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Öğe Application of acrylic-based varnishes reinforced with nano fillers for conservation of weathered and worn surfaces of the historical and cultural wooden buildings(Elsevier France-Editions Scientifiques Medicales Elsevier, 2022) Aksu, Soner; Kelleci, Orhan; Aydemir, Deniz; İstek, AbdullahThe aim of this study was to investigate the surface protection effects of acrylic-based varnishes including TiO2 and Al2O3 nano-fillers in the conservation process of naturally aged and worn surfaces of historical and cultural wooden structures. The varnishes were applied to the wood surfaces with a brush and the varnish-coated samples were artificially aged in a weathering cabin. The changes in the surfaces of the samples were evaluated according to color change, micro hardness, abrasion tests, scratch tests, surface durability, and surface characterization via scanning electron microscopy (SEM). The thermal properties and morphological characterization of the varnishes with nano-fillers were also determined, and ultraviolet-visible (UV-vis) and FTIR analyses were performed. The results showed that the micro hardness, abrasion, and scratch values of the varnishes were not statistically significant. However, the values of the varnishes with TiO2 were determined to be slightly higher than those of the varnishes with Al2O3. The surface durability of the neat varnish was significantly improved by adding the nano-fillers. With the addition of the nano-fillers, the SEM revealed reduced thickness of the varnishes on the surfaces of the wood samples. The thermal properties, optical properties with UV-vis, and morphological structure of the neat varnish were improved by adding the nano-fillers, whereas the FTIR detected no difference in the bonding of the varnishes. The UV spectra of TiO2 and Al2O3 generally showed a peak at 354nm and 210nm wavelengths, which means that they exhibited good absorbance in the UV region. The results indicated that adding nano-fillers to the neat varnish could generally improve the outdoor performance and lifetime of historical and cultural wooden structures. (C) 2022 Elsevier Masson SAS. All rights reserved.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 THE INFLUENCE OF ROAD TRAFFIC AND INDUSTRIAL PLANT-INDUCED AIR POLLUTION ON THE PHYSICAL, MECHANICAL, CHEMICAL AND MORPHOLOGICAL PROPERTIES OF THE BLACK PINE WOOD(Univ Bio-Bio, 2024) Koksal, Suheyla Esin; Kelleci, Orhan; Tekingunduz, Gul; Aydemir, DenizRoad traffic pollution and industrial plant-induced pollution affect negatively the development of forest trees. How forest trees are affected by their growing environment is important for sustainable environment. The study aimed to investigate the physical, mechanical, chemical, and morphological properties of the Pinus nigra (black pine) tree which grows under different conditions. Tree samples were chosen from three different lands where were inside the forest (O), near the roadside (Y), and near the factory (F). It was studied whether there were any significant differences among the O, Y and F in terms of their wood properties such as physical, mechanical, chemical, and morphological. As a result, the O samples demonstrated more regular annual ring structure. On the other hand, it was observed that the Y samples had longer and wider tracheid cells. In addition, Y samples had better mechanical strength than O and F. Environmental pollution caused the presence of some different elements (chlorine and iron) in Y and F. As a result, it was determined that the trees growing near the roadside or near industrial plants have significant differences from forest trees which are far away from pollutions. It is possible to say that Pinus nigra (black pine) is resistant to environmental stress. For this reason, it can be recommended to use it as a barrier to reduce air pollution on the roadsides.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 Thermoplastic composites of polypropylene/biopolymer blends and wood flour: Parameter optimization with fuzzy-grey relational analysis(SAGE Publications Ltd, 2022) Kelleci, Orhan; Aydemir, Deniz; Altuntaş, Ertuğrul; Kurt, Rıfat; Yörür, HüseyinIn this study, blends of polypropylene (PP) with polylactic acid (PLA) and polyhydroxybutyrate (PHB) biopolymers and wood flour were prepared, and Fuzzy and Grey Multi-Criteria Decision-Making (MCDM) methods were used to determine the blends with the best properties. The physical, mechanical, thermal, structural, and morphological properties of the composites were determined. The obtained results showed that PLA and wood flour generally improved the mechanical properties of the PP composites. However, wood flour did not exhibit a homogeneous distribution in the matrix. The density of the composites generally increased with the addition of both PLA and PHB. X-ray diffraction analysis showed that the crystallinity index of the composites generally decreased due to the low crystallinity of biopolymers. Thermal stability did not change with the addition of PLA and PHB, but the addition of wood increased thermal stability. According to the MCDM analysis, both Fuzzy and Grey results were similar.Öğe Wood flour-reinforced green composites: Parameter optimization via multi-criteria decision-making methods(Springer, 2022) Kelleci, Orhan; Aydemir, Deniz; Altuntaş, Ertuğrul; Kurt, Rıfat; Öztel, Ahmet; Yörür, HüseyinThe aim of this study was to investigate the physical, mechanical, morphological, structural, and thermal properties of polylactic acid (PLA) and polyhydroxybutyrate (PHB) biopolymer composites reinforced with thermally treated wood flour and to determine the formulations having optimum properties by using multi-criteria decision-making (MCDM) methods. As a filler, Scots pine wood flour (untreated and thermally treated at 212 degrees C) was used at the loading rates of 10% and 30%. The samples were prepared using a twin-screw extruder and then by compression molding. The results showed that the addition of both thermally treated and untreated wood flour slightly increased the density of the composites. According to the color measurement, the thermally treated wood composites were slightly darkened in appearance. In the composites, with both wood fillers, the water absorption and thickness swelling ratios had increased during the 20-250 days of water exposure. Lower water absorption and thickness swelling rates were found for the composites with thermally treated wood filler compared to the other composites. The wood fillers generally lowered the mechanical properties of the PLA and PLA/PHB composites, with the PHB composites as the exception. However, the tensile modulus and Izod impact strength of the composites generally increased with the addition of wood fillers. Morphological examination performed by scanning electron microscopy (SEM) indicated that the wood flour was mostly homogeneously distributed in the matrix, which improved the mechanical properties of the composites. Thermogravimetric analysis (TGA) showed that the addition of wood filler to the neat biopolymers as a rule did not provide significant improvement in the thermal stability; however, the fillers increased the thermal stability of neat PHB. The Fourier-transform infrared (FTIR) spectroscopy detected no differences in the chemical structure of the composites. The X-ray diffraction (XRD) results indicated a general increase in the crystallinity with the addition of wood fillers to the neat biopolymers and the blends. All the findings were subjected to MCDM analysis to determine the formulation having the optimum properties and the results showed this to be the neat PLA sample.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
