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Study of preparation and structure of nanofibers of inorganic and organic biomaterials
Ručková, Jana ; Částková,, Klára (referee) ; Cihlář, Jaroslav (advisor)
The aim of this Master’s thesis is to investigate the preparation and structure of nanofibres of inorganic and organic biomaterials. Nanofibres of polycaprolactone, chitosane and their composites with hydroxyapatite particle were prepared by centrifugal force spinning process, which uses centrifugal forces for nanofibres spinning. Designed nanofibres can be used in bone tissue engineering. Experimental activity has started with synthesis of hydroxyapatite nanoparticles and preparation of polymer solutions and composite suspensions at different concentrations. The solutions and the suspensions were characterized by density and viscosity which were changed in dependence on temperature and polymer concentration. The solutions and the suspensions were spun at varying speeds and using two different sizes of collectors. The dependence of spinneret head revolution speed, size of collectors and polymer concentration on nanofibres diameter was studied. Biological activity of polycaprolactone and hydroxyapatite/polycaprolactone nanofibres was tested by means of SBF.
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Synthesis and properties of ceramic nanoparticles based on anionic doped composite oxides of titanium
Kašpárek, Vít ; Veselý, Michal (referee) ; Cihlář, Jaroslav (advisor)
Master’s thesis deals with synthesis of anatase and its anion doping by carbo-nitridation. Prepared samples were used for testing of the photocatalytic activity. Low-temperature anatase was synthesized at 80 °C for 6 hours and carbo-nitridatation was carried out in ammonia/tetrachloromethane atmosphere at 500 °C for 3 hours. The influence of silver content on low-temperature crystallization of anatase was studied by reaction of titanium tetraisopropoxide with water. Silver nanoparticles were prepared by reduction of silver nitrate by D-glukose and sodium citrate. One of the results is the draft for one-pot synthesis of anatase by titanium tetraisopropoxide with complexing agent (sodium citrate, ammonium citrate, citric acid). The study of photocatalysis water splitting was carried out in the presence of 20 % vol. of methanol. Anatase prepared with citric acid has the highest photocatalytic activity (Pt 0,5 %) in UV/VIS spectral region. The activity achieved 38,6 % effectiveness of TiO2 standard (Degussa P25). Doping by nitrogen didn’t lead to increase of photocatalytic activity.
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Study of mechanism and kinetics of hexa-1,5-diene polymerisation catalyzed by phenoxy-imine titanium complex and MAO
Ševčík, Jan ; Cihlář, Jaroslav (referee) ; Hermanová, Soňa (advisor)
This diploma thesis is focused on study of polymerization of hexa-1,5-diene catalyzed by phenoxy-imine titanium dichloride (FI Ti) and methylaluminoxane (MAO) as cocatalyst. Effect of monomer concentration, polymerization temperature and cocatalyst/catalyst ratio on catalytic activity, molecular weights, polydispersities and particularly microstructure of prepared poly(hexa-1,5-diene) was studied. 1H NMR spectroscopy revealed that the poly(hexa-1,5-diene) microstructure contained methylene-1,3-cyclopentane (MCP) as well as vinyl tetramethylene (VTM) units. Kinetics of this polymerization was studied. Finally, copolymer of ethene and hexa-1,5-diene possessing incorporated pendant vinyl group was prepared.
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Sol-gel synthesis and properties of piezoceramic nanoparticles on the base of (BaxCa1-x)(TiyZr1-y)O3
Vacek, Petr ; Matoušek, Aleš (referee) ; Cihlář, Jaroslav (advisor)
The aim of the work was sol-gel synthesis of piezoceramic nanoparticles on the base of BaxCa1-xTiyZr1-yO3 (BCTZ), preparation of sintered samples and analysis of their structure and properties. Theoretical part includes information about piezoelectricity, piezoelectric materials and preparation of ceramics. Experimental part describes sol-gel synthesis of BCTZ nanoparticles and achieved phase composition and particle size. The next topic of experimental part was preparation of sintered BCTZ samples and analysis of their properties.
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Preparation and properties of machinable ceramic materials
Sláma, Martin ; Matoušek, Aleš (referee) ; Cihlář, Jaroslav (advisor)
The thesis is focused on studying the machinability of ceramic material in dependence on presintering temperature. Alumina was used as an experimental material. The machinability of alumina was observed on samples produced by uniaxial pressing. Presintered and not-presintered disks were machined by cutter. Disks were presintered at 700°C, 800°C, 900°C and 1000°C for one or two hours. Machinability of alumina was tested according to four levels of the milled depth and according to temperature and the effect of dwell.
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Study of bioceramic materials on the base of calcium phosphates
Kolář, Martin ; Maca, Karel (referee) ; Cihlář, Jaroslav (advisor)
The literature search on the topic of Bioceramic materials focused in layered materials based on calcium phosphates was written up. Based on knowledge obtained, experiments of preparation of calcium phosphates layered materials based on calcium phosphates by spin-coating method focused in optimalization of layer application conditions were designed and carried out. Experiments of preparation of hydroxyapatite bulk ceramics by uniaxial pressing followed by heat treatment were also performed. Prepared layered and bulk ceramics were characterized from bioactivity point of view by testing of their interaction with simulated body fluid.
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Ceramic materials with foam structure
Šenk, Vít ; Trunec, Martin (referee) ; Cihlář, Jaroslav (advisor)
Bachelor’s thesis is concerned to preparation ceramic materials with a foam structure suitable for supporting, catalytic and biological applications. A part of work is focused on preparation ceramic substrates such as alumina, zirconia and foam materials for catalytic applications based on perovskite materials. Process of preparation ceramic foam structures consists of stable ceramic slurry prepared by different methods, drying, thermal extraction and evaluating sintered structure.
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Catalytic behaviour of ceramic catalytic materials
Schlosser, Radek ; Cihlář, Jaroslav (referee) ; Cihlář, Jaroslav (advisor)
In this bachelor’s thesis the methods of preparation of ceramic perovskite-like membranes for heterogenous catalysis and reformation reactions of carbohydrates were studied. The syntetic La-Ca-Fe-Ti-O type and commercial La-Ca-Fe-Co-O type powders were used. The properties such as phase purity, specific surface area and morphology of used powders were determined. Technology of processing included powder uniaxial pressing, membrane sintering and polishing their surface. Conditions for uniaxial pressing were optimized. The dependence of grain size and amount of titanium was determined.
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Bioceramic Materials and Their Biocopatibility with Bone Tissues
Novotná, Lenka ; Trunec, Martin (referee) ; Cihlář, Jaroslav (advisor)
The thesis concerns the study of ceramic coatings of zirconia nanoparticles deposited on alumina, zirconia and glass substrates by ultrasonic spraying. The quality of deposits was investigated in dependence on the type of substrate (composition, temperature, roughness) and concentration of ceramic suspension. The best results were received by the deposition of suspension of low concentration on rough substrates at low temperatures. The biocompatibility was tested in vitro. Good cytocompatibility of ceramics with nanostructure coatings was found.
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Synthesis and Properties of Ceramic Photocatalytic Materials
Strejček, Josef ; Maca, Karel (referee) ; Cihlář, Jaroslav (advisor)
Two methods of synthesis of ceramic catalytic perovskite materials for fotochemical decomposition of water and partial oxidation of methane were studied. The method based on mechanochemical activation of oxide reactants followed high temperature solid state reaction made possible preparation of almost one phase perovskites of InVO4, InNbO4, InTaO4, EuVO4, EuNbO4 a EuTaO4. Pseudo sol-gel synthesis combined with high temperature solid state reaction lead to one phase perovskites or products with more than 90% of perovskites phase of the Sm-Ca-Co-Al-O type.
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