Browsing by Author "Ateş S."

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Characterization and Comparison of Some Kraft Lignins Isolated from Different Sources
(2023-05-01) Olgun Ç.; Ateş S.
Lignin characteristics are significantly affected by kraft processing and isolation conditions. In the studies carried out in this context, commercial lignins or isolated lignins from industrial black solutions are generally preferred. In this study, in order to conduct more comprehensive research, three lignin samples were isolated from kraft black liquor obtained from laboratory cooking trials of pine, poplar, and wheat straw chips, representing softwoods, hardwoods, and annual plants, respectively, according to efficient pulping studies. In addition, another lignin-containing industrial waste was provided from a pulp mill (OBL). The acidification method was applied for isolating lignin from black liquor samples. After isolating the lignin samples from different sources, they were characterized and compared with the commercially available kraft lignin sample (Indulin AT). Total phenolic groups, carboxyl groups, purity, functional groups, nitrobenzene oxidation products, molecular weight, thermal stability, and element contents were analyzed. The isolated lignin samples (except wheat straw) were as pure as commercial lignin. Since the wheat straw was agricultural waste and an annual plant, inorganic elements such as P, K, and Si were more abundant than in the other samples. However, the polydispersity and molecular weight of all of the isolated lignin samples were higher than those of commercial lignin. Because the ash contents of the lignin samples for pine, poplar, OBL, and indulin AT were between 1 and 3%, they can be used for high-value applications. In particular, despite some disadvantages, wheat straw lignin has greater potential for use in extruders than softwood lignins due to their syringyl content.
Comparison of different chemical pulps from wheat straw and bleaching with xylanase pre-treated ECF method
(2008-01-01) Ateş S.; Atik C.; Ni Y.; Gümüşkaya E.
Different pulping processes, kraft-anthraquinone (AQ), bio-kraft, soda-AQ, ALCELL, and FORMACELL were studied for wheat straw. Fungal pre-treatment with Ceriporiopsis subvermispora, white rot fungi, was applied to wheat straw before kraft-AQ pulping, the so-called bio-kraft process. Fiber properties, carbohydrate contents, FT-IR analyses, strength properties of resultant paper, and bleachability characteristics were included to determine the properties of these pulp samples. In addition, the effects of the xylanase pre-treatment on the subsequent Elemental Chlorine Free (ECF) bleaching process were investigated. The results indicated that kraft-AQ pulps from wheat straw exhibited better characteristics than the other pulp samples with lower kappa number, higher carbohydrate content, higher paper strength properties, and better bleachability. The highest kappa number, viscosity, and fiber coarseness were found for organosolv pulp samples; however, these pulps had the lowest carbohydrate contents and strength values and poor bleaching properties. It was concluded that the fungal pre-treatment of wheat straw with C. subvermispora had a positive effect on the bleachability and gave stronger pulp. There was no clear alteration in the crystallinity index of pulp samples based on the FT-IR results. © TÜBİTAK.
Comparison of properties of cellulose nanomaterials(Cnms) obtained from sunflower stalks
(2021-01-01) Durmaz E.; Ateş S.
This study aimed to investigate the usability of sunflower stalks, which is one of the most significant agricultural residues in Turkey, in the production of cellulose nanomaterials (CNMs). Cellulose nanofibrils (CNFs) and cellulose nanocrystals (CNCs) were produced by using a grinding method and acid hydrolysis, respectively. The average width and length of CNCs were found as 13.91 ± 3.09 nm and 60.44 ± 21.06 nm, respectively. Besides, the average width of CNFs was determined as 15.03 ± 3.68 nm. The crystallinity index of CNFs and CNCs was determined as 82.64% and 83.09%, respectively. Although the main thermal degradation stage of CNCs started at higher temperature than that of CNFs, the latter were more stable than CNCs at high temperatures. Furthermore, the chemical bonds in the raw material, bleached fiber, CNCs and CNFs were investigated with FTIR analysis. Consequently, it was seen that sunflower stalks can be a suitable raw material for the production of CNMs.
Comparison of pulping and bleaching behaviors of some agricultural residues
(2014-01-01) Ateş S.; Deniz İ.; Kirci H.; Atik C.; Okan O.T.
The present study determines the characteristics of bleaching and beating of annual plants and agricultural waste, which constitute important raw material potential for the pulp and paper industry in Turkey. It also examines the effects of this process on several paper properties. Firstly, chemical contents are determined for each raw material and then evaluated for use in the pulp and paper industry. All raw materials studied are found to be suitable for use in the pulp and paper industry, according to the determined chemical content. Secondly, pulp with different properties is obtained and subsequently pretreated with the enzyme xylanase. It is then bleached using the elementary chlorine-free (ECF) method, utilizing the DEpD bleaching sequence, which is both easy to apply and highly effective. The bleaching behavior of each material is then determined. The highest ISO brightness value of 98.3% is obtained using soda-AQ pulps deriving from rye straw. This is followed by wheat straw (92.0%), reed (88.6%), corn stalks (87.6%), and rice straw (87.5%). Each unbleached pulp sample is beaten at a constant 3000 revolutions PFI (9000 rev. for hemp), and changes in freeness properties are determined. The hardest material to beat is hemp fibers, followed by reed, rye, corn, and cotton stalks. The best beatable pulps are rice straw, tobacco, wheat, sunflower, and barley stalks. Paper sheets from both unbleached and bleached pulps are tested.
DNA protection, antioxidant, antibacterial and enzyme inhibition activities of heartwood and sapwood extracts from juniper and olive woods
(2015-08-21) Özkan O.E.; Zengin G.; Akça M.; Baloʇlu M.C.; Olgun Ç.; Altuner E.M.; Ateş S.; Aktümsek A.; Vurdu H.
In this study, DNA protective, antioxidant, antibacterial and enzyme inhibiting properties of methanol extracts obtained from juniper and olive heartwood and sapwood were determined. These extracts were tested by five antioxidant methods (DPPH scavenging, FRAP, CUPRAC, metal chelating and phosphomolybdenum). Generally, heartwood extracts of both species are more efficient for DPPH radical scavenging activity, cupric ion reducing activity, ferric reducing antioxidant power and metal chelating activity than sapwood extracts. When compared to heartwood extracts, sapwood extracts have larger inhibition zone in disk diffusion test. In addition, all extracts showed high antibacterial activity against Staphylococcus aureus. DNA protection of both extracts had a capacity to inhibit the DNA damage arisen from Fenton's reagent. The highest DNA protective activity was observed in juniper sapwood extract with 84%. Furthermore, other extracts also indicated more than 60% of DNA protective activity. Olive wood extracts displayed the strongest enzyme inhibition activities against acetylcholinesterase (AChE) and butyrylcholinesterase (BChE). Although juniper heartwood extracts showed highest anti-amylase, anti-glucosidase and anti-tyrosinase effects, they had no ability for inhibition BChE. The methanol extracts of olive samples demonstrated the most antioxidant activity (DPPH, CUPRAC and FRAP). In addition, juniper samples showed the highest anti-amylase, anti-tyrosinase, metal chelating and DNA protective activity. According to these results, the extracts of juniper and olive wood can be considered as a source of natural bio active agents for dietary, pharmacological and medicinal applications. This research will also serve as a base for future studies about biological activities of wood extracts.
Effect of pressing conditions on some surface properties of HDF laminate parquets
(2016-01-01) Kara M.; Yerlikaya Z.; Ateş S.; Olgun Ç.
In this study, the effects of lamination conditions on some commercialhigh density fiberboard(HDF) panels surface quality characteristics, surface strength, impact resistance test(large diameter ball test), curing degree, scratch resistance, abrasion resistance are investigated. For this purpose, HDF panels are produced from mixture wood fibers(50% black pine and 50% beech wood) as 8.3 mm thickness. After panels sanded to 7.3 mm thickness, laminated at different pressures and times. Ithas been found thathigh pressure and short-term press time conditionshave significant effect on surface strength, impact resistance, and abrasion resistance values. The best surface quality measurements are obtained from A1 group, pressure 340 kg/m² and 13 s pressing time(average of surface strength value of this group is 1.83 N/mm2, impact resistance value is 25.25 N and abrasion resistance value is 3650 revolution), but the lowest value is B3 groups, 320 kg/m² pressure and pressing time of 18 s(average of surface strength of this group is 1.58 N/mm2, impact resistance value is 20 N and abrasion resistance value is 3200 revolutions). Besides production factors of HDF panels and laminating material properties, press operating conditionshave been found to be decisive factors in laminate parquet pressing process for high surface quality.
Effects of Medium Density Fiberboards (MDF) Recycling Methods on Fiber Dimensions and Some Reconstructed Board Properties
(2023-01-01) Olgun Ç.; Ateş S.; Uzer E.
In this study, different methods, including acid hydrolysis (phosphoric and formic acid), thermohydrolysis, and microwave methods were tested for recycling of fiberboards made of 100 % beech and 70 % beech + 30 % pine wood fibers, which are widely sold in the market. The impacts of the using methods on the fibers were investigated with the help of a device that determines the fiber dimensions according to optical principles. In a laboratory setting, test boards were constructed using recycled fibers, and the changes in certain physical and mechanical qualities were studied. As a result, it was determined that recycled fibers obtained from microwave and thermo-hydrolysis fibers could be effectively used in fiberboard production. However, the proportion of fibers, longer than 1.24 mm, was decreased by about 30 % with the phosphoric acid method for MDF samples composed of 100 % beech fiber. The fiberboards could not be obtained from fibers recycled through acid hydrolysis except for phosphoric acid method with 100 % beech fibers.
Evaluation of some plastic wastes as an additive to reinforcing the high density fiberboard (Hdf)
(2021-01-01) Külçe T.; Ateş S.; Olgun Ç.
Using plastic wastes in the forest product industry as an additive material is an alternative solution method for decreasing environmental pollution. For this purpose, in this study; different types of plastic wastes, polyethylene terephthalate (PET), polypropylene (PP), and polystyrene (PS), which have various characteristics and considerable potential as a reinforcing material for wood fibers, were added to the HDF boards on different mixture ratios (25/75, 50/50, 75/25) with already prepared commercial fibers. The changes on some board properties, like density, water absorption, thickness swelling, modulus of elasticity (MOE), bending strength (MOR), and internal bond strength of the produced high-density fiberboards (HDF) was determined. As a result, it was determined that water absorption and thickness swelling ratios of plastic waste added boards were lower than the control samples. Moreover, the mechanical properties of plastic waste used groups (except PET groups) were as nearly as control samples. According to the results, it is possible to easily say that, the PP and PS wastes can be evaluated in the reinforced HDF production process with different mixture ratios for different usage areas.
Influence of cooking variables of Crimean Pine (pinus nigra arnold SBSP. pallassiana) kraft pulp on the resulting paper Sheets
(2008-04-28) Ateş S.; Kirci H.; Tutus A.
A central composite factorial design was used to examine the influence of independent variables of kraft pulping of Crimean Pine wood chips at 50 Schopper-Riegler (oSR) level. Second order polynomial regression equations related each dependent variable to the different independent variables were obtained that reproduced the experimental results for the PFI beating revolutions, breaking length, burst index, tear index, stretch and brightness at 50 oSR obtained at sulphidity, H-factor and active alkali rates over the ranges 15-45%, 800-2400 and 14-22% respectively, with average errors less than %20. To minimize environmental effects of sulphide and acceptable levels of the properties of the paper sheets, low sulphidity rate, high H-factor and medium alkali concentration can be used.
Influence of pulping conditions on the properties of anatolian black pine (pinus nigra arnold ssp. Pallassiana) kraft pulps
(2007-01-01) Ateş S.; Kirci H.
Anatolian Black Pine wood chips were pulped using kraft method in laboratory scale batch digester. A series of experimental kraft pulping was carried out according to Central Composite Design (CCD) to investigate the pulping process and to study the effect of its variables (active alkali rate, sulphidity rate and Vroom's H-factor combining temperature and time) on pulp quality and yield. Second order polynomial regression equations using three independent process variables, were found to be approprite for describing kraft pulping of Anatolian Black Pine wood fibers. The derived equations were able to predict the kappa number, viscosity, yield, holocellulose and α-cellulose content of the pulp with adjusted R2 values of 96.1%, 96.8%, 86.3%, 62.5%, 96.1% and 92.2% respectively. H-factor level and the active alkali charge are the most strongly influcing all the dependent variables. In order to obtain acceptable levels of the pulp properties, high sulphidity rate (45%), medium H-factor (1600) and medium alkali concentration (18%) can be used in kraft pulping of Anatolian Black Pine woods. © 2007 Taylor and Francis Group, LLC.