LEE- Yenilikçi Teknik Tekstiller Lisansüstü Programı

Bu topluluk için Kalıcı Uri

http://hdl.handle.net/11527/19497

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Development of X-ray shielding textile materials with micro and nano sized particles

(Graduate School, 2022) Koyuncu, Bilge ; Candan, Cevza ; Aral, Nebahat ; 732683 ; Innovative Technical Textiles Programme

In many fields of work, including medical diagnosis and therapy, nuclear power plants and space exploration, ionizing radiation (e.g X-ray) is found. These radiation source create serious risks to human health, including mutagenic and carcinogenetic effects on bodily-organs. Therefore, it is important to limit the amount of radiation that professionals who operate in the radiation areas are exposed to. Beer-Lambert equation states that the atomic number, density and thickness of X-ray absorbing materials strongly impact X-ray attenuation performance. Lead (Pb), bismuth (Bi), tungsten (W) and barium (Ba) are common examples of the types of high- atomic number metal compounds utilized to provide efficient shielding fillers in composites with types of polymers. But lead's (Pb) toxicity and density means that it can not be used without precautions as a shielding material. High atomic number, lightweight and non-Pb radiation shielding apparel has become the focus on recent research. Accordingly, this study was conducted in order to develop lightweight, environmentally friendly, textile-based materials which has effective radiation protection using conventional textile coating technology. For this purpose, in preliminary work a coating mixture was prepared utilizing micro copper particles and water-based polymers. In addition to these, micro and nano bismuth oxide powders were employed in preparation of a coating mixture with the help of water-based polymers for this purpose. For advanced characterizing of the coated textile surfaces developed, Fourier Transform Infrared-Attenuated Total Reflectance (FTIR) and Scanning Electron Microscopy (SEM), and Energy Dispersive Spectroscopy (EDS) techniques were used. The radiation attenuation performance of the samples was, on the other hand, measured in accordance to Narrow Beam geometry described in the standard TS EN 61331-1:2014 at Nuclear Energy Research Institute, Turkish Energy, Nuclear and Mineral Research Agency (TENMAK- NÜKEN). The findings of the study have shown that it is possible to produce textile based shielding materials offering lead-equivalent protection without using any lead. Furthermore, it has been shown that the samples with nano powder doping had a greater radiation attenuation rate than those with the micro powder doping, while having almost identical volumetric ratios of powder and coating thicknesses. When comparing the samples with a volumetric ratio of 60%, the 3 plied composite textile based materials containing nano bismuth oxide powder with a thickness of 0.9225 mm provide 83% attenuation at 40 kV whereas the same material present 71.3 % protection at 60 kV. When it comes to the measurement results of the micro bismuth oxide powder with the same values however show 60.2% attenuation at 60 kV. In the study, it was demonstrated that nano-sized powders had a more uniform dispersion in the materials developed than the micro-sized powder particles. The results have also suggested that the layered textile based composite material may attain a sufficient level of lead equivalent. Also, it was found that the attenuation ratio of such materials decreases as the X-ray energy increases. Moreover, by increasing the thickness of the materials the X-ray shielding levels can be increased by 95% and over. In conclusion, it has been shown that lead-free, nature-friendly textile based materials which contain nano and micro powder for use in the field of medical industry can have sufficient lead equivalent protection against X-rays by using traditional textile production methods.
Development and characterization of nanofibrous structures for atopic dermatitis treatment

(Graduate School, 2023) Avcı Pala, Nursema ; Nergis, Banu ; Yılmaz Aral, Nebahat ; 777912 ; Innovative Technical Textiles Programme

Atopic dermatitis (AD) is a chronic, itchy, and inflammatory skin disease that causes dry skin, rashes, and inflammation. Since AD has no definitive treatment so far, moisturizers and softening creams are used to control the disease, whose severity changes periodically; Topical or oral anti-inflammatory drugs and systemic corticosteroids are applied to control exacerbations and to minimize the risk of infection by relieving itching. However, since long-term use of synthetic drugs causes many side effects, it is not recommended for young children and infants, who make up the majority of people suffering from this disease. For this reason, various complementary treatments such as hydrogels, wet dressings or natural oil-added wound dressings have been developed as an alternative to drug therapy. Wound dressings are structures that protect the wounds against various bacteria and infections, support cell proliferation in the injured area, provide the necessary oxygen circulation for the skin, and at the same time maintain the moisture balance of the wound environment. These structures can be woven fabrics (gauze), hydrogels or nanofiber surfaces. Wound dressings can be made functional by adding therapeutic agents on or inside the structure of dressings. When therapeutic agents are added to the surface of dressings post-production, they cannot be released efficiently. In order to achieve sustained release, additives must be trapped in the fibers by different methods during the fiber production phase. Thus, it is possible to adjust the dosage of therapeutic agents and transfer them to the skin surface in a controlled manner according to the healing process. For this reason, studies on nanofiber wound dressings produced by electrospinning method have increased in recent years. Electrospinning is a widely used fiber spinning method for the preparation of nanofibers, versatile and easily adaptable to different materials. Electrospinning apparatus consists high voltage source, conductive polymer solution, syringe, syringe pump, needle/nozzle and collector plate. While the conductive polymer solution, which is fed from the pump and comes to the syringe tip, is drawn from one pole to the other by the electric field effect between the collector plate and the syringe tip, while the solvent in the polymer is removed just before it reaches the collector, and the polymer solidifies, accumulating on the collector plate in the form of nano or micro-sized fibers, forming a nanofiber surface. In electrospinning; Solution or polymer properties, the distance between the needle tip and the collector (collector plate), the amount of applied voltage, the collector movement or environmental factors such as humidity, pressure and temperature are the parameters that affect the nanofiber structure. There are three different electrospinning methods commonly used for the controlled release properties of electrospinning surfaces. These are blend electrospinning, emulsion electrospinning and coaxial electrospinning. Two methods whose sustained release properties can be compared among these three methods are emulsion and coaxial electrospinning. Because the fibers produced by the blend electrospinning method do not show continuous release by making burst release. In the emulsion electrospinning method, the oil phase and the aqueous phase form an emulsion with the help of surfactant added to the polymer solution, and fibers are produced with a single nozzle electrospinning mechanism. With this method, it is possible to encapsulate the additives in the fiber and provide continuous release. The fibers produced by the coaxial electrospinning method are in the core-shell structure. Therefore, sustained release for a long time can be achieved. The nozzle used to obtain this structure has two separate needles, one in the center of the other. Essential oils (EOs) are oils extracted from plants that contain a variety of complex chemical compounds. Since prehistoric times, EOs have been widely used for a variety of medicinal purposes, including antibacterial, antiviral, insecticidal, and analgesic and anti-inflammatory. Because many EOs are volatile by nature, encapsulating oils into the fiber is a cost-effective way to protect them from evaporation and oxidation while also controlling their release. Thyme oil (TEO) used in this study shows high antibacterial activity thanks to components such as thymol and carvacol. Since S.aureus colonization accumulating on the skin surface in AD disease causes exacerbation of the disease, the production of nanofibers containing TEO has been considered as a solution to this problem. On the other hand, Hypericum Perforatum oil (HPO), which has been approved by the literature to contribute to wound healing by supporting cell proliferation thanks to its components such as hypericisin and hyperforin, was chosen as another nanofiber additive. Finally, nanofibers were produced with Borage oil (BO) with the highest Gamma Linolenic acid (GLA) content, which is one of the essential fatty acids that cannot be synthesized in the bodies of patients with AD due to the deficiency of the δ-6-desaturase enzyme. GLA is an important component in AD patients in terms of preventing water loss in the skin and protecting the barrier functions of the skin. In addition to additives, it is also important to use biocompatible and biodegradable polymers in nanofiber production due to their low toxicity and mimicry of the skin's extracellular matrix (ECM). Examples of these polymers are polyvinylalcohol (PVA), polycaprolactone (PCL), polyvinylprolidone (PVP) used in the thesis. In this study, it was aimed to obtain essential oil loaded (hypericum perforatum oil, thyme oil and borage oil) nanofiber structures using emulsion and coaxial electrospinning methods using PVA, PCL and PVP polymers. The effects of the variables on nanofiber structures were evaluated by changing parameters such as polymer type, polymer concentration, essential oil type, essential oil ratio, surfactant type and surfactant ratio. In addition to the production and characterization tests of nanofibrous structures, the antibacterial properties of TEO-containing samples were investigated. Firstly, nanofibers were produced by emulsion electrospinning method using hydrophilic PVA polymer and HPO. The effects of increasing amounts of surfactant used for emulsion formation in the prepared solutions on fiber morphology were observed. Then, emulsion nanofibers were produced with hydrophilic polymers PVP and hydrophobic PCL polymers separately. This time, the amount of surfactant was kept constant and the effects of the increased amount of oil on the fiber structure were examined. After studies on the effect of oil and surfactant in emulsion electrospinning method, nanofibers were produced from PVP/PCL polymers at different rates for the optimization of coaxial nanofibers. The morphologies of the produced fibers were examined, the hydrophilicity/hydrophobicity test was performed on the surfaces and the effect of polymer ratios on the surface properties was investigated. As a result of the studies, the most suitable polymer ratio was determined for oil loading. Oil-loaded fiber productions were made by adding TEO, BO and TEO:BO (1:1 v/v mixture) to the PVP polymer, which will form the core structure of the fiber in coaxial fibers. The results of SEM images, fiber diameter distributions, FTIR and antibacterial activity tests of the produced samples were analyzed and interpreted. Finally, oil-loaded nanofibers with a hydrophobic PCL polymer core/shell structure were produced. While the shell polymer solution was kept constant at 10% wt PCL, the core polymer solution was prepared at 10% wt PCL and 8% wt PCL. TEO and TEO:BO mixed oils were added to the core solutions as oil additives. The obtained nanofibers were evaluated in terms of fiber morphology and surface hydrophilicity, the connections between the viscosity and conductivity values of the solutions and fiber structures were explained, and suggestions for future studies were presented.
Detection and analysis for microplastics originating from the textile industry

(Graduate School, 2023-01-17) Akyıldız, Sinem Hazal ; Eniş Yalçın, İpek ; Yalçın, Bahattin ; 503191850 ; Innovative Technical Textiles

The textile industry is one of the most polluting industries in the world in many areas: harmful chemicals used, high energy and water consumption, harmful gases released into the environment, chemicals discharged into water, and textile wastes buried or incinerated in the ground. Nowadays, we are faced with a new problem whose awareness is increasing, and that is microplastics. Microplastic pollution emerges as a critical environmental problem resulting from the decomposition of large-sized plastics into smaller micro- or nano-plastics in nature. There are many sectors that cause the formation of microplastics. At the beginning of these, the textile sector took its place. Petroleum-derived textiles are generally produced from various raw materials such as polyester, polyamide and acrylic, and synthetic fabrics produced from these fibers generate a large amount of microfiber wastes from their production to consumption and even disposal processes. While the wet and dry processes that synthetic fabrics are exposed to in their production processes cause microfibers to mix with air and water, it is a known fact that these fabrics emit a substantial number of microfibers both during the washing process and during daily use from the day they meet the consumer. Each washing of synthetic fabrics in household washing machines causes thousands of microfibers to separate from the fabric. Therefore, the textile industry is one of the leading sectors that cause significant microplastic pollution. These microfibers can then be ingested by marine life and enter the food chain, posing a potential risk to human health. Microplastics are found not only in marine life, but also in areas such as air and soil. For this reason, it has become an inevitable problem in our lives. In fact, in some studies carried out beyond this, it has even been found in caves, underground waters and drinking water. Microplastics, which are found in most animals and people around the world, are known to be bad for health, but how much their effects will get worse over time is still unknown, which is a cause for concern. Studies have proven that microplastics can be reached even in human blood. Therefore, the determination and analysis of microplastics, the number of which is increasing exponentially every day, is very important. There are several ways in which the textile industry can contribute to microplastic pollution: Fabric production: The production of synthetic fabrics generates microfibers as a byproduct. These fibers can be released into the air or water during the manufacturing process. Fabric use: Synthetic fabrics can shed microfibers when they are laundered or worn. These fibers can enter the environment through wastewater treatment plants. Fabric disposal: Synthetic fabrics do not break down easily in the environment and can contribute to plastic pollution when they are discarded. This thesis focuses on the detection and analysis processes of microplastics originating from the textile industry, for which there are not enough studies yet. Within the scope of the studies, the most effective pretreatment and separation techniques were determined for the removal of microplastics from textile wastewater. In addition, the amount of microplastics generated by textile fabrics with various structural components and different raw materials during washing were investigated, and the parameters affecting the process were determined. Experimental studies carried out within the scope of the thesis are examined in three separate sections. We must first correctly identify the problem in order to produce a solution. There is not yet a clear standard method for the detection, separation, and analysis of the microplastic problem we are facing. Based on this, part of this study focused on the necessary steps for the most effective detection, separation and analysis of microplastics originating from the textile industry. The process of removing organic substances by treating artificially obtained textile wastewater with various chemicals constitutes the first experimental stage of the thesis. In this context, various synthetic fibers (acrylic, polyester and polyamide) were dyed at varying temperatures and times, under suitable conditions, and an artificial wastewater was obtained from the dyeing water enriched with extra microfibers. Fenton reagent, H2O2, HCl, KOH and NaOH chemicals were used in various ratios to remove the organic substances in its content. The results obtained at this stage showed that the least damaging pretreatment to the fibers was 15% H2O2. When the results of these chemicals treated at two different temperatures and times are evaluated, it is concluded that the treatment period of 5 days at room temperature is more efficient in terms of energy consumption. After the most effective pretreatment selected in the first stage, second stage starts. This time the processes of removal and analysis of microfibers in industrial textile wastewater were realized. In this context, industrial wastewater was supplied from Kadifeteks company. Centrifugation, density separation and filtration methods were tried to separate microfibers from the pre-treated industrial textile wastewater and as a result, filtration method was chosen as the most suitable separation method. Production, use, and disposal are among the reasons for the release of microplastics originating from the textile industry into the environment. While the first two parts of the study focus on the production phase, the third part focuses on the use phase. Hence in the last stage of the thesis, the evaluation process has been started for the consumption process, which is at least as effective as the production process. In this context, first of all, the structural properties of the fabrics were taken into account, and it was examined how the properties such as the fabric type, thickness, basis weight and raw material type of the fabrics could be effective for microfiber release. For these studies, polyamide, polyester, recycled polyester, acrylic and polypropylene fabrics were provided, and their effects on microfiber release were evaluated by examining the properties of the fabrics. In this context, the washing processes of synthetic fabrics were imitated within the framework of laboratory facilities and the effect of the pre-wash program used in washing was examined. The main purpose of this last stage is to achieve results that can raise awareness among consumers. Since the prewash program is a selectable program in washing machines, determining the amount of microfiber released by the effect of this program is important in terms of consumer awareness. When the results obtained were evaluated, it was found that woven fabrics cause more microfiber release than knitted fabrics, utilizing recycled polyester rather than virgin polyester increases microfiber release, and pre-washing process causes microfiber release at least as much as the washing-rinsing process. One of the aims of this part of the study was to see how much fiber is spread when we wash the synthetic clothes we wear, thus increasing the awareness of consumers and enabling them to change their preferences. Moreover, no study has ever been done before, and the uniqueness of this study was the observation of how much we actually increased the microfiber release into the environment when we chose to pre-wash. Not only do our purchasing habits need to change, but so do our usage habits. Accordingly, it has been found that washing our laundry without a prewash and with a short program will reduce the release of microfibers. When all the results of the experimental processes within the scope of the thesis are evaluated, it can be said that important steps have been taken in terms of the determination, separation and analysis of microfibers in textile wastewater.
Development of a gas sensing nanofibrous membrane for asthma detection

(Graduate School, 2024-01-09) Hakgör, Ari ; Eryürük, Selin Hanife ; 503201820 ; Innovative Technical Textiles

In this study, a membrane consisting of zinc oxide nanofibers was formed through electrospinning process in order to be used in gas sensing tests for determining the nitrogen oxides (NOx) gases which exist in the exhaled breath of asthma patients more than those of healthy people. Various attempts had been made to get the best result concerning the ease and continuity of the process at production step. Polyvinyl alcohol (PVA) and Zinc acetate dihydrate (Zn(OAc)2·2H2O) were used as precursor substances for membrane formation. Zinc oxide (ZnO) nanofibers-based membranes were obtained after calcination process. In order to determine the best polymer concentration for electrospinning solutions; PVA solutions at concentrations ranging from 7% to 20% (w/v) were prepared, firstly. According to the rheological study results, 15% PVA (w/v) was found the most proper concentration among them in terms of the level of the polymer chain entanglement that provided sufficient viscosity. Four different mass ratio of Zn(OAc)2·2H2O with respect to the polymer concentration; 1:0.5, 1:1, 1:1.5 and 1:2 were introduced to the solutions for finding the most proper electrospinnable solution for ZnO formation. Some physicochemical and rheological analyzes such as pH, conductivity, viscosity and surface tension measurements were carried out in order to evaluate the electrospinnability of each solution and also to suggest the possible reactions of intermediate products formed in aqueous medium. The conductivity, surface tension and viscosity values of the solutions increased with an increase in Zn(OAc)2·2H2O concentration; however, a decrease in pH was observed. This was probably due to the consumption of the hydroxide ions in PVA / Zn(OAc)2·2H2O solutions, in order to form an aqueous intermediate product, zinc hydroxide Zn(OH)2. Moreover, thermogravimetric analysis (TGA) was carried out for defining suitable thermal parameters for calcination process. The scanning electron microscopy (SEM) analysis was employed to the membranes prepared both before and after calcination processes. As far as the all analyzes and measurements were concerned, it was estimated that the formation of ZnO overlapped with the late decomposition of PVA during the thermal process, around 600°C. The formation of ZnO proceeded through the transformation of Zn(OH)2 by loss of water molecule. Among the prepared samples, 15% PVA solution with equivalent amount of Zn(OAc)2·2H2O showed the best performance considering the fineness of nanofibers and the amount of products or reactants produced or used; however, the continuity and stability at the region of taylor cone and jet were not found satisfactory enough. That is the reason why, various attempts were applied to all samples in order to get more optimized electrospinning process. In the last part of the study, the solutions were re-prepared and investigated in acidic and basic medium, in water:ethanol binary solvent system and in the presence of surfactant. After conducting all necessary analyses, it was concluded that adding 1% (w/v) non-ionic surfactant to the solution of 15% PVA: 15% Zn(OAc)2·2H2O provided more stable and continuous electrospinnability predominantly thanks to the decrease in surface tension of the solution.
Investigation of physical performance of denim fabrics washed with sustainable foam washing

(Graduate School, 2024-01-16) Yılmaz, Hazal ; Karakaş, Hale ; 503201831 ; Innovative Technical Textiles

Denim fabrics, which have a great importance in the textile industry, are always developing from past to present. Denim fabrics, which have been used for a long time and have not lost their popularity, have a very wide usage area today. Even if the perception of fashion changes, denim products have always maintained their place in the industry. Although denim fabrics are most frequently used as trousers in the textile industry, they are also widely used in products such as dresses, skirts, bags, home accessories and shoes. In addition to its product diversity, it is highly preferred in the textile industry due to its durability. The most important stage that makes denim fabrics visually appealing to the fashion industry is the washing process. The final appearance of the denim is achieved by giving the desired effects to the product with the washing processes carried out at the final stage. With different washing methods, denim is given many visual effects such as worn, vintage, faded, shiny etc. A lot of water and chemicals are being used during denim washing processes, and this problem has been a subject of many researches for a long time. Re-using the waste obtained from denim washing causes another energy loss. This problem exists not only in denim manufacturing but also in many areas of the textile industry. When the damage caused to the environment by the textile and apparel clothing industry is examined, many concepts such as sustainability, ecological production and waste-free production have come to the fore. For this reason, many companies, factories and organizations are looking for new researches and initiatives to do their production using less water, chemicals and energy. Denim production is one of the process that consume much water and chemicals in the textile industry. Many denim manufacturers and brands are still looking for new solutions to reduce this damage. Today, alternative and sustainable searches still continue. Stone washing is one of the most common washing methods used in the denim industry for many years. Stone washing is being processed in industrial washing machines by using pumice stones. Washing times vary depending on the effect desired to be achieved. With the rotation inside the industrial washing machines, dyestuff on the garment wears off due to the friction between garment and stones and the desired effect is achieved. During this process, a lot of water is being consumed and the pumice stone damages the garment when friction is high. Therefore, after the washing process is completed, pumice stones must be carefully removed from the garment and should be cleaned. The process of removing pumice stone requires another rinsing process, and pumice stone that is not completely cleaned from the garment can be harmful for human health and the product. In addition, pumice stone becomes unusable by shrinking or decomposing after a few washing processes. Unusable stones causes waste problem, and also recycling or stock processes of these left stones causes another workload and energy loss. For this reason, washing processes that can be an alternative to stone washing have been the subject of many searches since the past. There are methods that have been developed and are still being developed by many researchers to reduce the use of water and chemicals or to prevent the use of pumice stones. The aim of this thesis, in cooperation with Ereks Blue Matters Factory, is to offer a new sustainable method in which less water and chemicals are being used and the use of pumice stones is eliminated, as an alternative to stone washing. For this purpose, a new technology, the foam washing method, was investigated and washing experiments were carried out. Washing trials were carried out to obtain the effects given by friction of the pumice stone on the fabric in industrial washing machines, by spraying foam on the same washing machines. In the study, firstly stone washing and foam washing recipes and washing process stages were compared. Secondly, the physical properties of the fabrics obtained from stone washing and foam washing were analyzed and compared with each other. For this study, 7 different denim fabrics with different compositions and weights, which are most commonly used in production at the Ereks Blue Matters factory, were selected. Two of the same fabrics were produced, processed as same until washing stage. For the washing process, one fabric was washed with stone while the other fabric was washed with foam. Washing trials were carried out separately for 30, 60 and 90 minutes for each fabric type. As a result of the washing trials, a total of 42 washed denim fabric samples were obtained, 21 stone washed and 21 foam washed. In order to compare the physical performances of obtained samples, color fastness to domestic and commercial washing, color fastness to rubbing, abrasion resistance according to the Martindale method, color analysis with spectrophotometer, stiffness of fabric by the circular bend procedure, tear and tensile strength tests were carried out in Istanbul Technical University Textile and Apparel Quality Control Laboratory. With James H. Heal Titan machine, tear strength test according to TS EN ISO 13937-2 and tensile strength test according to TS EN ISO 13934-2 were evaluated. Abrasion test according to Martindale method was evaluated in James Heal Martindale & Pilling Tester according to TS EN ISO 12947-2. Color fastness to rubbing test was evaluated in SDL Atlas Crockmeter according to TS EN ISO 105-X12. Color fastness to washing test was evaluated in Linitest machine according to TS EN ISO 105-C06, stiffness of fabric by the circular bend procedure was evaluated in A&T Machine according to ASTM D4032 and color analysis was evaluated with Datacolor 650ᵀᴹ spectrophotometer. Test results were compared according to washing durations 30, 60 and 90 minutes for foam and stone washed fabrics. When the test results were evaluated, it was seen that less water was used during the foam washing process compared to stone washing. When the test results were compared, the tear strength test results were higher in all fabrics washed with foam for both weft and warp yarns. Tensile strength test results varied and no generalizable result could be determined for foam or stone washed fabrics. When the wet/dry rubbing fastness and washing fastness test results were evaluated, it was observed that the rubbing and washing fastness values of foam washed fabrics were generally better than stone washed fabrics. As a result of the evaluation, it was determined that the rubbing and washing fastness values of foam washed fabrics were better or the same as stone washed fabrics. After abrasion resistance test according to the Martindale method, no yarn breakage was observed for foam 40,000 cycles. For all fabrics, weight loss was observed as the rpm increased, but a regular rate was not detected in decreasing weights. In most of the tested fabrics, it was seen that the weight loss after 15,000 rpm was less for foam washed fabrics than for stone washed. It was determined that only for 4 types of foam washed fabrics, the weight loss was higher than stone washed, but this difference was less than 3%. When all test results were evaluated, it was determined that the physical properties of denim fabrics washed with the foam washing method were preserved or better. Therefore, it has been proven that the new method can be used in the industry. Although the test results of foam washed fabrics are not significantly superior to stone washed ones, the difference in the ratio of water and chemicals used is quite high. Also, the use of pumice stones is eliminated with the foam washing process, and energy consumption in the process of removing pumice stones or stock waste will be prevented. When these results were evaluated, it was determined that the foam washing method can be used as a sustainable alternative to the stone washing method. Thus, an environmentally friendly method has been developed which can be accepted in the textile industry.
Development and application of reactive dye microcapsules for cotton fabric dyeing

(Graduate School, 2024-06-25) Kalkan, İsmet Ege ; Şahin, Umut Kıvanç ; 503211864 ; Innovative Technical Textiles

Hızla artan dünya nüfusuyla birlikte tüketici sayısı da artmaktadır. Tekstil sektörü dikkate alındığında diğer doğal liflere göre en yaygın kullanılan doğal elyaf pamuktur. Sunulan çalışmada, havlı kumaşların renklendirilmesinde kullanılan reaktif boyarmaddelerin mikrokapsül teknolojisi ile kapsüllenerek boyama banyolarında kullanılması, bu sayede de çevre dostu bir proses elde edilmesi amaçlanmaktadır. Tekstil sektöründe pamuk boyamada kullanılan reaktif boyarmaddeler genellikle üçlü karışımlar halinde uygulanmaktadır. Bu boyarmaddeler çoğunlukla otomasyona uygun olmayan toz halinde HT makinalarına beslenmektedirler. Reaktif boyamada uygulanan boyama reçetesinde kullanılan boyarmaddelerin %100'ü pamuğa bağlanamaz. Maksimum %70'i pamuğa bağlanır. Boyarmaddelerin geri kalan %30'u su fazına geçer. Bu su fazına geçen boyarmaddeler suda çözünmeyen ve arıtılması zor olan maddeler içermektedir. Aynı zamanda çevresel atık yükünü de artırmaktadır. Çalışma kapsamında reaktif boyaların mikrokapsül teknolojisi ile kapsüllenmesiyle hem kullanılan boya miktarının hem de çevresel atık yükünün azaltılması amaçlanmaktadır. Bu sayede boya tasarrufu sağlanacaktır. Tekstil endüstrisi, çevresel açıdan sürdürülebilir ve enerji açısından verimli yeni üretim yöntemleri geliştirmekte ve yenilemektedir. Bu yeni yöntemler sektörün çevresel etkisini azaltırken pazardaki rekabet gücünü de artıracaktır. Tekstil sektörü her ne kadar geleneksel yöntemlerden vazgeçmek istemese de günümüz teknolojisinde kullanıcı taleplerine cevap vermek ve pazar payının arttırılması önemlidir. Değişen dünyada, projenin başlangıcından itibaren ortaya çıkacak yeni ürün, sadece yeni ürünleri esas almak değil, aynı zamanda temiz enerji, temiz üretim, sürdürülebilir üretim, asgari düzeyde anlayışa sahip olmak açısından da tamamen bu kavramlara dayalı olacaktır. Proje kapsamında detaylı literatür araştırması yapılmıştır. Günümüzde pigment boyarmaddelerinin kapsüllenmesine yönelik çalışmalar oldukça nadirdir. Proje kapsamında gerçekleştirilecek çalışmanın ilklerden biri olması hedefleniyor. Projenin sonucu daha sürdürülebilir bir üretim yöntemi yani konvansiyonel boyama sırasında karşılaşılan enerji, su ve zaman kaybı nedenlerinden uzaklaşarak daha hedefe yönelik bir üretim elde edilmesidir. Projenin beklenen sonucu Avrupa ve ABD test standartlarına uygun, çevreye ve insan sağlığına zarar vermeyen yenilikçi bir üründür.
Fabrication, characterization and drug release behaviors of electrospun PEtOx/Flubendazole nanofibrous webs

(Graduate School, 2024-07-11) Sürücü, Elif ; Eniş, İpek Yalçın ; 503201827 ; Innovative Technical Textiles

Filarial infections in humans result in deteriorating health conditions for over a hundred million people, particularly in some low-income countries in Africa and Asia, notably sub-Saharan Africa. They lead to diseases like lymphatic filariasis and onchocerciasis, with 120 million people currently afflicted by this disease. Flubendazole is the most appealing benzimidazole drug for the treatment of filarial parasites. It is also licensed and marketed in Europe as Fluvermal to treat intestinal nematodes in humans. However, it is a benzimidazole methylcarbamate anthelmintic with poor water solubility and is included in the Biopharmaceutics Classification System (BCS) class IV compound. For this reason, it has poor solubility in the aqueous systems formed in the gastrointestinal tract, shows poor absorption in the blood circulation and therefore its bioavailability is extremely low. These drawbacks can be deal with by the use of amorphous solid dispersions (ASD), which is a promising approach to improve the oral bioavailability of poor water-soluble drugs. ASDs prepared with water-soluble polymeric carriers are used to enhance the dissolving ratio and potentially bioavailability of such hydrophobic drugs. Electrospun nanofiber-containing ASDs possess exceptional physical stability due to the molecular distribution of the drug within the fibers, and the polymer chains provide a steric barrier against the recrystallization of the drug. Further, it improves drug dissolving rates in aqueous conditions due of their three-dimensional construction and high interconnected porosities with configurable pore sizes, allowing for effective surface functionalization. The solvent used to prepare polymeric solutions has a crucial impact on achieving extremely high drug loading and electrospinnability. Over the past decades, poly(2-ethyl-2-oxazoline) (PEtOx) has found application as a polymer in biomedical and pharmaceutical fields, particularly for delivering hydrophobic drugs, proteins, and nucleic acids. It has exceptional biocompatibility, lack of toxicity and anti-fouling properties. Furthermore, various researches on PEtOx have stated that PEtOx has great stability in body, and no tissue destruction, being the polymer safe for use for body. In this thesis, ASDs were developed and fabricated by loading PEtOx with 40%, 45%, 50%, or 55% wt. flubendazole using the electrospinning method. The resulting nanofiber membranes were examined in detail in three different surface forms. Physical, morphological, and thermal characterizations of the surfaces were conducted, and the effects of using PEtOx, flubendazole ratio, and surface form on in-vitro drug release behaviors were investigated. Scanning Electron Microscope (SEM) analysis showed that homogeneous and continuous fibers were obtained on the membrane surfaces regardless of the flubendazole ratio. Crimped fibers were observed in the samples with the cut surface form, while flattened fibers were seen in the ground samples. The fiber diameter measurements indicated that the fiber diameter tended to increase with a higher flubendazole ratio, and although no difference was observed in the cut samples, flattening was noted in the grinded samples. When examining the results of Differential Scanning Calorimetry (DSC) analysis, it was found that glass transition temperature (Tg) values were between the Tg of pure flubendazole and PEtOx. This indicates that both components are blended at a molecular level. On the other side, it was found that Tg values increased with the flubendazole ratio, regardless of the surface form. The surface form did not show a significant affect on Tg values. Evaluating the drug release profiles revealed that the release rate was decreased by the increasing flubendazole ratio, whereas the fastest release obtained in the cut surface form. Additionally, while crystalline flubendazole achieved a release rate of 2.12 mg/mL at the 60-minute mark, the ASDs produced with different flubendazole concentrations exhibited drug release in the range of 7.46-14.48 mg/mL which showed that PEtOx loaded with flubendazole exhibited a higher release amount. In this context, it is thought that ASD systems developed within this thesis represent an innovative design with promising potential for the release of poorly soluble drug.
Development and characterization of surgical locally oxidised regenerated cellulose hemostats

(Graduate School, 2024-07-25) Şeremet, Beyza ; Göcek, İkilem ; 503201824 ; Innovative Technical Textiles

Blood is not only a special fluid that transports gases and nutrients but is also responsible for immune control and hemostatic response. Generally, mild bleeding can be stopped by congenital clotting. However, excessive blood loss can cause morbidity (illness) and even mortality (death). Therefore, when haemorrhage occurs, there is a critical time window in which effective treatment must be given to save lives. Uncontrolled excessive bleeding is a life-threatening emergency scenario that significantly impairs patients' survival within the first 48 hours and causes millions of deaths worldwide each year. Large-scale bleeding in battlefields, traffic accidents and during surgical operations can cause high blood loss, which adversely affects physiological processes in the body. With excessive blood loss, there is a decrease in the amount of blood carrying nutrients and oxygen necessary for the metabolic activities of cells in tissues and organs, and metabolic wastes produced by cells begin to accumulate in the intercellular space. If bleeding cannot be prevented for a long time, the blood necessary for the heart to function itself cannot be supplied and bleeding may result in death. In addition, uncontrolled bleeding in patients with coagulopathy is associated with massive bleeding in emergency situations. Excessive bleeding may disrupt the hemodynamics of patients and may require additional blood transfusion. Prolonged treatment may cost life. Therefore, it is critical to stop bleeding in emergencies, especially in cases of organ trauma. In addition, uncontrolled bleeding is not only a life-threatening situation for patients, but also a great financial burden for health services. In this context, hemostatic agents are vital for the rapid prevention of bleeding. Hemostatic materials are generally produced from natural materials such as chitosan, cellulose, starch. Existing hemostatic agents have disadvantages such as acidity, surrounding cell damage, acute/chronic inflammation, thrombogenic complications, non-biodegradability, limited application methods, short shelf life and high cost and impose a serious cost on health expenditures. In this respect, it is important to develop materials with low cost and hemostatic properties to stop bleeding at the time of injury. The main aim of this project is to produce an absorbable hemostatic agent from sustainable natural origin cellulosic fibres obtained from cellulose wastes and to quickly stop and prevent bleeding in tissues. These hemostatic agents produced from polysaccharides or other biopolymers are expected to have properties such as biodegradability, biocompatibility and non-exothermic reaction, and these issues have become the focus in the development of new generation hemostatic materials. In this study, it is planned to produce a non-woven, absorbable hemostatic material that accelerates plasmination for the first time by using TENCEL fibre, which is produced from polysaccharide type materials, sustainable regenerated cellulose obtained from cellulose wastes, provides more hygienic properties by creating an environment less favourable to bacterial growth and has the potential to reduce the risk of irritation and negative effects on the body by providing a smoother surface and softness. It is aimed to use TENCEL fibre as the main material in the production of cellulosic hemostatic agent and to develop surgical local hemostat by oxidation of the felt to be obtained. Thus, it is aimed to evaluate innovative natural origin sustainable fibres in the production of medical textile products and to transform them into value added products. As a start, Tencel fibre supplied by Göl Iplik, one of our project sponsors, was purchased in fibre form and delivered to Karınca Filter facilities, also one of our project supporters. Our Tencel fibre was taken to the Dilo machine in the facility where fiber preparation, carding, cross-laying, lap drawing and needling processes were carried out respectively. Firstly, 16 plies were tried in cross-laying, but since the thickness of the product was too high, the number of plies was also tried as 12 and 8. As the tencel fibre gains volume after passing through the carding machine, the product was also evaluated by needling at the same time. Two different drums of the needling section were evaluated and our 8-layer product was needled as 49K and 16K respectively and formed as 2 different samples. Finally, 4 types of samples were chosen for the subsequent studies: 12 layers un-needled, 8 layers un-needled, 8 layers 49K needled and 8 layers 16K needled. Afterwards, by comparing the samples chosen with their equivalents in the market, it was decided that the 8 ply 16K needled sample was the most suitable one with the properties required. 8 ply 16K needled sample, which is accepted as the optimum sample, has been oxidised. The oxidation process was carried out in a closed system in a stainless metal boiler in Yucel Medical facility. In the closed boiler, 250 grams of nitrogen dioxide (NOx) gas was given for 3 kg of nonwoven product and the trapped product was kept at a temperature of 20-25 C for 24 hours. Afterwards, it is removed from the boiler and placed in a container containing approximately 10 litres of ethyl alcohol by an operator using a mask as soon as it is removed. It is kept in the container full of ethyl alcohol for 30 minutes. Afterwards, the pH value is measured, if it is not suitable, ethyl alcohol washing is continued again. After washing 4 times with ethyl alcohol, the desired pH value is reached. The pH value is targeted between 2,8 and 4. The reason for this is the antibacterial effect of the product between these standards. Then it is left to dry in a clean environment in a laminal cabinet. It is dried and kept for about 12 hours. After nonwoven products of suitable texture formed by using Tencel fibre were oxidised under suitable ambient conditions, carboxyl ratios, optimum pH and solubility were achieved. Moreover, loss on drying test, nitrogen content, formaldeyhyde test is performed, and the results are in the standards according to USP28 (United States Pharmacopeia) Pharmacopoeia standard. Carboxyl test was applied on the dried product to determine carboxyl ratios. The purpose of this is to see whether the product complies with the USP28 (United States Pharmacopeia) Pharmacopoeia standard. The appropriate carboxyl amount indicates that the product can be absorbed in the body. Since pH is a crucial factor in determining a material's biological compatibility and functioning, pH test was applied. The degree of oxidation and the presence of acidic groups in oxidized regenerated cellulose might influence how the material dissolves or is suspended in water. Solubility testing of oxidised regenerated cellulose (ORC) is necessary to evaluate its performance in medical applications. Drying loss test was applied to the newly produced product and the product on the market. Specific weights of materials taken separately from both samples will be dried at specified temperatures for 2 hours. After drying, the weight of the materials will be measured again. Nitrogen content analysis on oxidised regenerated cellulose is a fundamental analytical technique that supports quality assurance, regulatory compliance and research efforts related to this important biomaterial. That is why we did the nitrogen content test. Formaldehyde testing on oxidised regenerated cellulose is essential to verify compliance with safety regulations, ensure patient safety and maintain the quality and integrity of the material for medical applications. For this reason, we performed the formaldehyde test. In the method used in the production of the hemostatic agent developed within the scope of the project, the information obtained from the literature was combined with the research experience of the project team and the process parameters were determined and optimised. In addition, tests of the produced hemostatic material and a commercial material were carried out in accredited laboratories and the potential for commercialisation was evaluated by comparing their performances.

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