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Öğe Determination of bonding performance of several modified wood adhesives(2011) Altınok, Mustafa; Atar, Musa; Keskin, Hakan; Korkut, Süleyman; Kocatürk, İlhanWe have assessed the effect on bonding performance of modifying synthetic wood adhesives. Wood samples were prepared from Scots pine (Pinus sylvestris L.) and oriental beech (Fagus orientalis L.). Samples were bonded using poly(vinyl acetate) (PVAc) and urea-formaldehyde (UF) adhesives modified with melamine-formaldehyde (MF) and phenol-formaldehyde (PF). Modified formulations included PVAc alone, PVAc + UF (at 15, 35 and 50% UF), UF alone, UF + MF (at 15, 35 and 50%), and UF + PF (at 15, 35 and 50% PF). Samples were exposed to three experimental environments: Standard atmosphere, cold water, and boiling water. For bonding strength determination, we used DIN 53 255 standard. We conclude that the adhesive modifications tested generally have no significant effect on bonding performance under standard atmospheric conditions, but do increase bonding performance under cold and boiling-water conditions. The best adhesive bonding strength was found using oriental beech samples with the UF + MF (50%) adhesive: 9.24 N/mm2 bonding strength under standard atmosphere conditions, 6.06 N/mm2 in cold water, and 4.39 N/mm2 in boiling water. © 2011 Academic Journals.Öğe How impregnation with boron compounds affects the surface hardness of some varnishes(Emerald Group Publishing Limited, 2011) Atar, Musa; Keskin, Hakan; Korkut, Süleyman; Korkut, Derya SevimPurpose - 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 spruce impregnated with Ba and polyurethane varnish and lowest for Scotch pine impregnated with Ba and synthetic varnish. Thus, impregnation with boron compounds increased the surface hardness of the varnished wood. Research limitations/implications - A protective coating (such as varnish) has limited resistance to external effects and the lifetime of the coating will be determined by the type and severity of conditions to which it is exposed. Practical implications - Types of varnishes, wood materials, and impregnation chemicals affect surface hardness and can influence the usefulness of wood materials, where surface hardness values are important. Originality/value - The study results reported in the paper help address the lack of research in this field and should be informative, in particular, for manufacturers and consumers in the furniture and decoration sector.Öğe Impact of impregnation with boron compounds on combustion properties of oriental beech (Fagus orientalis Lipsky) and varnishes(Academic Journals, 2011) Atar, Musa; Keskin, Hakan; Korkut, Süleyman; Korkut, Derya SevimThis study examined the impacts of varnishing after impregnation with boron compounds on combustion properties of oriental beech. The test samples prepared from oriental beech (Fagus orientalis Lipsky) wood were impregnated according to ASTM D 1413-76-99 with boric acid (Ba) or borax (Bx) using a vacuum technique. After impregnation, one of six varnishes (cellulosic (Cv), synthetic (Sn), polyurethane (Pu), water-based (Wb), acrylic (Ac) or acid-hardening (Ah) was applied in accordance with ASTM D 3023 coated surfaces. After treating, varnishing and conditioning, the combustion properties of samples were determined according to ASTM E 160-50. Combustion temperatures for Bx and Wb were highest when testing without flame source combustion (WFSC), while Ba and Pu exhibited the lowest temperature when testing for flame source combustion (FSC). For the combination of combustion type, impregnation material and varnish type, combustion temperature was the highest for WFSC + boric acid + water-based varnish, but the lowest for WFSC + boric acid + synthetic varnish. As a result, the tested varnishes showed an increasing impact, but boron compounds (Ba and Bx) showed a decreasing impact on the combustion properties of beech. In conclusion, for usage areas having a high risk of fire, impregnation of wood material with boron compounds before varnishing will decrease combustion temperature and provide some degree of security.Öğe Impact of impregnation with Imersol Aqua on the surface adhesion strength of synthetic, acrylic, polyurethane, and water-based varnishes(Emerald Group Publishing Limited, 2011) Keskin, Hakan; Atar, Musa; Korkut, Süleyman; Korkut, Derya SevimPurpose - 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 manufacturer's 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 samples, the adhesion strength was highest in Scotch pine and lowest in Uludag fir. The synthetic varnish produced the highest adhesion strength, whereas polyurethane and acrylic varnishes had the lowest adhesion strength. The adhesion strength was highest after medium-term immersion and lowest after long-term dipping. The highest adhesion strength (4.299 MPa) was produced by a combination of Scotch pine, medium-duration immersion, and the use of a wood-based varnish. The lowest adhesion strength (2.090 MPa) resulted from the combination of Uludag fir, long-term immersion, and a water-based varnish. Research limitations/implications - Impregnating woods using materials with appropriate water repellent, biotic, and abiotic effects before the application of varnishes and paints is important for long-term protection against photochemical degradation, dimensional changes, biological factors, and fire. Practical implications - The effect of a varnish on surface adhesion strength can determine the usefulness of the varnish. Originality/value - Improving surface adhesion of some varnishes via medium-term impregnation with Imersol Aqua impregnation should be used on Scotch pine, Oriental spruce, and Uludag fir woods which could be used in the manufacturing of building materials and furniture, where the surface adhesion strength of water-based varnishes is a concern.Öğe Laminated veneer lumber from Rowan (Sorbus aucuparia Lipsky)(Academic Journals, 2009) Kol, Hamiyet Şahin; Keskin, Hakan; Korkut, Süleyman; Akbulut, TurgayThis study was designed to determine some physical and mechanical properties and surface roughness of laminated veneer lumber (LVL) made from Sorbus aucuparia Lipsky wood which has no detailed research in the literature. The sample trees were taken from the Kure district in Kastamonu, Turkey. The 12 ply LVLs manufactured from 1.6 mm thick rotary peeled veneers and bonded with urea formaldehyde adhesive. Conventional methods followed and the test procedures were performed on small clean specimens. Also, this study involves the comparison of the mechanical properties of LVL made from S. aucuparia Lipsky wood to those of conventional LVLs. It was found that air-dry density, thickness swelling, thermal conductivity, MOR and MOE, compression strength, surface hardness, shear strength and surface roughness (Ra) were 0.737 g/cm(3), 3.63%, 0.2259 W/m-K, 80.6 N/mm(2), 6985.6 N/mm(2), 58.36 N/mm(2), 29.15 N/mm(2), 5.28 N/mm(2) and 5.13 mu m respectively. When S. aucuparia L. wood is used to produce LVL for use in the furniture industry, the resulting physical and mechanical property values are sufficient to produce an acceptable product. Also, it appears to be a suitable alternative to currently used alnus spp. and fagus spp. according to usage area.Öğe Scratch resistance of cellulosic, synthetic, polyurethane, waterborne, and acid-hardening varnishes used on woods(Elsevier Science Bv, 2010) Keskin, Hakan; Atar, Musa; Korkut, Süleyman; Tekin, AhmetThis study was conducted to determine the scratch resistance of cellulosic (C), synthetic (Sn). polyurethane (Pu), waterborne (Wb), and acid-hardening (Ah) varnishes used on wood materials. Test samples were prepared from Scotch pine, oriental beech, European oak, black poplar, basswood, and black walnut woods that met ASTM D 358 requirements and were coated according to ASTM D 3023 standards with C, Sn, Pu, Wb, and Ah varnishes. The scratch resistance of the samples after the varnishing process was determined based on TS 4757. The greatest scratch resistance was obtained for walnut based on the wood species, whereas the least scratch resistance was obtained for poplar. As for varnish type, the greatest scratch resistance was obtained for synthetic varnish, whereas cellulosoic varnish had the least scratch resistance. In addition, the greatest scratch resistance was obtained for three layers based on the layer thickness, whereas the least scratch resistance was calculated for one layer. Based on the wood species, varnish type, and layer type, the greatest scratch resistance was found for oak + Pu + three layers, and the least scratch resistance was calculated for basswood +Wb + one layer. Furthermore, differences were observed according to varnish type and layer thickness: varnish types were efficient for scratch resistance to the first degree and layer thickness to the second degree. The results showed that a varnish application with three layers of polyurethane provides a durability advantage. (C) 2009 Elsevier B.V. All rights reserved.
