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Hydration of biocolloids - calorimetric study
Šméralová, Ester ; Pekař, Miloslav (referee) ; Klučáková, Martina (advisor)
Presented master's thesis focuses on the study of hydration of selected biocolloid substances, specifically humic substances (humic acids and fulvic acids), hyaluronic acid with three different molecular weight, chitosan and dextran. Interaction of biocolloids with water was studied by different methods. The effect of solubility, structure, functional groups in molecule on sorption and hydration ability of these biocolloids was investigated. In the case of hyaluronan the influence of molecular weight was also study. Differential scanning calorimetry DSC and perfusion calorimetry give results of heat of hydration, enthalpies and temperature of crystallization and melting. Thermogravimetric analysis TGA was used to determine the original moisture content of the samples.
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Mechanical propertties gel polymer aprotic electrolytes
Bárta, Vladimír ; Musil, Michal (referee) ; Sedlaříková, Marie (advisor)
This work deals with the measurement of electrical conductivity and mechanical properties of gel polymer electrolyte containing Lithium ion and their preparation. The theoretical part deals with the development of gel polymer electrolyte, their use and methods of measurement of electrical conductivity and mechanical properties. In the experimental part describes the preparation of gel electrolyte, the measurement of electrical conductivity, temperature dependence and the measurement of mechanical properties.
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Physicochemical characterization of soil humic substances isolated from modal brown soil
Churina, Iuliia ; Doskočil, Leoš (referee) ; Enev, Vojtěch (advisor)
This bachelor thesis deals with the physicochemical characterization of soil humic substances isolated from brown earth modal based on the international IHSS procedure. Humic substances are organic compounds occurring in soil and have a significant influence on soil processes and properties. The aim of this work is to obtain detailed information on the physical and chemical properties of humic substances such as mean molecular weight (Mr), spectral characteristics, elemental composition and thermal stability. Soil humic substances samples were characterized by thermal techniques such as thermogravimetric (TGA) and elemental analysis (EA). Different instrumental methods such as UV/Vis spectrometry, infrared spectrometry and fluorescence spectrometry were used to analyze the samples. The results of this work can contribute to a better understanding of soil processes and properties, which can lead to improved agricultural production and environmental protection.
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Chemical and microstructural analysis of brick samples from the object of Zákupy castle horse stables
Frankeová, Dita ; Bauerová, Pavla ; Náhunková, Pavla ; Ševčík, Radek ; Mácová, Petra ; Slížková, Zuzana ; Vondráčková, Michaela
As part of the construction-technical survey, historical brick samples were characterized using thermal analysis (TGA), scanning electron microscopy (SEM/EDS), ion chromatography (IC), infrared spectrometry (FTIR) and physical tests. The results of the tests testify to the good production quality of the masonry elements used. Based on the analyzes carried out, it can be assumed that the observed damage to the bricks is caused by high wetting of the masonry in combination with frost cycles, as well as crystallization cycles of water-soluble salts present in the surface layer of some bricks.
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Soil gel as a suitable matrix for the study of humic substances in the soil ecosystem
Černý, Pavol ; Pekař, Miloslav (referee) ; Enev, Vojtěch (advisor)
This master's thesis deals with a complex issue of soil gels. The main goal of this work is to optimize the process of isolation of soil gels out of the soil matrix. Isolation is carried out using only water and therefore represents a promising method for study of humic substances (HS) in natural form. Modal brown earth from the area of Veverské Kninice was used as a soil matrix for isolation. The isolated soil gel was phisicochemically characterized by thermal and spectroscopic methods. By using EA and TGA, the content of biogenic elements in the organic component of soil gel and the content of the inorganic component was determined. The inorganic component represents a majority share in structure of soil gel with values up to 90 % w/w. Mineralogical composition of the inorganic component was described using XRD, with quartz being the most represented. Chosen macro and microelements were determined by ICPOES and the results show a noticeable increase in the content of some elements, that form complexes with HS. Organic component was studied using spectroscopic methods FTIR and XPS, which clearly showed that the primary components of the organic matrix are HSs. For this reason, absorption coefficients EET/EBZ, E2/E3 a E2/E4 were determined using UV/Vis spectrometry. Morphology of isolated soil gels was studied by using SEM and the photographs show mineral particles covered with clusters of humic matrix.
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Study and characterization of organic substances in a biochar sample
Vojáčková, Beáta ; Kalina, Michal (referee) ; Enev, Vojtěch (advisor)
This bachelor thesis characterizes biochar from a physico-chemical point of view. The theoretical part deals with biochar as a soil conditioner, its properties, use, production, and last but not least, effect of its sorroundings. For better characterization of organic and inorganic matter a phosphate buffer was used. This buffer ensures their specific extraction due to a neutral pH. The second path is to use rainwater, which simulates the condition of the soil environment. In the experimental part are discussed both; purified buffer-extracted samples and rainwater samples, which were studied by thermogravimetric analysis (TGA), elemental analysis (EA) and by infrared spectroscopy with Fouier transform (FTIR-ATR). Conductivity and pH were also measured. Moisture and ash content, which represent the inorganic non-combustible fraction, were determined using thermogravimetry. The extraction yields were converted to ashless wt. % based on these values. Results of EA provided us with information on the content of biogenic elements and basic physico-chemical characteristics of biochar. In contrast, the FTIR method defined the presence of individual functional groups and specific constitutive units, which are present in the extracts. This information allows us to better understand the environmental impact of biochar on the soil ecosystem.
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Ionic polyacetylene type polymers and polymer networks by catalyst-free quaternization polymerization
Faukner, Tomáš
(Doctoral Thesis, 2016, Mgr. Tomáš Faukner, IONIC POLYACETYLENE TYPE POLYMERS AND POLYMER NETWORKS BY CATALYST FREE QUATERNIZATION POLYMERIZATION) The composition and structure of a series of ionic π-conjugated poly(monosubstituted acetylene)s prepared via catalyst-free quaternization polymerization (QP) of 2-ethynylpyridine (2EP) activated with equimolar amount of alkyl halide [RX = ethyl bromide, ethyl iodide, nonyl bromide and haxadecyl (cetyl) bromide] as a quaternizing agent (QA) have been studied in detail. The performed QPs gave ionic polymers well soluble in polar solvents, with approximately half of pyridine rings quaternized, which implies that also non-quaternized monomers were involved in the process of QP. The configurational structure of polyacetylene main chains was suggested based on 1 H NMR, IR as well as Raman (SERS) spectral methods. The QPs in bulk gave more expected irregular cis/trans polymers while the QPs in acetonitrile solution gave high-cis polymers. A series of prepared symmetrical bi-pyridylacetylene based monomers has been polymerized via QP approach resulting into a series of new ionic π-conjugated poly(disubstituted acetylene) type materials. It is therefore obvious that the mechanism of quaternization activation frequently applied on monosubstituted...
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