The infuence of chemical treatments on dimensional stability of Narrow leaved Ash

Abstract

Chemical treatments may cause various changes in wood chemical composition, such as the removal of extractives and certain parts of lignin, hemicelluloses and cellulose. This may involve variety of chemical reactions in wood material. The effects of the applied treatments depends on the treatment conditions (type and concentration of chemicals, pH value, temperature, pressure, treatment duration), but also on the characteristics of lignocellulose material itself. Treatments may change the hydrophilic character of wood, which may affect its dimensional stability. This paper presents the study on the influence of the acetic acid and sodium carbonate treatments on the dimensional stability of Narrow-leaved Ash. All the treatments with acetic acid solutions have improved the dimensional stability of the samples. It was also improved after the treatments with the lowest concentration of sodium carbonate solution (AT 1). However, increased concentration of sodium carbonate and the higher temperature applied had negative effects on dimensional stability of the samples.