Industrial applications of microfibrillated cellulose (MFC) and nanofibrillated cellulose (NFC) have been in use for some time; however, there is a need to improve the production steps and at the same time to obtain better quality products. NFC and MFC were generated from NaBH 4-modified kraft pulp, produced from a red gum tree plant (Eucalyptus camaldulensis). The generated NFC and MFC were characterized by high-performance liquid chromatography, Fourier transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA) and 13 C-nuclear magnetic resonance (NMR). Morphological and viscoelastic properties were investigated by scanning electron microscopy and rheometry, respectively. The storage moduli of biofilms produced from NFC and MFC were investigated by dynamic mechanical thermal analysis (DMTA). Both exhibited mostly identical FTIR spectra. When the spectra were compared with those of NaBH 4-modified kraft pulp, minor shifts were observed due to crystallinity. In NMR spectra, disordered cellulose structures were observed for both NFC and MFC, and these findings were also confirmed by differential scanning calorimetry. Rheology studies revealed that the lowest viscosity was observed with MFC. TGA results showed that NFC degraded earlier compared with NaBH 4-modified kraft pulp. DMTA exhibited that NFC films had about six times higher storage modulus compared with MFC.
In this study, oyster (Pleurotus ostreatus) mushroom was cultivated from hazelnut branches (HB) (Corylus avellana L.), hazelnut husk (HH), wheat straw (WS), rice husk (RH) and spent coffee grounds (CG). Hazelnut branch waste was used for the first time in oyster mushroom cultivation. In the study, mushrooms were grown by preparing composts from 100 to 50% mixtures of each waste type. Yield, biological activity, spawn run time, total harvesting time and mushroom quality characteristics were determined from harvested mushroom caps. In addition, chemical analysis of lignocellulosic materials (extractive contents, holocellulose, α-cellulose, lignin and ash contents) were carried out as a result of mushroom production and their changes according to their initial amounts were examined. In addition, the changes in the structure of waste lignocellulosic materials were characterized by FTIR analysis. As a result of the study, 172 g/kg yield was found in wheat straw used as a control sample, while it was found as 255 g/kg in hazelnut branch pruning waste. The highest spawn run time (45 days) was determined in the compost prepared from the mixture of hazelnut husk and spent coffee ground wastes. This study showed that HB wastes can be used for the cultivation of oyster mushroom (P. ostreatus). After mushroom cultivation processes, holocelulose and α-cellulose content rates decreased while ash contents increased. FTIR spectroscopy indicated that significant changes occurred in the wavelengths regarding cellulose, hemicellulose and lignin components. Most significant changes occurred in 1735, 1625, 1510, 1322 and 1230 wavelengths.
Bu çalışmada, ökaliptus (Eucalyptus camaldulensis) odun yongalarından, ağartılmış kraft hamur lifi elde edilmiştir. Ardından ağartılmış hamur lifi 2,2,6,6-tetrametilpiperidin-N-oksil (TEMPO), Nhidroksiftalimit (PINO) ve periyodat (IO4−) ile modifiye edilmiştir. Sonrasında elde edilen ürünler homojenizatörden geçirilerek nano boyutlara düşürülmüş ve modifiye nanoseluloz elde edilmiştir. Elde edilen modifiye nanoselülozların, kimyasal özellikleri HPLC (High Performance Liquid Chromotography) ve FTIR (Fourier Transform Infrared) ile morfolojik analizleri ise SEM (Scanning Electron Microscopy) cihazları kullanılarak belirlenmiştir. Çalışmada modifikasyonlar sonrasında, moleküler ve amorf yapının değiştiği belirlenmiştir. Periyodat'ın, 2,2,6,6-tetrametilpiperidin-N-oksil ve N-hidroksiftalimit ile karşılaştırıldığında, glukoz üzerinde daha etkin olduğu belirlenmiştir. Morfolojik analizlerde 2,2,6,6-tetrametilpiperidin-N-oksil'in N-hidroksiftalimit'e ve periyodata oranla lif yapısının boyutsal değişiminde daha etkili olduğu gözlenmiştir. Son yıllarda nano seviyelerde yapılan çalışmaların sayısı giderek artış göstermektedir. Çalışmada nano boyutlara sahip nanoselüloz üretimi ve ardından üretilen nanoselülozun modifikasyonu başarıyla gerçekleştirilmiştir. Çalışma sonucunda modifiye nanoselülozların kimyasal ve morfolojik özellikler incelendiğinde, kullanılan kimyasalların nanoselüloz üzerinde farklı etkiler meydana getirdiği belirlenmiştir. Elde edilen bulgular ışığında mevcut çalışmanın literatüre destek sağlayacağı düşünülmektedir.
Cellulose 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.
Kök, sap, saman, yaprak ve kabuk vb. gibi lignoselülozik hammadde kaynaklarından elde edilebilen nanoselüloz, kullanım potansiyeli ile orman ürünleri alanında önemli bir malzemedir. Tarımsal faaliyetler sonucu ortaya çıkar ve sahip olduğu fiziksel, kimyasal ve morfolojik özellikleri ile kullanıldığı nihai ürünlere olumlu etkiler sağlar. Literatürde nanoselüloz üretim yöntemi olarak sıklıkla kullanılan alkali veya asidik üretim yöntemine nazaran enzimatik hidroliz yöntemi daha az araştırılmıştır. Genel olarak, enzimatik hidroliz yoluyla nanoselüloz üretim süreçleri ile selüloz nanofibriller (CNF) üretilirken, enzimatik olmayan işlemler ile kristal nanoselülozlar (CNC) üretilmektedir. Bu çalışmada ilk kez buğday sapından elde edilen soda-NaBH4 ağartılmış kağıt hamuru liflerine iki farklı enzimatik ön muamele (hemiselülaz Pulpzyme HC 2500 ve selülaz Celluclast 1.5 L ticari enzimleri) ve ardından gerçekleştirilen homojenizasyon işlemi ile CNF elde edilmiş, homojenizasyon işlemi sonrası elde edilen CNF’ nin kimyasal, morfolojik, termal ve reolojik özelliklerindeki değişimler incelenmiştir. Enzimatik ön muamele işlemleri sonrasında gerçekleştirilen HPLC analizleri; artan enzim konsantrasyonlarında yapıdan daha fazla miktarda karbonhidratın uzaklaştırıldığını ve yüksek basınç altında gerçekleştirilen homojenizasyon sonrasında alınan SEM görüntüleri liflerin CNF üretiminde homojen bir şekilde nano boyuta indirgendiğini (ortalama 20-50 nm lif çapı) ortaya koymuştur.
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