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The influence of PEO source on nanofiber layer preparation
Grufíková, Jana ; Knotek,, Petr (referee) ; Knotková, Kateřina (advisor)
The electrospinning process of polymer solutions is affected by many different parameters that can be divided into solution parameters, process parameters, and ambient parameters. This study is focused on characteristics of a polymer and its solution, which are ranging into the solution parameters. The aim of this study is to compare poly(ethylene oxide) characteristics in the relation to electrospinning of hyaluronic acid, to find the difference between them using available analytic, thermic and spectral methods, and to define the influence of properties on polymeric solutions behavior during electrospinning. It was find that poly(ethylene oxides) obtained from two different sources behave differently in an electrostatic field, although their molar mass is declared as the same. It was also confirmed that the electrospinning process of polymeric solutions is affected mainly by their viscosity and conductivity. This two properties are determined especially by the molar mass of polymer and also by the content of impurities or content of some another polymer during electrospinning of mixed solution.
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Influence of the polymer mixture composition on the properties of polysaccharide fibrous biomaterials
Kavčiaková, Zuzana ; Pavliňáková, Veronika (referee) ; Vojtová, Lucy (advisor)
Navrhovaná diplomová práca sa zaoberá prípravou a hodnotením vlastností vlákien na báze polysacharidu Gum Karaya a jeho zmesí s poly(vinylalkoholom), poly(vinylpyrolidínom) a poly(etylénoxidom). Diplomová práca je rozdelená na teoretickú, experimentálnu a diskusnú časť. V teoretickej časti je opísaná príprava a charakterizácia vlákien rôznej veľkosti. Experimenty zahŕňajú prípravu vlákien metódou elektrospinningu. Získané vlákna boli analyzované pomocou Fourierovej transformovanej infračervenej (FT-IR) spektroskopie, rastrovacej elektrónovej mikroskopie (SEM), dynamickej mechanickej analýzy (DMA) a gravimetrickej metódy na vyhodnotenie pomeru napúčania vlákien. Elektro-zvláknené vlákna získané z vodného roztoku organických kyselín sa osvedčili ako vhodný materiál s dostatočne dobrým priemerom vlákien a pevnosťou v ťahu.
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Influence of the polymer mixture composition on the properties of polysaccharide fibrous biomaterials
Kavčiaková, Zuzana ; Pavliňáková, Veronika (referee) ; Vojtová, Lucy (advisor)
Navrhovaná diplomová práca sa zaoberá prípravou a hodnotením vlastností vlákien na báze polysacharidu Gum Karaya a jeho zmesí s poly(vinylalkoholom), poly(vinylpyrolidínom) a poly(etylénoxidom). Diplomová práca je rozdelená na teoretickú, experimentálnu a diskusnú časť. V teoretickej časti je opísaná príprava a charakterizácia vlákien rôznej veľkosti. Experimenty zahŕňajú prípravu vlákien metódou elektrospinningu. Získané vlákna boli analyzované pomocou Fourierovej transformovanej infračervenej (FT-IR) spektroskopie, rastrovacej elektrónovej mikroskopie (SEM), dynamickej mechanickej analýzy (DMA) a gravimetrickej metódy na vyhodnotenie pomeru napúčania vlákien. Elektro-zvláknené vlákna získané z vodného roztoku organických kyselín sa osvedčili ako vhodný materiál s dostatočne dobrým priemerom vlákien a pevnosťou v ťahu.
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The influence of PEO source on nanofiber layer preparation
Grufíková, Jana ; Knotek,, Petr (referee) ; Knotková, Kateřina (advisor)
The electrospinning process of polymer solutions is affected by many different parameters that can be divided into solution parameters, process parameters, and ambient parameters. This study is focused on characteristics of a polymer and its solution, which are ranging into the solution parameters. The aim of this study is to compare poly(ethylene oxide) characteristics in the relation to electrospinning of hyaluronic acid, to find the difference between them using available analytic, thermic and spectral methods, and to define the influence of properties on polymeric solutions behavior during electrospinning. It was find that poly(ethylene oxides) obtained from two different sources behave differently in an electrostatic field, although their molar mass is declared as the same. It was also confirmed that the electrospinning process of polymeric solutions is affected mainly by their viscosity and conductivity. This two properties are determined especially by the molar mass of polymer and also by the content of impurities or content of some another polymer during electrospinning of mixed solution.
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The role of sonication of polyethyleneoxide solutions containing magnetic nanoparticles on morphology of nanofibrous mats
Peer, Petra ; Stěnička, M. ; Filip, Petr ; Pizúrová, Naděžda ; Babayan, V.
Properties of the resulting polymer nanofibers are often tailored by sonication technique applied prior or past an electrospinning process. The aim of this contribution is to evaluate morphology of nanofibrous mats formed by poly(ethylene oxide) with distributed magnetic nanoparticles (MNP) (about 20 nm in diameter) in dependence on time of sonication of the used polymer solutions. The solutions were exposed to sonication (intensity 200W, frequency 24 kHz) for 10, 30, and 60 minutes. It was shown that rheological characteristics (viscosity, storage and loss moduli) strongly depend on time of sonication (particularly phase angle) in contrast to electric conductivity and surface tension. For analysis of homogeneous distribution of MNP in polymer solution, the rheological measurements were carried out also in presence of external magnetic field. Magnetorheological efficiency (a relation of corresponding viscosities) was determined for 80, 170, and 255 mT. Consequently, changed rheological characteristics participate significantly in the process of electrospinning and resulting quality of the obtained nanofibrous mats. Qualitative changes were described by\nmeans of scanning electron microscopy (variance of mean diameter of nanofibers), transmission electron microscopy (distribution of MNP within nanofibrous mats). Static magnetic properties were determined by a vibration sample magnetometer. It was shown that even distribution of MNP in the mats can be achieved by mere sonication process without application of external magnetic field during an electrospinning process. However, time of sonication generates a degree of embedding of MNP into individual nanofibers.
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