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Manufacturing and heat transfer analysis of nano-micro fiber compositesAşcioğlu, Birgül, Adanur, Sabit, January 2005 (has links) (PDF)
Dissertation (Ph.D.)--Auburn University, 2005. / Abstract. Vita. Includes bibliographic references.
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Obtenção e caracterização de mantas fibrosas de poli(fluoreto de vinilideno) (PVDF) com poli(o-metoxianilina) (POMA) pela técnica de "Solution Blow Spinning" /Oliveira, Danilo de Freitas. January 2016 (has links)
Orientador: José Antonio Malmonge / Resumo: Micro e nanofibras poliméricas têm despertado grande interesse de pesquisadores devido as suas potencialidades em diversas aplicações, atribuídas principalmente à grande área superficial destes materiais em associação com as propriedades dos polímeros. Uma das técnicas utilizadas para produção de micro e nanofibras é a solution blow spinning (SBS), ou fiação por sopro em solução. Neste trabalho foram obtidas microfibras de blendas de Poli(fluoreto de Vinilideno) (PVDF) e Poli(o-metoxianilina) (POMA), com a POMA em seu estado dopado e não dopado, pela técnica SBS. Para a dopagem da POMA foi utilizado o ácido p-toluenosulfônico (TSA). Obteve-se mantas com concentrações de PVDF/POMA-TSA de até 85/15 (m/mtotal), e de até 90/10 (m/mtotal) para PVDF/POMA. Foi possível observar a partir das imagens de MEV que os diâmetros médios das fibras diminuíram com o aumento da concentração de POMA, chegando a 0,22 µm para a maior proporção. Essa variação no diâmetro das microfibras é atribuído a variação da viscosidade da solução que diminui com o conteúdo da POMA na blenda. Os difratogramas de raios X indicaram que tanto a fase α quanto a fase β do PVDF foram obtidas no processo de fiação tanto para o PVDF puro bem como para a blendas, mostrando que o conteúdo de POMA na blenda não altera a fase do PVDF. A condutividade elétrica das fibras aumentou significativamente com a porcentagem de POMA (dopada) na blenda, elevando os valores em até 8 ordens de grandeza e atingindo uma condutividade ... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Micro and polymeric nanofiber have arisen great interest of researchers because of their potential in various applications, mainly attributed to the large surface area of these materials in association to the properties of polymers and polymer blends. One of the techniques used for producing micro and nanofibres is the solution blow spinning (SBS). In this study microfibers of poly (vinylidene fluoride) (PVDF) and poly (o-methoxyaniline) (POMA) blends were obtained, with POMA in its doped and undoped state, by SBS technique. For POMA doping it was used p-toluenesulfonic acid (TSA). Mats with PVDF / POMA-TSA concentrations of 85/15 (m /mtotal), and up to 90/10 (m /mtotal) to PVDF / POMA were obtained. It was possible to observe from SEM images that the average fiber diameters decreased with increasing concentration of POMA, reaching 0,22μm at the highest proportion. The X-ray diffractograms showed that both α phase and β phase of PVDF were obtained in the spinning process. Such phases didn’t have their formation affected by the variations on the bend concentration. The electrical conductivity of the fibers increased significantly with the percentage of POMA (doped) in the blend, increasing values up to 108 orders of magnitude and reaching a conductivity of about 10-4 S/cm for the mats of PVDF/POMA on the reason 85/15. Furthermore, the mats of the blend showed good thermal stability up to the temperature of 200 °C. / Mestre
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Fabrication of a tissue- engineered perfusable skin flapWeinreb, Ross H. 17 June 2016 (has links)
To date, the reconstructive approach addressing chronic non-healing wounds, deep tissue damage, and severe wound defects relies upon avascular dermal grafts and autologous flap techniques. Such flaps are limited by donor site availability and morbidity, while current dermal grafts rely upon host cellular invasion for neovascularization and incorporation. These products fail to include an inherent vascular network and the supporting cells necessary to ensure adequate incorporation and graft survival beyond the most optimal wound beds. Herein, we fabricate a pre-vascularized full-thickness cellularized skin equivalent containing a three-dimensional vascularized network of interconnected macro and microchannels lined with vascular cells, within a collagen neodermis populated with fibroblasts, and an epidermis comprised of human keratinocytes capable of providing whole tissue perfusion.
Previously, our lab has employed a sacrificial microfiber technique to develop tissue-engineered scaffolds with an inherent hierarchical network of microvessels, which recapitulates the organization of an arteriole, venule, and capillary bed. Utilizing a type-I collagen hydrogel matrix, vascular cells were seeded within pre-fabricated channels and allowed to proliferate to generate an endothelialized microvasculature. These collagen scaffolds were subsequently anastomosed into rat models to demonstrate the clinical feasibility of such approach. The present study aims to more closely recapitulate the in vivo structure of human skin via the incorporation of vital epidermal and dermal components of native skin into a biocompatible construct containing a complex hierarchical vasculature, which may be anastomosed using standard microsurgical techniques and immediately perfused.
Pluronic F127 was used as the sacrificial material: 1.5 mm diameter “U” shaped macrofibers and 100-500 µm-interwoven microfibers were heat extruded and then embedded within type-I collagen into which Cyan Fluorescent Protein (CFP)-tagged human placental pericytes and human foreskin fibroblasts (HFF1) had been encapsulated. Following pluronic sacrifice, resultant channels were intraluminally seeded with Red Fluorescent Protein (RFP)-tagged human aortic smooth muscle cells, Green Fluorescent Protein (GFP)-tagged human umbilical vein endothelial cells, and topically seeded with human epidermal keratinocytes (HEK). Construct microstructure was analyzed using multiphoton microscopy (MPM) after 7, 14 and 28 days of culture. Additionally, after 14 and 28 days of culture, endothelial cells were extracted from the construct using collagenase digestion and Real Time (RT)-qPCR performed to analyze expression of markers of angiogenesis and maturation of the vascular network.
MPM demonstrated a hierarchical vascular network containing macro and microvessels lined by endothelial and smooth muscle cells, supported by perivascular pericytes, all in appropriate microanatomic arrangement. Neodermal HFF1 proliferated throughout the observation period and the HEK neoepidermis developed into a stratified epidermis along the superior aspect of the construct. Angiogenic sprouting from the nascent vascular network into neovessel like structures was noted. RT- qPCR revealed relative expression of Jagged1, Dll4, Ve-Cadherin, and CD31. We have successfully fabricated a novel tissue-engineered pre-vascularized full thickness skin flap, which recapitulates the inherent hierarchical vasculature found within human skin and is suitable for in vivo perfusion. We provide the platform for an on- demand, geometrically tunable tissue engineered skin equivalent with an anastomosable vascular network. This tissue-engineered skin flap holds the potential to transform reconstructive surgical practice by eliminating the consequences of donor site morbidity, and enabling rationally designed, patient-specific flaps for each unique wound environment and anatomic location. / 2017-06-16T00:00:00Z
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Síťování polysacharidových mikrovláken / Crosslinking of polysaccharide microfibersSvidroňová, Barbora January 2014 (has links)
Všeobecne, cieľom tejto diplomovej práce bola príprava a charakterizácia sieťovaných hyaluronových mikrovláken, ktoré by boli stabilné vo vodnom prostredí s vhodnými mechanickými vlastnosťami. Vlákna pripravené technikou zvlákňovania z roztoku boli sieťované pomocou roztoku so sieťovacím činidlom 1-Ethyl-3-(3-dimethylaminopropyl) carbodiimidom alebo roztoku s dvoma sieťovacími činidlami 1-Ethyl-3-(3-dimethylaminopropyl) carbodiimidom a N-hydroxysuccinimidom, vedúcim k amidácii a tvorbe esterových väzieb. Charakterizácia pripravených vzoriek je hlavným cieľom experimentálnej časti práce. Charakteristiky botnání boli vykonané na určenie stability vláken v troch rôznych roztokoch (s pH 7.4, 3 a 11). Na určenie termickej stability bola využitá termogravimetrická analýza a na stanovenie esterifikácie a amidácie bola použitá infračervená spektroskopia s Fourierovou transformáciou. Mechanické vlastnosti vláken boli študované pomocou testovania závislosti stress-strain. Ďalej boli testované reologické vlastnosti ako aj mikroštruktúra a povrch vláken pomocou skenovacieho elektrónového mikroskopu. Vlákna pred chemickým sieťovaním vykazovali nižšiu stabilitu vo všetkých troch roztokoch, termálna stabilita bola taktiež nižšia ako stabilita zosieťovaných vláken. Pre vlákna chemicky nemodifikované so sieťujúcim činidlom, sa objavil iba jeden typ píku pre esterifikáciu. Infračervené spektrum chemicky zosieťovaných vláken ukázalo prítomnosť dvoch píkov pre esterifikáciu, čo je prejavom efektivity sieťovacieho činidla. Amidácia bola tiež výraznejšia pri zosieťovaných vláknach, špeciálne pre vlákna sieťované dlhú dobu a v roztoku s vyššou koncentráciou sieťujúceho činidla. Kvôli nerovnomerným vláknam, mechanické vlastnosti nevykazovali žiadnu závislosť na sieťovaní. Štúdium reológie ukázalo, že viskozita vlákna rozpusteného vo vode je menej závislá na šmykovej rýchlosti ako prášok hyaluronanu sodného rozpusteného vo vode. Napriek mnohým rôznym metódam charakterizácie vláken, ktoré boli použité v tejto práci, je stále veľa možností pre lepšiu charakterizáciu a bližšie pochopenie tohto biopolymérneho materiálu.
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Phagotrophic Phytoflagellates across Ecosystems: Their Functional Role in the Southern Ocean and Mid-Atlantic Vernal PoolsVan Kuren, Andrew, 0009-0000-7393-4689 January 2023 (has links)
Much of the world’s aquatic food webs and nutritional relationships have been blurred by the ever-increasing evidence that many phytoplankton are not exclusively heterotrophic or autotrophic, but instead mixotrophic. Mixotrophy is a continuum of different energy and carbon-acquisition mechanisms utilizing both autotrophy and heterotrophy which distorts the concept of single trophic tier modality. This makes mixotrophs flexible to adapt to environmental pressures and is becoming more the rule than the exception in many aquatic ecosystems. One unique environmental setting where mixotrophy could be highly beneficial to food web stability is in seasonally occurring ephemeral pools – aka vernal pools. Mid-Atlantic vernal pools are biodiverse biogeochemical hotspots and critical breeding habitats for a diverse number of endemic taxa including many endangered amphibian species. Vernal pools are not permanent standing bodies of water and have fluxes in hydrology, temperatures, nutrients, and irradiance to name a few. These extremes make vernal pools an ideal setting for mixotrophic phytoplankton, however it’s never been investigated. Our survey found mixotrophy in every vernal pool sampled, as well as elevated grazing rates in pools experiencing nontypical seasonal conditions. From these small-scale forest pools to the world’s oceans mixotrophy is a widespread nutritional strategy. The Southern Ocean is essential for powering worldwide ocean circulation, regional biogeochemical cycles, and global climate. One of the major hurdles with understanding mixotrophy is identifying the phytoplankton capable of shifting nutritional strategies. While many Southern Ocean plankters have been properly identified as mixotrophic, one such keystone species has gone mislabeled until now. Phaeocystis antarctica is a well-studied Haptophyte algae that plays major roles in the global carbon and sulfur cycles. This species has been historically labeled as an obligate phototroph, but contradictory survives the long dark Antarctic winter without any known evidence of encystment. We suspect that this highly abundant species is in fact mixotrophic, capable of phagocytosis to supplement the irradiance shortcomings of the Antarctic dark. We experimented with varying degrees of light and nutrient limitations to determine possible triggers for P. antarctica grazing. Our results showed P. antarctica ingesting in every treatment, but its highest grazing rates corresponded with limitations to its primary photosynthetic mode. Apart from the newly realized complexity P. antarctica brings to the Southern Ocean food web, it is an environment that suffers from microplastic pollution that can impede these mixotrophic species. Mismanaged plastic waste around the world, especially microfiber discharge from laundered synthetic textiles, escape into the natural environment, and eventually concentrate in the oceans. The Southern Ocean can become disproportionately polluted in regions due to microfibers becoming sequestered once crossing the Antarctic circumpolar current and even becoming trapped in sea-ice formations. While it is easy to see the devastation plastic waste has on megafauna (i.e. turtles, fish, birds, and whales), its microscopic devastation is less obvious. Plastic waste comes in many forms and one less researched form is buoyant polyester microfibers <1mm that interact with colony forming algae. We utilized different concentrations of polyester microfibers and mixing speeds to determine if microfiber interactions with colony formations increases or decreases overall colony buoyancy. Smaller concentrations of polyester microfibers can impart a positively buoyant effect onto P. antarctica colonies regardless of mixing speed, however larger concentrations negatively affected colony buoyancy regardless of mixing speed. / Biology
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Effects of Microplastic Exposure on the Freshwater Crustacean, <i>Daphnia magna</i>Lough, Alexis N. January 2019 (has links)
No description available.
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Microplásticos têxteis : emissão de fibras sintéticas na lavagem doméstica / Textile microplastics: synthetic fibers\' emission during domestic washingsCesa, Flavia Salvador 23 August 2017 (has links)
Há tempos a ubiquidade dos materiais plásticos no meio ambiente é assunto de discussão, com destaque para as partículas menores, ditas microplásticos (< 5 milímetros). Fibras provenientes de materiais têxteis são um subgrupo dos microplásticos e têm origem em diversas fontes, incluindo lavagens domesticas, uma vez que filtros de lavadoras e sistemas de tratamento de esgoto não são desenhados especificamente para retê-las. Quando no meio ambiente, estes materiais podem alcançar concentrações até milhares de unidades por metro cúbico, ficando disponíveis a uma gama de espécies. Neste cenário, o presente estudo teve como objetivo avaliar parâmetros de lavagem, e características têxteis que pudessem influenciar no desprendimento de fibras em efluentes de lavadoras domesticas. Foram realizados experimentos com dez sucessivas lavagens individuais, com e sem detergente, para quatro tipos de artigo: algodão (como padrão de comparação), acrílico, poliéster e poliamida. Os efluentes foram então filtrados (< 1 milímetro, 500 mícrons, 63 mícrons, 8 mícrons) e pesados. Resultados demonstram que todos os artigos têxteis liberaram fibras na lavagem. Dez sucessivas lavagens representaram queda na massa desprendida, bem como o uso de detergentes em comparação a lavagens sem detergente. Diferenças entre artigos sugeriram variação conforme características têxteis, onde algodão liberou mais fibras, seguido de acrílico, poliamida e poliéster. Em relação ao tamanho das fibras, a maioria ficou retida no filtro da lavadora (< 1 milímetro) e na peneira de 63 mícrons, mostrando o potencial de diminuição de porosidade do filtro. A visualização de fibras em papel-filtro de 8 mícrons sugere a existência de fibras micro e nano. Convertendo massa para numero de unidades, a lavagem individual de um artigo têxtil mostrou desprender entre milhares e centenas de milhares de fibras. Para uma extrapolação mundial, cerca de 40,4 mil toneladas de algodão e 21,5 mil toneladas de fibras sintéticas seriam liberadas em efluentes de esgoto. No Brasil estes valores corresponderiam, respectivamente, a 1,6 mil e 860 toneladas ano. Caso fossem tratadas em estações de tratamento de esgoto em condições ideais, seriam liberadas, em um ano, cerca de 737 toneladas de fibras sintéticas em escala mundial e 29 toneladas em escala nacional. Uma vez em cursos d\'água, estas fibras atingiriam, em ultima instância, o ambiente marinho, indicando a necessidade por soluções que combatam este tipo de poluição, sem antes deixar de explorar as lacunas do conhecimento, relacionadas, no âmbito têxtil, especialmente às diferenças metodológicas entre os estudos. / Since decades, the ubiquity of plastic materials in the environment has been a matter of discussion. Smaller pieces, named microplastic (< 5 millimeters) gained more attention recently and are now the focus of several studies. Textile fibers are a subgroup of microplastics and can be originated from several sources, including domestic washings, once filters and sewage treatment plants are not specifically designed to retain them. In the environment, these materials can reach concentrations up to millions of units per cubic meter, being available to many species. The objective of the present study was to evaluate washing parameters and also textile characteristics, which could influence in fibers emission from domestic washing machines. Experiments were done in ten successive times, with and without detergent, for four types of articles: cotton (as a pattern for comparison), acrylic, polyester and polyamide. Resulting effluents were then filtered in different porosities (< 1 millimeter, 500 microns, 63 microns, 8 microns), weighted, related to mass of textile articles and simulated regarding number of fibers. Results demonstrated that all textile articles emitted fibers during domestic washings. Ten successive washings represented a decrease in the emitted mass, as well as the use of detergent in relation to washings without the product. Differences between articles suggested variation of results according to textile characteristics, where the ranking of emission was: cotton, acrylic, polyamide and polyester. When considering the size of fibers, the majority was retained in the filter of the washing machine (porosity < 1 millimiter) and in 63 microns sieve, when compared to 500 microns sieve, showing the importance of the filter of the washing machine and the potential to decrease its porosity. Fibers retained in the filter- paper of 8 microns, couldnt be weighted because of its low mass, but their visualization suggests the existence of fibers in micro and nano scales. Converting mass to number of fibers, one individual washing was responsible for something between thousands and hundred of thousands of units. When extrapolating values to a global perspective, it reaches something around 40.4 thousand tonnes of cotton per year and 21.5 thousand tonnes of synthetic fibers per year. In a Brazilian perspective, these values correspond, respectively, to 1.6 thousand tonnes year and 860 tonnes year. If this effluents were all treated in sewage treatment plants, in ideal conditions, still they would release something like 737 tonnes of synthetic fibers per year in a global scale and 29 tonnes of synthetic fibers per year in a national scale. Once in water bodies, those fibers would reach the marine environment, indicating the necessity of solutions that could impair this kind of pollution, not before solving knowledge gaps, specially related, in the textile area, to methodology differences between studies
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MEMS-based nozzles and templates for the fabrication of engineered tissue constructsNaik, Nisarga 15 November 2010 (has links)
This dissertation presents the application of MEMS-based approaches for the construction of engineered tissue substitutes. MEMS technology can offer the physical scale, resolution, and organization necessary for mimicking native tissue architecture. Micromachined nozzles and templates were explored for the fabrication of acellular, biomimetic collagenous fibrous scaffolds, microvascular tissue structures, and the combination of these structures with cell-based therapeutics. The influence of the microstructure of the tissue constructs on their macro-scale characteristics was investigated.
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Microplásticos têxteis : emissão de fibras sintéticas na lavagem doméstica / Textile microplastics: synthetic fibers\' emission during domestic washingsFlavia Salvador Cesa 23 August 2017 (has links)
Há tempos a ubiquidade dos materiais plásticos no meio ambiente é assunto de discussão, com destaque para as partículas menores, ditas microplásticos (< 5 milímetros). Fibras provenientes de materiais têxteis são um subgrupo dos microplásticos e têm origem em diversas fontes, incluindo lavagens domesticas, uma vez que filtros de lavadoras e sistemas de tratamento de esgoto não são desenhados especificamente para retê-las. Quando no meio ambiente, estes materiais podem alcançar concentrações até milhares de unidades por metro cúbico, ficando disponíveis a uma gama de espécies. Neste cenário, o presente estudo teve como objetivo avaliar parâmetros de lavagem, e características têxteis que pudessem influenciar no desprendimento de fibras em efluentes de lavadoras domesticas. Foram realizados experimentos com dez sucessivas lavagens individuais, com e sem detergente, para quatro tipos de artigo: algodão (como padrão de comparação), acrílico, poliéster e poliamida. Os efluentes foram então filtrados (< 1 milímetro, 500 mícrons, 63 mícrons, 8 mícrons) e pesados. Resultados demonstram que todos os artigos têxteis liberaram fibras na lavagem. Dez sucessivas lavagens representaram queda na massa desprendida, bem como o uso de detergentes em comparação a lavagens sem detergente. Diferenças entre artigos sugeriram variação conforme características têxteis, onde algodão liberou mais fibras, seguido de acrílico, poliamida e poliéster. Em relação ao tamanho das fibras, a maioria ficou retida no filtro da lavadora (< 1 milímetro) e na peneira de 63 mícrons, mostrando o potencial de diminuição de porosidade do filtro. A visualização de fibras em papel-filtro de 8 mícrons sugere a existência de fibras micro e nano. Convertendo massa para numero de unidades, a lavagem individual de um artigo têxtil mostrou desprender entre milhares e centenas de milhares de fibras. Para uma extrapolação mundial, cerca de 40,4 mil toneladas de algodão e 21,5 mil toneladas de fibras sintéticas seriam liberadas em efluentes de esgoto. No Brasil estes valores corresponderiam, respectivamente, a 1,6 mil e 860 toneladas ano. Caso fossem tratadas em estações de tratamento de esgoto em condições ideais, seriam liberadas, em um ano, cerca de 737 toneladas de fibras sintéticas em escala mundial e 29 toneladas em escala nacional. Uma vez em cursos d\'água, estas fibras atingiriam, em ultima instância, o ambiente marinho, indicando a necessidade por soluções que combatam este tipo de poluição, sem antes deixar de explorar as lacunas do conhecimento, relacionadas, no âmbito têxtil, especialmente às diferenças metodológicas entre os estudos. / Since decades, the ubiquity of plastic materials in the environment has been a matter of discussion. Smaller pieces, named microplastic (< 5 millimeters) gained more attention recently and are now the focus of several studies. Textile fibers are a subgroup of microplastics and can be originated from several sources, including domestic washings, once filters and sewage treatment plants are not specifically designed to retain them. In the environment, these materials can reach concentrations up to millions of units per cubic meter, being available to many species. The objective of the present study was to evaluate washing parameters and also textile characteristics, which could influence in fibers emission from domestic washing machines. Experiments were done in ten successive times, with and without detergent, for four types of articles: cotton (as a pattern for comparison), acrylic, polyester and polyamide. Resulting effluents were then filtered in different porosities (< 1 millimeter, 500 microns, 63 microns, 8 microns), weighted, related to mass of textile articles and simulated regarding number of fibers. Results demonstrated that all textile articles emitted fibers during domestic washings. Ten successive washings represented a decrease in the emitted mass, as well as the use of detergent in relation to washings without the product. Differences between articles suggested variation of results according to textile characteristics, where the ranking of emission was: cotton, acrylic, polyamide and polyester. When considering the size of fibers, the majority was retained in the filter of the washing machine (porosity < 1 millimiter) and in 63 microns sieve, when compared to 500 microns sieve, showing the importance of the filter of the washing machine and the potential to decrease its porosity. Fibers retained in the filter- paper of 8 microns, couldnt be weighted because of its low mass, but their visualization suggests the existence of fibers in micro and nano scales. Converting mass to number of fibers, one individual washing was responsible for something between thousands and hundred of thousands of units. When extrapolating values to a global perspective, it reaches something around 40.4 thousand tonnes of cotton per year and 21.5 thousand tonnes of synthetic fibers per year. In a Brazilian perspective, these values correspond, respectively, to 1.6 thousand tonnes year and 860 tonnes year. If this effluents were all treated in sewage treatment plants, in ideal conditions, still they would release something like 737 tonnes of synthetic fibers per year in a global scale and 29 tonnes of synthetic fibers per year in a national scale. Once in water bodies, those fibers would reach the marine environment, indicating the necessity of solutions that could impair this kind of pollution, not before solving knowledge gaps, specially related, in the textile area, to methodology differences between studies
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Eletrofiação no preparo de sensor eletroquímico a base de nanotubos de carbono / Electrospinning in the preparation of electrochemical sensor based on carbon nanotubes.Rosenberger, Andressa Giombelli 01 March 2017 (has links)
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Previous issue date: 2017-03-01 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Fundação Araucária de Apoio ao Desenvolvimento Científico e Tecnológico do Estado do Paraná (FA) / Water is a vital element in human health and a determining factor in the pace of human evolution; however, the presence of emerging pollutants threatens its quality and may endangers the well-being of people and the environment. This work stands out for the development of a composite material based on nanotechnology to be used as an electroanalitic sensor in aqueous solutions with the Metronidazole drug which is considered an emerging pollutant. Initially the polymeric fibers were produced based on ecovio® and carbon nanotubes multilayer (MWCNT’s). In order to evaluate the parameters that could interfere in the process of electrospinning and to understand the interaction between the polymer and the MWCNT’s, a fractional factorial design and physicochemical characterizations analysis were used, which were: optical micrography scanning electron microcopy (SEM), mechanical analysis, wettability by contact angle, Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), differential thermal analysis (DSC) and X-ray diffraction. For the porpuse of fabricating the sensor, the fibers were calcinated and the obtained residue was characterized by SEM and FTIR. The statistical data and the images of optical microscopy and SEM showed that the addition of MWCNT’s is the parameter that most influences the diameter of the obtained microfibers (1.16 ± 0.22 µm) so that their presence decreases the diameter and results in fibers more uniform and homogeneous. After selecting the ideal conditions an experiment was done with the following process and solution parameters: concentration of ecovio® 15,00% (m/v) and MWCNT’s 0,60% (m/v); flow: 1.80 mL.h-1; distance: 16 cm and applied voltage: 18 kV. The morphology and diamater os the fibers was obtained using SEM images and showed an average diameter of 1.59±0.61 µm. It was also demonstrated a better mechanical performance after the addition of MWCNT’s to the fibers, so that they presented greter elasticity (180%) and significant increase on the elastic resistance (163%) and tensile strength (107%), besides the analysis of wettability from the contact angle suggest that the carbon-based nanomaterial is inside the polymeric microfibers. The interactions between the MWCNT’s and the polymer were better evaluated by vibracional aspects by Fourier transform infrared spectroscopy (FTIR) and showed the interaction between the MWCNT’s and the functional group C=O characteristic of the group ester of the polymers. The analysis of thermogravimetry (TGA) demonstrated a higher stability. The thermogravimetric analysis (TGA) showed a higher stability of the poly (lactic acid) component and lower resistances of the poly (butylene adipate co-terephtalate) component in the polymer blend. Besides it was necessary a constant temperature of 550 ºC during 50 minutes to the total degradation of the polymer. By differential thermal analysis (DSC) it was possible to confirm the interactions proposed by FTIR and TGA, which indicate that the interaction occurs preferentially with the aliphatic chains of the ecovio® polymer. After the calcination of the fibers, the obtained residue was characterized by FTIR and MEV and variations in the characteristics of pure MWCNT's can be observed, with reduction of the corboxylic groups for the calcined and electrospun/calcined MWCNT's, as well as the formation of lamella for the MWCNT's electrospun/calcined. The electrochemical measurements using the cyclic voltammetry technique showed that the sensor is promising for determination of Metronidazole. / A água é um elemento vital e determinante no ritmo da evolução humana, contudo a presença de poluentes emergentes ameaça sua qualidade e põe em risco o bem estar humano e ambiental. O presente trabalho destaca-se por desenvolver um material compósito formado por poli (butileno adipato co-tereftalato) (PBAT) e poli (ácido lático) (PLA) para ser utilizado como sensor eletroanalítico em soluções aquosas contendo o fármaco metronidazol. Inicialmente produziu-se fios poliméricos a base de ecovio® e nanotubos de carbono de paredes múltiplas (MWCNT’s). A fim de avaliar os fatores interferentes do processo e compreender a interação entre o polímero e os MWCNT’s utilizou-se um planejamento fatorial fracionário e análises de caracterização físico-química tais como: micrografia ótica, microscopia eletronica de varredura (MEV), análise mecanica, molhabilidade por angulo de contato, espectroscopia vibracional de infravermelho por transformada de Fourrier, análise termogravimétrica (TGA), calorimetria exploratória diferencial (DSC) e difratometria de raio X (DRX).Para a construção do sensor eletroquímico as fibras foram calcinadas e o resíduo obtido foi caracterizado pelas ténicas de MEV e FTIR. Os resultados estatísticos em conjunto com as imagens de microscopia ótica e MEV demonstram que a adição de MWCNT’s é o parâmetro que mais influência no diâmetro das microfibras (1,16 ± 0,22 µm) obtidas, de modo, que sua inserção diminui este parâmetro deixando as fibras mais uniformes e homogêneas. Após a escolha das condições ideais procedeu-se um experimento com os seguintes parâmetros da solução e do processo de eletrofiação: ecovio® 15,00% (m/v) e MWCNT’s 0,60% (m/v); fluxo: 1,80 mL.h-1; distância: 16 cm e tensão: 18 kV. A morfolagia e o diâmetro das fibras foram realizadas usando as imagens de MEV e apresentam diâmetro médio de 1,59±0,61 µm. Foi evidenciado também um melhor desempenho mecanico após a inserção de MWCNT’s às fibras de modo que as fibras apresentam maior elasticidade (180%) e um aumento significativo da resistência elástica (163%) e tensão de ruptura (107%). Ademais a análise de molhabilidade por ângulo de contato sugere que o nanomaterial a base de carbono encontra-se no interior das microfibras poliméricas. As interações entre o MWCNT’s e os polímeros foram melhor avaliadas pelos espectros vibracionais de infravermelho por transformada de Fourrier (FTIR) e evidenciam a interação entre MWCNT’s e o grupamento funcional C=O, característicos dos grupamentos ésteres dos polímeros. As análises de termogravimetria (TGA) demonstram uma maior estabilidade do componente poli (ácido lático) e uma menor estabilidade do poli (butileno adipato co-tereftalato) na blenda polimérica, além disso, foi necessário uma temperatura constante de 550 ºC durante 50 minutos para degradar totalmente o polímero.Pela análise térmica diferencial (DSC) foi possível confirmar as interações propostas pelo FTIR e TGA, que indicam que a interação ocorre preferencialmente com as cadeias alifáticas do polímero ecovio®. Após a calcinação das fibras, para o preparo do sensor, o resíduo obtido foi caracterizado por FTIR e MEV e pode-se observar mudanças na caracteristica dos MWCNT’s puros com diminuição dos grupos carboxilicos para os MWCNT’s tratados termicamente e eletrofiados/calcinados, além da formação de lamelas para o MWCNT’s eletrofiados/calcinados. As medidas eletroquímicas usando a tecnica de voltametria cíclica, mostram que o sensor é promissor para determinação de metronidazol.
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