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Öğe Eco-friendly particleboards with low formaldehyde emission and enhanced mechanical properties produced with foamed urea-formaldehyde resins(Elsevier Science Ltd, 2022) Kelleci, Orhan; Köksal, Süheyla Esin; Aydemir, Deniz; Sancar, SemihUrea formaldehyde (UF) is the most widely used thermoset glue in the wood composite board industry. UF has formaldehyde emission, which is harmful to the environment and human health. In this study, it was aimed to ensure more efficient use of glue by foaming UF, as well as to reduce the amount of formaldehyde emission and thus to realize a cleaner production. In the UF resin foaming process, egg white (EW) and blood flour (BF) were used as foaming agents, which increased the resin volume by 4-7 times. Ammonium sulfate (AS) was used as a hardener for the UF. The UF resin and AS solid concentrations were 65% and 30%, respectively. The resins used in the production were prepared by blending UF, AS, and blowing agents using a mixer at 1000 rpm. The resin was then sprayed onto the surface of the wood chips via an air gun under 5 bar pressure. The PBs were produced as a monolayer from only a core layer (CL) of wood chips. The obtained PBs were characterized by their physical and mechanical properties and formaldehyde emissions. The morphological characterization of the foamed resins was also examined. The results showed that the foaming process had improved the mechanical properties of the PBs by about 30%; however, no significant differences were found in the physical properties of the PBs. Morphological characterization showed that the UF foaming with blow agents had proved to be successful and the resin volume had been increased 4-7 times by the foaming. Formaldehyde emissions were found to be lower (2.5-5.1 mg/100 g) than for the un-foamed resins (3.95-7.31 mg/100 g). It was concluded that PBs with good mechanical properties and low formaldehyde emission can be manufactured by using 30% less UF resin.Öğe The Effect of Different Ambient Temperatures on the Adhesion Performance of Black Pine (Pinus nigra) Wood(2024) Kelleci, Orhan; Köksal, Süheyla EsinIn this study, the adhesion performance of wood glues was evaluated depending on temperature. Polyvinyl acetate (PVA) and poly urethane (PU) glue were used to adhere to the Back pine (Pinus nigra) wood samples. The adhesion performance of the samples was determined under three different temperature effects: below room temperature (4 ° C), at room temperature (22 ° C), and above room temperature (55 ° C). After sticking, the samples were clamped with a hand vise and left to cure at three different temperatures. Lap sheer strength (LSS), modulus of rupture (MOR) and modulus of elasticity (MOE) analyses were performed for the mechanical characterization of the samples. According to the obtained results, the LSS (Load at Specified Strain) strength increased below and above room temperature. In contrast, the MOR (Modulus of Rupture) and MOE (Modulus of Elasticity) strengths decreased below and above room temperature. Thus, it was concluded that in addition to the adhesive strength varying with temperature, the direction of the force application also influences the strength. Especially in small workshops, the ambient temperature is greatly influenced by summer and winter conditions. This, in turn, affects the adhesive strength and the quality of the work for wood bonding. Supporting small and medium-sized enterprises (SMEs) with similar studies is essential to improve the quality of their work.Öğe Evaluation of urea formaldehyde (UF) as a surface coating material: Black pine wood and oriented strand board (OSB) coating by enhanced UF(2023) Kelleci, Orhan; Köksal, Süheyla EsinIn this study, the applicability of a urea formaldehyde (UF) resin as a wood surface coater was investigated. Organic fillers were used in the resin solution to prevent crack formation on the surface covered with UF resin. Oriented strand board (OSB) and Black pine (Pinus nigra Arnold.) massive wood were used to prepare the samples. To prepare the control group, 4 g of ammonium sulfate (AS) was added to 100 g of UF and blended at 1000 rpm for 5 min. The first group was prepared using 5 g of wheat flour (WF) in 100 g UF as an organic filler. The second group was prepared by adding 5 g of cellulose fiber (CF) to a 100 g of glue solution, and the results were compared with those of the control group. The mechanical characterization of the samples (abrasion and scratch analysis) and staining analyses of the samples were determined according to the relevant standards. In addition, the samples were subjected to accelerated weathering by manually applying periodic moisturizing and drying. According to the results, the abrasion and scratch resistances of the black pine samples were higher than those of the OSB samples. Although the addition of WF reduced the abrasion and scratch resistance of the surfaces, it also eliminated the crack formation on the surface before weathering. The abrasion and scratch analysis results of boards coated with UF were much higher than those of the particleboards and fiberboards covered with decorative paper. The weathering process increased stain visibility in all samples, especially in the WF-added sample. After weathering, an approximately 30-40% decrease in scratch and wear resistance was observed in all the samples. As a result, it was concluded that UF can be used to coat the surfaces of wooden boards together with organic fillers in semi-outdoor environments.Öğe Installation of test setup and measurement procedures in fir wood hydraulic conductance measurement(Zagreb Univ, Fac Forestry, 2021) Köksal, Süheyla Esin; Gündüz, Gökhan; Kalkat, MenderesFor a hydraulic conductor, through which liquid flows, hydraulic conductance (K, ml.s(-1).MPa-1) is defined as the ratio of pressure difference at the inlet and outlet to the fluid amount passing through the hydraulic conductor in a unit time period. This property is one of the key functions of the wood, and is obtained by the flow rate (F - Flow, ml.s(-1)) along the wood sample divided by the pressure difference driving the flow (Delta P MPa). This study aimed to establish a test setup to determine the hydraulic conductance values of Uludag Fir (Abies bornmulleriana Hattf). A test setup was established to measure the amount of water that flows in samples and pressure difference in characterized capillary tubes. In addition, calibration of the test apparatus is explained in detail. Fir wood samples taken from Yedigoller, which is affiliated to Kale Operation Chieftainship and Bolu Forest Regional Directorate, of 4 mm in diameter and 3 cm in length were prepared and hydraulic conductance measurements were performed, and the results are presented in this article. The installed test setup was used to obtain the following information about frees: operation of the hydraulic conduction system, the amount of needed water, seasonal effects and stress-related changes.Öğe Nickel plating on wood and wood composite surfaces: Characterization of surface durability(2023) Kelleci, Orhan; Köksal, Süheyla Esin; Ulutepe, ErolIn this study, the performance of nickel plating on wooden surfaces was investigated. Black pine (BP), medium density fiber board (MDF) and particle board (PB) were used for the wooden samples. After the sample surfaces were sanded with 200, 500 and 1000 grit sandpaper and varnished with polyurethane varnish (150 g/m2), they were nickel plated using a spray gun and compressed air. After drying the samples at room temperature for 72 h, scratch analyses were performed according to TS EN 15186 (2012) and TS EN ISO 2409 (2020) and abrasion analyses were performed according to TS EN 13329 +A. The staining resistance of the samples was determined according to the DIN 53799 standard. According to the results, surface strength of the MDF samples was lower than those of PB and BP. The scratch analysis results for the black nickel coating were lower than those for TS EN 15186 (2012). However, it was higher according to TS EN ISO 2409 (2020) scratch analysis. In terms of stain resistance, all samples were found to be resistant to water, soap, tea, and acetone stains, except for coffee stains. Upon visual examination, a slight coffee stain was observed on the sample surfaces. As a result, in the light of surface strength analysis, it was concluded that the surfaces of wooden boards are not suitable for nickel plating.Öğe Production and Characterization of Particle Board Laminated with Wall-paper and Wood Veneer(2023) Kelleci, Orhan; Köksal, Süheyla Esin; Tekingündüz, GülIn this study, the lamination process on the particle board (PB) surface was carried out during the board production and the possibilities of saving wood raw material, time, labor and cost by producing the board without the need for cooling, sanding and a separate lamination process were investigated. For this purpose, ready-to-use boards were obtained by covering the board surfaces with wallpaper (WP) and beech veneer (BV) with a single hot press process. The boards were obtained by placing wallpaper and beech veneer on the surface of the chipboard draft prepared in a single layer with a thickness of 16 mm and pressing. No fine wood chips were used on the surface. 1mm thickness BV and 300 gr/m2 WP were used to cover the PB surfaces. Urea formaldehyde (UF) was treated the surface of 2 % humid wood chips (CL) according to its dry weight by 10 % and ammonium sulfate (AS) with 4 % according to solid UF. Concentration of UF and AS were 65 % and 30 % before the treated the wood chips. Particle boards were produced at 650 kg/m3, at 190°C for 10 minute, by applying 30 kg/cm2 pressure on PB. Density, water absorption (WA), thickness swelling (TS), modulus of rupture and elasticity (MOR and MOE), internal bond (IB), density profile and formaldehyde emission were determined according to the relevant TSE standards. According to the obtained results, IB strength of the coated PBs were lower than the control PB. But MOR and MOE strength were high then control samples due to BV and WP. Formaldehyde emissions of covered PBs were less than control samples. As a result, it was concluded that it is possible to produce the PB by pressing at the same time with coating materials. However, it is not currently suitable for furniture production due to its low IB strength, but it can be used as construction building material such as prefabricated house wall.Öğe Yonga Levha (Sunta) ve MDF Kullanan Mobilya-Dekorasyon Firmalarının Sorunları; Bolu Örneği(2020) Köksal, Süheyla Esin; Kelleci, OrhanYonga levha ve MDF endüstrisi ülkemizde mobilya sanayisine hammadde sağlayan temel endüstri kolları arasında yer almaktadır. Masif malzemelere göre maliyetlerinin daha düşük ve tedariğinin kolay olması ülkemizde mobilya-dekorasyon atölyelerinin mobilya üretiminde yonga levha ve MDF’ye yönelmelerini sağlamıştır. Bu çalışmada Bolu-Merkez ve Mudurnu’da faaliyet gösteren 20 adet küçük ve orta büyüklükteki mobilya-dekorasyon firması değerlendirilerek nitel bir araştırma yapılmıştır. Araştırmada yarı yapılandırılmış mülakat yöntemi kullanılmış, mülakat sonrası dokümanlara içerik analizi uygulanmıştır. İçerik analizi sonucu levha kaynaklı ve sosyo-ekonomik sorunlardan en çok karşılaşılanlar üzerinde durulmuştur. Levha kaynaklı sorunlar içerisinde yoğunluk, boyutsal değişim ve yüzey sorunları dikkat çekerken, sosyo-ekonomik sorunlar içerisinde fiyatlar ve tedarikçiler ön plana çıkmıştır. Mobilya üreticisi firmalar levhalarda en çok yoğunlukların düşük, fiyatların yüksek olmasından şikâyetçi olduklarını belirtmişlerdir. Firmaların bayilere bağımlı oldukları, levha tercihi konusunda bayilerin kendilerine sunduklarının dışına çıkamadıkları görüşmeler sonucunda tespit edilmiştir. Ayrıca şikâyetlerinin bayilerce ciddiye alınmadığı, sorunlarının çözümü konusunda umutsuz oldukları sonucuna varılmıştır.Öğe Yüzey Tabaka Yonga Oranının Yonga Levha Özelliklerine Etkisi(2017) İstek, Abdullah; Kurşun, Coşkun; Aydemir, Deniz; Köksal, Süheyla Esin; Kelleci, OrhanBu araştırmada, yonga levha üretiminde ürün kalitesini ve maliyeti etkileyen faktörlerden biri olan, yüzey (üst-alt) tabaka yonga oranlarının levha özellikleri üzerine etkisi incelenmiştir. Test örnekleri Yıldız Entegre Mudurnu tesisinde üretim hattı kullanılarak üretilmiştir. Çalışmada üretilen 3 katlı yonga levhalarda üst-alt yüzey tabaka yonga oranları birinci gurup deney levhaları için % 18,5-18, ikinci gurupta % 18-17,5, üçüncü gurupta % 17,5-17 ve dördüncü gurupta ise % 17-16,5 olacak şekilde seçilmiştir. Üretilen deney levhalarının fiziksel ve mekanik özellikleri, ilgili standartlara göre belirlenerek değerlendirilmiştir. Testler Yıldız Entegre Mudurnu tesislerinde bulunan laboratuvarlarda yapılmıştır. Elde edilen sonuçlara göre su alma ve kalınlığına şişme değerleri ile vida tutma direncinin yüzey tabaka kalınlığına bağlı olarak diğer özelliklerden daha fazla etkilendiği ve en uygun % 18,5-18 alt-üst tabaka oranına sahip levhalarda olduğu belirlenmiştir. Diğer özelliklerin ise anlamlı olarak değişmediği tespit edilmiştir. Dolayısıyla, yonga levha kullanım alanları dikkate alınarak üretim şartlarının revize edilebileceği kanaatine varılmıştır. Rutubetli ortamlar için üretilecek yonga levhaların yüzey yonga kullanım oranının daha yüksek, kuru şartlarda genel amaçlı levha üretimleri için yüzey tabaka kalınlıklarının daha düşük tutulabileceği belirlenmiştir
