Effect of heat treatment on wettability and MOE of pine and spruce wood

Abstract

This research was performed in order to determine how the heating process affects the wettability and mechanical properties of spruce (Picea abies) and pine (Pinus silvestris) wood. Studies were carried out using wood heated in laboratory. The measurements of specimens were 315x20x20mm. Specimens were divided into the following four groups: specimens of one group were not exposed to heating, whereas specimens of three other groups were subjected to heating at the temperature of 190○C for 1 to 3 hours respectively, in the air under atmospheric pressure. Both heated and unheated specimens were moistened and dried in a climatic chamber. Before and after treatment the mechanical properties of specimens were assessed using the original method of transverse vibrations and contact angle measurements were carried out using the water drop method. The results showed a significant increase in wood hydrophobicity after treatment. Spruce contact angle after treatment increased from 1.3 to 1.45, pine from 1.4 to 2 times. MOE of pine wood decreased, while MOE of spruce slighty increased after heat treatment. Wood equilibrium moisture content after treatment is redused and it is known, that the drier the wood - the better its mechanical properties. This factor may have the biggest influence to such result.DOI: http://dx.doi.org/10.5755/j01.ms.21.3.7304

Keywords

• heat-treated wood, pine, spruce, sorption, mechanical properties, nondestructive evaluation, wettability