Browsing by Author "Akyildiz M."

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Bonding strengths of poly(vinyl acetate), Desmodur-VTKA, phenol-formaldehyde and urea-formaldehyde adhesives in wood materials impregnated with Vacsol Azure
(2009-10-01) Keskin H.; Atar M.; Akyildiz M.
This study has been performed to determine the impacts of Vacsol Azure (VA) on the bonding strength of poly(vinyl acetate) (PVAc), Desmodur-VTKA (D-VTKA), urea-formaldehyde (UF) and phenol-formaldehyde (PF) adhesives on some impregnated wood materials. To this end, the test samples prepared from Oriental beech (Fagus orientalis Lipsky), European oak (Quercus petraea Liebl.), Scotch pine (Pinus sylvestris Lipsky), European linden (Tilia cordata) and Lombardy poplar (Populus nigra Lipsky) woods materials were treated with Vacsol Azure by the Vac-Vac double vacuum impregnation process of ASTM D 1413 standards and directions of the manufacturer. After impregnation, bonding strength test (based on BS EN 205) was applied on both sanded connection surfaces jointed by PVAc, D-VTKA, UF and PF adhesives. Consequently, in the interaction of the impregnated wood materials and adhesive types, the highest bonding strength was obtained in Oriental beech + PVAc (9.707 N mm-2) and the lowest was obtained in Lombardy poplar + UF (3.758 N mm-2). In consequence, in the massive constructions and furniture elements that the bonding strength after the impregnation with Vacsol Azure is of great concern, bonding with PVAc of Oriental beech wood materials could be recommended. © 2009 Elsevier Ltd. All rights reserved.
Effect of the heat treatment on the adhesion strength of water based wood varnishes
(2015-01-01) Kesik H.; Akyildiz M.
Effects of heat treatment on the adhesion strength of water based wood varnish were studied using four tree species woods [Anatolian black pine (Pinus nigra J.F. Arnold subsp. nigra var. caramenica (Loudon) Rehder), Calabrian pine (Pinus brutia Ten.), Sessile oak (Quercus petraea Liebl.) and Sweet chestnut (Castanea sativa Mill.)] and two components water based varnish (one-component semi-matte and two-component glossy water-based varnish). Those tree species' woods were selected randomly from timber merchants as test materials because of their wide use in industry. Under atmospheric pressure, the wood samples were subjected to three different temperatures (130, 180 and 230°C) at two different time intervals (2 and 8 h). After that, the wood samples were coated with two components water-based varnish. Adhesion strength of varnish film was then measured with a pull-off test according to the ASTM-D 4541 (1995). The coatings presented the highest adhesion strength (3.33 MPa) on oak wood, followed of the adhesion strength on chestnut (2.1 MPa) and on pine species (black pine 1.78 and Calabrian pine 1.65 MPa) Sessile oak wood showed the highest adhesion strength (3.33) followed by Sweet chestnut (2.19) and pine species (Anatolian black pine 1.78 and Calabrian pine 1.65 MPa). The adhesion strength of all wood types decreased increasing temperature and time.