites are made for different types of wood waste made in Slovakia, the thermophysical parameters of which were analysed and compared.