Effect of Heat Treatment on Wettability and Modulus of Elasticity of Pine and Spruce Wood

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. Specimens were cut out of planed beams. Then 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 degrees 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 sessile drop technique. 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. Modulus of Elasticity (MOE) of pine wood decreased, while MOE of spruce slightly increased after heat treatment.