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Öğe Bambudan nanofibril selüloz eldesi(2019) Ermeydan, Mahmut Ali; Aykanat, OnurBambu tropikal iklim etkisi altında bulunan alanlarda en önemli doğal kaynaklardan birisidir. Diğer lignoselülozik kaynaklarla karşılaştırıldığında yüksek verim ve düşük maliyete sahiptir. Nanoselülozun yüksek mekanik kuvveti, biyouyumluluğu, yüksek yüzey alanına sahip olması kompozit, gıda ve eczacılık gibi alanlarda kullanılma potansiyelini ortaya çıkarmış, ucuz kaynaklardan doğru metotlarla üretilmesi önem kazanmıştır. Bu çalışmada, ülkemizde de bulunabilen Forgesia nitida bambu türünden sülfürik asit yöntemiyle görünen ortalama 200 nm çaplarında selüloz nanofibrilleri elde edilmiştir. Öncelikle bambu selüloz liflerini izole etmek için sokslet ekstraksiyon yöntemiyle yağsı maddeler ve karışımda çözünen safsızlıklar sikloheksan (2:1) etanol kullanılarak 12 saatte ayrılmıştır. Alkali işlem için %8’lik potasyum hidroksit kullanılarak lignin ve hemiselüloz uzaklaştırılmıştır. Katı madde %10’luk asetik asit çözeltisiyle nötralize edilmiştir. Daha sonra TAPPI metoduna göre sodyum klorit ile tekrar ağartma işlemi uygulanmıştır. Selüloz nanofibrilleri 6,5M sülfürik asit çözeltisiyle 2 saatte 60°C’de reflaks yapılarak üretilmiştir. Nanofibrillerin kimyasal özellikleri FTIR spektroskopisi, termal özellikleri TGA-DTG analizi, morfolojik özellikleri de ışık mikroskobu ile incelenmiştir.Öğe Chemical Modification of Spruce Wood with Combination of Mesyl Chloride and Poly (ε-caprolactone) for Improvement of Dimensional Stability and Water Absorption Properties(Kastamonu Univ, Orman Fak, 2016) Ermeydan, Mahmut AliSustainability is an important issue for materials production which can be provided by using renewable resources such as wood. Wood is a natural material with excellent mechanical properties. However, humidity changes negatively affect wood's dimensional stability. Water repellence and dimensional stability can be both improved by inserting hydrophobic molecules inside wood cell walls. In this study, a two-step modification were carried out by grafting a biodegradable polymer poly(epsilon-caprolactone) (PCL) onto the pre-treated wood cell walls by mesyl chloride. Confocal Raman imaging and spectroscopy were used to show the distribution of mesyl groups and poly(epsilon-caprolactone) within cell walls. The morphology of modified wood cell walls was monitored by scanning electron microscopy. Physical tests showed that the poly(epsilon-caprolactone) grafted wood has significantly better dimensional stability and water repellence compared to references.Öğe Chemical Modification of Spruce Wood with Combination of Mesyl Chloride and Poly (?-caprolactone) for Improvement of Dimensional Stability and Water Absorption Properties(2016) Ermeydan, Mahmut AliMalzemelerin üretiminde önemli bir konu olan sürdürülebilirlik, ahşap gibi yenilenebilir kaynaklardan elde edilen malzemeler kullanılarak sağlanabilir. Ahşap mükemmel mekanik özelliklere sahip doğal bir malzemedir. Ancak, ortamdaki nem değişimleri ahşabın boyutsal kararlılığını olumsuz etkiler. Hem su iticilik hem de boyutsal kararlılık ahşap hücre çeperi içine hidrofobik moleküller sokulmasıyla arttırılabilir. Bu çalışmada, iki aşamalı bir modifikasyonla önceden mesil klorür ile hidrofobize edilmiş ahşap hücre çeperleri içine biyolojik olarak bozunabilir bir polimer olan poli(?-kaprolakton) (PCL) aşı polimerizasyonuyla bağlandı. Konfokal Raman görüntüleme ve spektroskopisi tekniğiyle ahşap hücre çeperleri içindeki mesil grupları ve poli(?-kaprolakton) dağılımını gösterildi. Modifiye edilmiş ahşap hücre çeperlerinin morfolojisi taramalı elektron mikroskobu ile gözlemlendi. Fiziksel testler sonucunda poli(? kaprolakton) ile aşılanmış ahşabın referanslara göre önemli ölçüde daha iyi boyutsal kararlılığa ve su iticiliğe sahip olduğu gözlendiÖğe Effect of process variations of polycaprolactone modification on wood durability, dimensional stability and boron leaching(Walter De Gruyter Gmbh, 2019) Ermeydan, Mahmut Ali; Kartal, Zeynep Nur; Dizman Tomak, EylemIn this study, in situ graft polymerization of epsilon-caprolactone (CL) was studied for its potential to limit boric acid (BA) leaching from wood, and to increase the dimensional stability and biological durability of wood against Coniophora puteana and Trametes versicolor fungi. For this purpose, CL monomer with/without BA was impregnated into wood, and the monomer was polymerized in wood cell walls using various methods and combinations of reactants. It was found that biodegradable polycaprolactone (PCL) grafting at high monomer concentrations could inhibit fungal degradation of wood cell walls, as well as improve the dimensional stability of wood up to 55% and reduce water uptake (WU) by about 50%. However, inductively coupled plasma-optical emission spectrometry (ICP-OES) analysis revealed that in situ graft polymerization of CL is not an effective method to prevent BA leaching from wood.Öğe Evaluation of dimensional stability, weathering and decay resistance of modified pine wood byin-situpolymerization of styrene(Taylor & Francis Inc, 2020) Ermeydan, Mahmut Ali; Babacan, Mert; Dizman Tomak, EylemIn this study, polystyrene modified Scots pine (Pinus sylvestrisL.) wood was investigated upon artificial weathering, decay resistance, dimensional stability and water uptake properties. Polystyrene modification was carried out on pretreated wood by immersion of wood into styrene monomer and further polymerization. The resistance of modified wood against cycles of UV and water exposures was examined by artificial weathering test for 672 hours, and decay resistance was evaluated by attacks ofConiophora puteanaandTrametes versicoloron the samples. During the artificial weathering, color and surface roughness of the samples, and macroscopic changes were determined periodically. Changes in the surface chemistry and morphology of the weathered samples were investigated by ATR-FTIR and SEM, respectively. It was proven that polystyrene effectively protected pine samples from both fungi even after leaching procedure, but it was more effective in preventingC. puteanaattacks thanT. versicolorattacks. As a result of artificial weathering, the surface of all samples was darkened. However, changes in color and roughness as well as crack formations of the modified sample surfaces were found less than those of the untreated samples. Polystyrene also provided considerable improvement on dimensional stability, as well as water repellence of wood.Öğe An investigation of surface properties of thermally modified wood during natural weathering for 48 months(Elsevier Sci Ltd, 2018) Dizman Tomak, Eylem; Ustaomer, Derya; Ermeydan, Mahmut Ali; Yildiz, SibelWeathering period and exposure conditions can affect the degradation rate of wood surfaces. Longer weathering exposure periods are more reliable for end-use performance evaluations, and therefore it is desirable to investigate the role of long exposure periods on wood properties. This study aimed to investigate the effect of thermal modification on surface composition, roughness and color of ash, iroko, Scots pine and spruce wood species during natural weathering in East Black Sea Region of Turkey for 48 months. All measurements were performed at 6 month intervals. Regarding the results, surface roughness increased as the weathering period increased. Surface quality and color stability of the samples were enhanced with the thermal modification for all wood species, and those properties were much better for hardwoods than softwoods. FTIR data showed that changes in surface composition of thermally modified and unmodified wood were so high even at the first weathering exposure period. Thus, thermal modification may not be an effective protection method in long term outdoor conditions if the surface appearance and color stability is required.Öğe A methodological approach to epsilon-caprolactone modification of wood(Taylor and Francis, 2022) Ermeydan, Mahmut Ali; Cambazoglu, Merve; Dizman Tomak, EylemDue to increasing environmental awareness, in recent years the research on classical wood preservation by hazardous impregnation chemicals has been shifted to more environmentally friendly chemical modification methods with organic molecules/polymers. The chemical modification processes rely on the replacement or blockage of wood hydroxyl groups with generally hydrophobic molecules, thereby improving the dimensional stability, water repellency and biological resistance of the wood. This study investigates in situ polymerization of epsilon-caprolactone to form poly(epsilon-caprolactone) (PCL), a biodegradable polymer, which was grafted to the wood cell walls of both Scots pine (Pinus sylvestris L.) and spruce wood (Picea orientalis L.). Wood modification by in situ polymerization of epsilon-caprolactone has been studied so far in order to be an alternative modification approach to obtain improved wood properties, such as good dimensional stability and improved water resistance without reducing mechanical properties considerably. In the light of previous studies, the current work proposes a methodological approach to epsilon-caprolactone modification in two aspects: (i) the effect of catalyst (tin(II) 2-ethylhexanoate) amount on wood properties (i.e., swelling (S), anti-swelling efficiency (ASE), water uptake (WU), mass loss (ML)) (ii) the effect of oven or solvent curing of epsilon-caprolactone on wood properties (i.e., S, ASE, WU, ML, compressive strength parallel to the grain, and chemical components). By these approaches, an optimum catalyst amount was determined, and an alternative method (oven-curing) which may be more economic by enabling the re-use of the waste chemical was evaluated in comparison to the method of epsilon-caprolactone modification in prior publications (solvent-curing).Öğe Modification of spruce wood by UV-crosslinked PEG hydrogels inside wood cell walls(Elsevier Science Bv, 2018) Ermeydan, Mahmut AliChemical modification methods provide wood materials with longer service-life specifically for outdoor utilization by fixing impregnated reagents via covalent bonding into wood cell walls. In this study, poly(ethylene glycol) (PEG) diacrylate (PEGdA) was impregnated in spruce wood and cured via UV-polymerization to form poly(ethylene glycol) (PEG) hydrogel inside wood cell walls. The synthesis was performed in two steps: vacuum impregnation of PEGdA macromonomers and initiator into wood and subsequent crosslinking via UV-polymerization in water media. The resulting hydrogel modified wood cell walls (PEG-m-CW) were characterized by confocal Raman microscopy and spectroscopy, emission scanning electron microscopy, and equilibrium moisture content test. Results show that PEG hydrogels are formed deep inside the wood tissue structure: the polymer is distributed in both latewood and earlywood cell walls, and latewood lumina are filled due to macromonomer blockage. This process allows straightforward, highly practical synthesis of hydrogel in water media and has great potential as a modification method to eliminate specific disadvantages of wood.Öğe A natural flavonoid treatment of wood: artificial weathering and decay resistance(Springer, 2020) Dizman Tomak, Eylem; Ermeydan, Mahmut AliIn this study, a natural flavonoid, chrysin, was used as a wood impregnation agent and evaluated in terms of artificial weathering and decay resistance of wood. For this purpose, Scots pine samples were impregnated with chrysin after tosylation pre-treatment and, then, exposed to artificial weathering for 672 h. Color, surface roughness, contact angle and macroscopic changes were recorded during the test period. Furthermore, surface chemical components and morphological changes were evaluated with ATR-FTIR and SEM, respectively. Decay resistance of samples was assessed using a brown-rot fungus (Coniophora puteana) and a white-rot fungus (Coriolus versicolor) for both leached and un-leached samples. In the results, chrysin impregnation was found efficacious in preventingC. puteanaattack. However, a proper protection was not ensured againstC. versicolorattack. Tosylation was effective in resisting decay by both fungi, but it was not effective in decreasing weathering degradation on the wood surface as chrysin impregnation did. Chrysin decreased color changes and surface roughness. In addition, surface hydrophobicity increased, and lignin degradation decreased with chrysin impregnation. Cracks on treated samples seemed to be an important disadvantage after exposure to weathering agents. Results of chrysin impregnation gave some promising results to improve service life of non/low-durable wood species in outdoor use.Öğe A Natural Flavonoid, Chrysin, Improving Wood Properties via Impregnation(North Carolina State Univ Dept Wood & Paper Sci, 2019) Ermeydan, Mahmut AliA broader utilization of wood can be achieved by eliminating its drawbacks such as low dimensional stability with changing moisture content and low durability against various bio-organisms. Heartwood formation is nature's solution that functions through biosynthesis and accumulation of some phenolic compounds in the cell walls, leading to more durable and stable wood. In this study, a natural flavonoid molecule, chrysin, was used to improve Scots pine wood properties. Hydrophobic chrysin was impregnated into wood after a pre-treatment. The chrysin modification reduced the water uptake of the wood cell walls by up to 33% and increased the dimensional stability of the Scots pine by up to 30%. Infrared spectroscopic analysis revealed the chemical characterization of the bio-inspired modification. In contrast to the many modification methods that establish covalent bonds between hydroxyl groups of wood polymers, chrysin was bulked into wood cell walls and stabilized by intermolecular interactions.Öğe Natural weathering of sixteen wood species: Changes on surface properties(Elsevier Sci Ltd, 2021) Arpacı, Şebnem Sevil; Dizman Tomak, Eylem; Ermeydan, Mahmut Ali; Yildirim, IbrahimIn this study, natural weathering behavior of sixteen different wood species was investigated under the same conditions in order to clarify the resistance against outdoor degrading agents regarding wood color, gloss, surface roughness and surface chemistry. For this purpose, American walnut, ash, cherry, oak, maple, teak, mazel, beli, limba, anigre, tulip, sapele, walnut, eucalyptus, beech and pine samples were exposed to weathering agents on above ground test equipment for a year in Bursa, Turkey, and 36 periodic measurements were carried out from the surfaces during the exposure period. The results showed that the darkest and the greatest color change were found on the surfaces of pine, maple and tulip samples while the least color change was observed on walnut, A. walnut and oak samples. The surface roughness, crack formations and degradation of surface components increased with the increase in exposure period. Gloss property had a tendency to increase on some species such as teak, sapele, walnut, A. walnut, limba and beli while the others lost the gloss, and had a paler surface than the initial stage. In accordance with the color and roughness measurements, FTIR spectra proved that lignin degradation continued on the exposed surfaces during 3 months of natural weathering for all species. Correlation analysis showed that wood species with high density had more stability against color changes. However the roughness and gloss showed nonsignificant correlation between density of samples. (C) 2020 Elsevier Ltd. All rights reserved.Öğe Observation of triple helix motif on electrospun collagen nanofibers and its effect on the physical and structural properties(Elsevier Science Bv, 2018) Buerck, Jochen; Aras, Onur; Bertinetti, Luca; Ilhan, Caner A.; Ermeydan, Mahmut Ali; Schneider, ReinhardCollagen is a very popular natural biomaterial due to its high biocompatibility and bioactivity. Electro-spinning is currently the only technique that allows the fabrication of continuous fibers with diameters down to a few nanometers. In order to regenerate collagen in the forms of nanofibers, it is necessary to dissolve it in suitable solvents. The solvents and electrospinning process cause unfolding of collagen nanofibers. It is proposed that acidic solvents preserve better the natural structure of collagen fibers. In this paper, the structures of collagen nanofibers were examined by using circular dichroism (CD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Raman spectroscopy, differential scanning calorimetry (DSC) and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) methods in order to test this hypothesis. The increase in PP-II fraction, representing the triple helix structure in collagen, that was observed in CD analysis of HAc derived collagen nanofibers, for the first time was successfully confirmed and illustrated by using SEM and TEM methods. Furthermore, CD revealed the mostly detrimental effect of stabilization conditions such as heat, vacuum and UV treatment on the secondary structure of the collagen nanofibers. (C) 2017 Elsevier B.V. All rights reserved.Öğe Poly(ε-caprolactone) grafting into Scots pine wood: improvement on the dimensional stability, weathering and decay resistance(Springer Science and Business Media B.V., 2021) Ermeydan, Mahmut Ali; Babacan, Mert; Tomak, Eylem DizmanWood modification treatments by substitution or blocking of wood hydroxyl groups with hydrophobic molecules are some of the novel approaches that may improve dimensional stability, weathering and decay resistance of wood. In this study, the Scots pine (Pinus sylvestris L.) wood was modified by ring opening polymerization of ε-caprolactone to investigate the artificial weathering and decay resistance. In total, 672 h of artificial weathering was applied on modified wood by exposure of UV-light and water cycles. Additionally, decay test was carried out by using Coniophora puteana and Trametes versicolor fungi on the samples after leaching procedure. After weathering, the color change and contact angle measurements, as well as macroscopic observations revealed that the modified wood had significantly better surface properties than reference wood. FT-IR and SEM analysis proved that there was still polycaprolactone on the weathered surface with some minor crack formations of wood structure. The polycaprolactone modification effectively protected wood against decay even after leaching. This study also demonstrates that the polycaprolactone modification can provide a significant improvement on dimensional stability, as well as water repellence of Scot pine wood. Graphic abstract: [Figure not available: see fulltext.]Öğe Wood property improvement of siberian pine by combination of boric acid impregnation and insitu polymerization of Ԑ-caprolactone(2019) Ermeydan, Mahmut Ali; Dizman Tomak, Eylem; Kartal, Zeynep NurWood is an excellent engineering material with its light weight and high mechanical properties. However, it is susceptible to biodegradation due to its hygroscopic nature and chemical composition that limits both its indoor and outdoor usage. Boron compounds which are known as eco-friendly wood preservatives have limited utility at outdoor conditions since they are easily leached out from wood by water. The aim of this study is to prevent boron leaching by creating a polymer network that encapsulates boron compound inside the wood cell walls, thus decay resistance, dimensional stability and water repellence are improved. In the study, Siberian pine samples were impregnated with 1% boric acid in DMF(N,N-Dimethylformamide) and further ?-caprolactone monomer (1% SnOct2 as initiator) mixture for further in-situ polymerization were carried out in the oven at 150°C for 3 hours. Prior to decay testing, leaching test was conducted in order to evaluate any loss in effectiveness in decay resistance against to C. puteana and C. versicolor attack due to possibility of boron leaching from wood. The results showed that leached samples had lower weight loss than unleached samples after C. puteana attack, however, the weight loss by C. versicolor attack increased in leached samples. Decay resistance of treated samples was found to be 7-99% in comparison with references. Boric acid and polymer combination increased dimensional stability (25% ASE), and water repellence (15%) of wood compared to references without deformation. This method showed that curing may be an alternative for wood modification with in-situ polycaprolactone polymerization in order to use hazardous solvent media for polymerization.