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Öğe Application of modified cellulose nanofibrils as coating suspension on recycled paper using size press(Walter De Gruyter Gmbh, 2021) Fidan, Hakan; Tortuoglu, Ayhan; Tutus, Ahmet; Poyraz, Bayram; Arslan, Recai; Sertkaya, Selva; Killi, UfukCellulose based nanomaterials have the great potential to be applied to paper as bulk additive or coating material to improve overall final properties, especially in secondary fiber. In the present work, the effect of applying different kinds of cellulose nanofibrils (CNF) to papers obtained from recycled fibers using size press on physical, mechanical and barrier properties was investigated and compared with the sole use of starch as coating material. The coating process of CNF was carried out by the addition of size press grade starch to coating suspension. As a cellulose source, wheat straw was evaluated and CNF was obtained through oxidative and enzymatic pretreatments. Results indicate that starch/CNF suspension improves the overall paper properties. As a result of the deposition of coating suspension contains of 4 % wt. periodate-oxidized CNF onto paper surface, tensile and burst indices of papersheets increased as 52.2 % and 194.4 %. Significant decreases were observed in air permeability as 69.8 %. Compression tests also have been conducted to evaluate papersheets end-use properties. In comparison to the other pretreated CNF, due to is lower viscosity, applying periodate-oxidized CNF as size press significantly increased the mechanical properties of the papers fabricated from the recycled pulps.Öğe Atık sularda boya giderimi için fonsiyonellenmiş nanoselüloz esaslı adsorbanlar(2021) Arslan, Recai; Tozluoğlu, Ayhan; Sertkaya, Selva; Fidan, Hakan; Küçük, SibelSon yıllarda, dünya genelinde artan nüfus ile birlikte tarımsal ve endüstriyel faaliyetler giderekartmıştır. Bu faaliyetler sırasında ortaya çıkan organik maddeler, inorganik anyonlar, toksik ağırmetaller, zehirli gazlar vb. birçok kirletici çevreye salınmakta ve özellikle sularda önemli derecedekirlilik sorunlarına yol açmaktadır. Bu nedenle çevre dostu ve uygun maliyetli arıtma teknolojilerineihtiyaç duyulmaktadır. Atık sularda kullanılan adsorpsiyon işlemi çevre dostu arıtma teknolojilerindenbiridir. Çeşitli doğal kaynaklardan elde edilebilen selülozik maddeler adsorbanlar olarakkullanılabilmektedir. Atık sularda bulunan organik kirleticiler ve ağır metal iyonlarının adsorpsiyonkapasiteleri kimyasal işlemlerden etkilenmekte olup, modifiye edilmiş selülozun modifiye edilmemişselüloza göre daha yüksek adsorpsiyon kapasitesi sergilediği bilinmektedir. Bu derlemede, literatürdeyer alan çeşitli nanoselüloz esaslı adsorbanların, özellikle atık sularda bulunan boyalarınuzaklaştırılmasında sergiledikleri adsorpsiyon kapasiteleri ve bu adsorbanların modifikasyonlarısonrasında yapılarının karakterizasyonunda kullanılan FTIR ve SEM analizleri incelenmiştir.Nanoselüloz esaslı adsorbanların atık sulardaki boyaların uzaklaştırılmasında iyi bir potansiyelsergilediği görülmektedir. Çevre kirliliğini minimuma indirmek için ucuz ve daha etkili selüloz esaslıadsorbanların modifikasyonlarla geliştirilebileceği düşünülmektedir.Öğe Göl kamışından (Phragmites australis) biyolojik ve kimyasal ön muamele sonrası biyoetanol üretimi(Düzce Üniversitesi, 2017) Fidan, Hakan; Tozluoğlu, AyhanBu çalışma, göl kamışının biyolojik ve kimyasal ön muamele sonucu biyoetanol üretimi için uygunluğunu belirlemeyi amaçlamıştır. Göl kamışının etanole dönüşümünde, sodyum hidroksit (NaOH), hidrojen peroksit (H2O2), sodyum borhidrür (NaBH4), boron oksit (B2O3) ve sülfürik asit (H2SO4)'in etkileri kimyasal ön muamele ile saptanmıştır. Glukan dönüşüm oranlarında en yüksek verim (%79.7) NaOH muamelesinde, sonrasında sırasıyla NaBH4 (%74.1), H2O2 (%71.9), mantar ön muamelesi (%69.4), B2O3 (%65.5) ve H2SO4 (%46.1) muamelelerinden alınmıştır. Muamele edilmemiş göl kamışından elde edilen en yüksek etanol verimi (13.2 g/100 g) ve hesaplanmış en yüksek teorik verim (%85.3) NaOH ile ön muamele edilmiş örneklerde gözlemlenmiştir. Mantar ve NaBH4 ile ön muamele edilmiş örnekler sırasıyla 10.6 ve 12.3 g/100 g etanol eldesi vermişlerdir (muamele edilmemiş göl kamışına kıyasla). Bu çalışmanın sonuçları ekonomik uygunluk ve çevresel avantajlarından dolayı mantar ön muamelesinin göl kamışından biyoetanol üretimi için oldukça uygun olduğunu göstermiştir.Öğe Nanocellulose: Sustainable biomaterial for developing novel adhesives and composites(Elsevier, 2022) Candan, Zeki; Tozluoğlu, Ayhan; Gönültaş, Oktay; Yıldırım, Mert; Fidan, Hakan; Alma, Mehmet Hakkı; Salan, TufanCellulose is one of the most ubiquitous and abundant natural biopolymer in the world. Nanocellulose are nanoscale cellulose-based materials isolated from trees, annual plants, agricultural residues, and algae or generated by bacteria or tunicates. Among many other sustainable nanomaterials, nanocellulose is drawing increasing interest for use in environmental remediation technologies due to its attractive properties such as excellent mechanical properties, high surface area, rich hydroxyl groups for modification, and natural properties with 100% environmental friendliness. Nanocellulose can be classified as micro/nanofibrillated cellulose (MFC/NFC), micro/nanocellulose crystals (MCC/NCC), and bacterial cellulose (BC). Nanocellulose has an existing potential as reinforcements in polymers, composite materials, and nanocomposites. Nanocellulose can be used in a variety of products such as automobile, aircraft, electronics, medical, textiles, food, optics, packaging materials, gels, composites, pharmaceuticals, bone replacement, dental products, tissue engineering, construction, coatings, wood-based composite materials, paints, papermaking, and cosmetics. © 2022 Elsevier Ltd. All rights reserved.Öğe Printability of variative nanocellulose derived papers(Springer, 2021) Ozcan, Arif; Tozluoglu, Ayhan; Arman Kandirmaz, Emine; Tutus, Ahmet; Fidan, HakanThe printability properties of the paper can be increased by some processes applied to the surface. The use of non-recyclable materials derived from petroleum is decreasing day by day, and the demand for recyclable materials obtained from renewable sources is increasing. These materials include cellulose derivatives, starch types and polyvinyl alcohol. The materials ratios, sizes, physical and chemical properties of these materials used in the processes applied to the paper and the content of the paper will affect the strength of the paper as well as change the surface properties and significantly affect the printability. The aim of this study is to obtain better printability properties by improving the paper surface with CNF/CNF-OX coating. In this study, fluting and core board papers coated with different amounts of cellulose nanofiber (CNF)/cellulose nanofiber-oxidized (CNF-OX) were produced. Surface properties, contact angle, surface energy, color and gloss of the produced papers were measured by optical microscope, goniometer, spectrophotometer and glossmeter. The papers were printed with the IGT C1 offset printability tester. As a result, in terms of printability, it was determined that CNF/CNF-OX coated papers have smoother surfaces and give better results in terms of both gloss properties and printability. [GRAPHICS] .Öğe Reinforcement Potential of Modified Nanofibrillated Cellulose in Recycled Paper Production(North Carolina State Univ Dept Wood & Paper Sci, 2021) Tozluoglu, Ayhan; Fidan, Hakan; Tutus, Ahmet; Arslan, Recai; Sertkaya, Selva; Poyraz, Bayram; Gucus, Mehmet OnurhanThe influence of nanofibrillated cellulose (NFC) was investigated as a reinforcing agent to improve strength properties of papersheets fabricated from recycled pulp fibers of mixtures of old newspapers, old magazines, and old corrugated cardboards. To determine the effects of the NFC on the mechanical and physical properties of the recycled pulp papers, cellulose nanofibrils (NFC) were isolated from wheat straw, pretreated chemically and enzymatically (NFC-OX), and then added to the bulk suspensions of papermaking pulp slurries at various percentages. The electrokinetic and drainage properties of the pulps and the mechanical and physical properties of the papersheets were analyzed and compared. As expected, the addition of NFC/NFC-OX significantly increased the strength properties of papers. Papers containing 4% of NFC-OX (periodate pretreated) presented higher increases in tensile index (43%) and burst index (59.3%) than other papers. However, a high addition of NFC/NFC-OX increased the water retention, which is undesirable for papermaking. Hence, with optimum selection of NFC/NFC-OX and process conditions, higher mechanical properties could be acquired without increasing drainage rate. Compared to the other pretreated NFC/NFC-OX types, sodium-periodate-oxidized NFC-OX samples significantly increased the mechanical properties of the papers fabricated from the recycled pulps.Öğe ULTRASOUND MEASUREMENT OF EXTERIOR WOOD COATING THICKNESS(Univ Bio-Bio, 2018) Hysek, Stepan; Trgala, Kamil; Fidan, Hakan; Panek, Milos; Lexa, Martin; Bohm, Martin; Veverka, JanThe present paper deals with the measurement of coat thickness on wood using an ultrasonic measurement method. Exterior wood coatings (waterborne acrylate dispersions) with coating film thickness between 80 - 115 mu m were examined. The non-destructive film thickness measurement used a Sursonic ultrasound measuring device, enabling measurement of the thickness of thin films on non-ferromagnetic and simultaneously non-conductive materials. The device also enables measurement of very thin layers of coating films, where the transit time of an ultrasound pulse through the film is shorter than the time width of the pulse. The accuracy of measurement using this measuring device was determined; destructive measurement using a light microscope was chosen as a reference measurement method. Differences in the results measured using the destructive and non-destructive methods were recorded; nevertheless, in most cases, these differences are smaller than the uncertainty of measurement using the light microscope. It can be concluded, therefore, that the results of the two compared methods match over the entire range of thickness of 80 - 115 mu m. The largest differences in the measurement readings from the destructive and non-destructive methods were identified in the range of 97 - 103 mu m.Öğe WATER PERMEABILITY OF EXTERIOR WOOD COATINGS: WATERBORNE ACRYLATE DISPERSIONS FOR WINDOWS(College Publishing, 2018) Hysek, Stepan; Fidan, Hakan; Panek, Milos; Böhm, Martin; Trgala, KamilPermeability of coatings for water and water vapor is an important factor in their wood protective function. In this study, the permeability of coatings in terms of liquid water and water vapor absorption and desorption was measured based on different parts of the standard EN 927. This study evaluated the permeability of commercial coating systems and ascertained effects of coating layering on the coating permeability. For this measurement, six different waterborne acrylate dispersions were used as paint on spruce test samples. The results clearly revealed that liquid water and water vapor uptake were affected by coating film thickness, number of coats, and coating composition (producer). It was ascertained that the type of coating pigmentation affected water absorption of coatings and that with a constant coating film thickness, the number of coats affected water vapor absorption and desorption, but not water absorption. Furthermore, it was observed that the number of coats affected the correlation between the coating film thickness and water vapor absorption and desorption. The values for water vapor absorption were much higher than for liquid water absorption and, unlike the water vapor absorption rate, the water vapor desorption rate was approximately 50% lower.
