Derya Sevim Korkut

The Effects of Heat Treatment on the Physical Properties and Surface Roughness of Turkish Hazel (Corylus colurna L.) Wood

Heat treatment is often used to improve the dimensional stability of wood. In this study, the effects of heat treatment on the physical properties and surface roughness of Turkish Hazel (Corylus colurna L.) wood were examined. Samples obtained from Kastamonu Forest Enterprises, Turkey, were subjected to heat treatment at varying temperatures and for different durations. The physical properties of heat-treated and control samples were tested, and oven-dry density, air-dry density, and swelling properties were determined. A stylus method was employed to evaluate the surface characteristics of the samples. Roughness measurements, using the stylus method, were made in the direction perpendicular to the fiber. Four main roughness parameters, mean arithmetic deviation of profile (Ra), mean peak-to-valley height (Rz), root mean square roughness (Rq), and maximum roughness (Ry) obtained from the surface of wood were used to evaluate the effect of heat treatment on the surface characteristics of the specimens. Significant difference was determined (p = 0.05) between physical properties and surface roughness parameters (Ra,Rz, Ry, Rq) for three temperatures and three durations of heat treatment. The results showed that the values of density, swelling and surface roughness decreased with increasing temperature treatment and treatment times. Turkish Hazel wood could be utilized successfully by applying proper heat treatment techniques without any losses in investigated parameters. This is vital in areas, such as window frames, where working stability and surface smoothness are important factors.

Experimental Test of Heat Treatment Effect on Physical Properties of Red Oak (Quercus falcate Michx.) and Southern Pine (Pinus taeda L.)

The objective of this work was to evaluate the effect of heat treatment and compression on the swelling and surface roughness of Southern red oak (Quercus falcate Michx.) and Southern pine (Pinus taeda L.). Specimens were exposed to temperature levels of 110 °C or 200 °C for 8 h before they were compressed using 2.5 MPa pressure for 5 min. Swelling values of the control and heat-treated samples in three grain orientations were evaluated by soaking them in water for 48 h. A stylus method was employed to determine the surface characteristics of the samples. Three main roughness parameters, namely mean arithmetic deviation of profile (Ra), mean peak-to-valley height (Rz), and maximum roughness (Rmax) were used to evaluate the effect of heat treatment on surface characteristics of the samples. Oak and pine specimens had 39.8% and 28.7% lower tangential swelling values, respectively, than those of control samples as a result of exposure to a temperature of 200 °C. Heat treatment did not make any significant difference on surface quality. Micrographs taken from cross sections of the specimens revealed that there was some cell distortion and modification due to heat treatment as well as compression. Combination of heat treatment and compression can be considered an alternative method to improve certain physical properties of these two species.

Impact of impregnation with Imersol Aqua on the surface adhesion strength of synthetic, acrylic, polyurethane, and water‐based varnishes

Purpose – The purpose of this paper is to determine the effect of Imersol Aqua impregnation of Scotch pine, Oriental spruce, and Uludag fir on the surface adhesion strength of various types of varnishes. The finding obtained would benefit the manufacturers of building materials and furniture, where the surface adhesion strength of water‐based varnishes is a concern.Design/methodology/approach – For this purpose, test samples were prepared from Scotch pine, Oriental spruce, and Uludag fir woods that met the requirements of ASTM D 358. The samples were impregnated with Imersol Aqua using short‐, medium‐, and long‐term immersion techniques according to ASTM D 1413 and the manufacturers instructions. After impregnation, surfaces were coated with synthetic, acrylic, polyurethane, and water‐based varnishes in accordance with ASTM D 3023 standards. After the varnishing process, the adhesion strength of the samples was determined in accordance with ASTM D 4541.Findings – It was also found that among the wood sam...

How impregnation with boron compounds affects the surface hardness of some varnishes

Purpose – The purpose of this paper is to investigate how impregnation with boron compounds affects the surface hardness of varnished wood materials.Design/methodology/approach – Test samples were prepared from Scotch pine, Oriental spruce, and Uludag fir, which met the requirements of ASTM D 358.These samples were impregnated with boric acid (Ba) and borax (Bx) using a vacuum technique, according to ASTM D 1413 guidelines. After impregnation, surfaces were coated with cellulosic, synthetic, polyurethane, water‐based, acrylic, and acid‐hardening varnishes in accordance with ASTM D 3023 guidelines. Surface hardnesses of specimens after the varnishing process were determined, in accordance with ASTM D 4366 guidelines.Findings – Surface hardness was greatest for samples of spruce treated with Ba and polyurethane varnish, and lowest for samples of Scotch pine treated with Bx and synthetic varnish. With regard to wood type, impregnation material, and varnish type, surface hardness was greatest for Oriental spr...