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Characterisation and chemical modification of halloysites
Vašutová, Vlasta ; Pospíšil, Miroslav (referee) ; Hradil, David (advisor)
Twelve halloysites from different sources in Slovakia, Turkey, China, New Zealand and U.S.A. have been characterized by combination of analytical methods together with the commercial sample of halloysite supplied by Sigma-Aldrich. The aim of this work was to select suitable candidates for to be used as carriers of porphyrine photoactive molecules. In nature, the formation of halloysite is related to the weathering of magmatic rocks or to the hydrothermal alteration of volcanic rocks, frequently in the contact with limestones. Halloysite belong to the kaolinite group, but, contrarily to kaolinite, it contains molecules of water in the interlayer space. It occurs in two forms: hydrated halloysite (10 ?) and dehydrated halloysite (7 ?).Dehydrated halloysites contain more admixtures than hydrated ones ? typically kaolinite, quartz, cristobalite, alunite, gibbsite and in one case also potassium mica. In samples containing both dehydrated halloysite and kaolinite their 001 diffractions overlap. Interaction with formamide was used in these cases to increase the interlayer space of halloysite and thus shift its basal diffraction to lower angles. The basal 001 diffraction of kaolinite after this treatment remains on 7 ?. Silver thiourea method (AgTU) was used to measure the cationic exchange capacity (CEC). Silver...
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Thin films prepared in RF glow discharge and their physico-chemical properties
Bránecký, Martin ; Boušek, Jaroslav (referee) ; Čech, Vladimír (advisor)
Theoretical part of this master thesis was focused on literature recherché dealing with the formation of thin films, plasma, plasma analyses using mass spectrometry and plasma polymerization. Further, this section describes the analysis of thin films using optical methods such as spectroscopic ellipsometry and FT-IR spectrometry. Experimental part describes the materials which are used for the preparation of thin films as well as a description of the equipment for preparation of thin films using a technology of plasma-enhanced chemical vapor deposition (PE-CVD). Control of deposition conditions and monitoring of plasma with its products result in high reproducibility of thin films. The last part of the thesis describes the results of measurement of the first group of samples and their ellipsometric, mass spectrometry and FT-IR evaluation with respect to the deposition conditions.
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Synthesis of SiO2/Au core/shell nanoparticles for enhancement of OCT signal
Kantorová, Martina ; Kolář, Radim (referee) ; Drbohlavová, Jana (advisor)
The aim of this master thesis is synthesis of SiO2/Au core/shell nanoparticles. These nanoparticles should improve the signal of optical coherence tomography (OCT). The procedure of nanoparticle synthesis is described in the work. Synthetized nanoparticles were analyzed by scanning electron microscopy (SEM), Ultraviolet-Visible spectroscopy (UV-Vis), Near-infrared spectroscopy (NIRS), Fourier transform-infrared spectroscopy (FT-IR) and Dynamic light scattering (DLS). Then, the synthetized nanoparticles were tested for enhancement of OCT signal. For this testing were also used commercial nanoparticles with the same structure and similar size.
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Phosphate binders
Kalina, Lukáš ; Ptáček, Petr (referee) ; Šoukal, František (advisor)
The work deals with the preparation and study of polyphosphate composites. Aluminum phosphates provide some unusual properties like high-heat resistance in terms of inorganic binders. The addition of chromium in the form of Cr2O3 or directly the bond with the aluminum-chromium-phosphate can improve the properties of this binder. Highly viscous Al2Cr(H2PO4)9 and Al3Cr(H2PO4)12 binders were prepared by dissolving Al(OH)3 and CrO3 in 85% phosphoric acid, and mixed with Al2O3 and Cr2O3 fillers. The composites were cured in the furnace at 150 °C for 24 h under pressure of 10 MPa. During the annealing at temperatures up to 1 500 °C changes in chemical structure of the cured composites were observed, leading to the understanding of the creation of crystalline phases and their eventual changes. The characterization of binders was mainly based on FT-IR, EDAX, TG-DTA and optical microscopy analyses.
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Testing of processing stability of PP-g-IA
Hampapa, Břetislav ; Tocháček, Jiří (referee) ; Kučera, František (advisor)
The Bachelor’s study is interested in processing stability of polypropylene grafting with Itaconic anhydride. A present knowledge about thermal degradation of Itaconic derivatives was summarized in theoretical part. Samples were prepared by multiple extrusions technique from virgin PP (Borsodchem, Hungary) and PP-g-IA. Die temperature 230 °C, processing time 4 minutes by 20 RPM. Qualitative and quantity analysis was made by FT-IR spectroscopy.
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