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Fractional composition of metal ions in humic gels
Potočková, Jana ; Gregorová, Eva (referee) ; Klučáková, Martina (advisor)
This thesis deals with bond strength of metal ions in humic gels. Several samples of humic acids were studied to consider influence of samples isolation process and their consequent characteristics on bond strength of metal ions in their complexes. Some functional groups was blocked by methylation at some samples. Amount of active functional groups in individual samples was determined by standard titration methods. Metal ions bound in humic complexes were divided into several fractions by extraction with different reagents (distilled water, 1M MgCl2, 1M HCl and 0,025M NH4EDTA). Two extraction methods were used: sequential and fractional. During the fractional extraction leaching of metal ions always proceeds in single agents from original komplex, whereas during the sequential extraction leaching proceeds gradually in all extraction agents in order according to rising afinity of agents, i.e. bond strength of metal ions in samples. Amount of metal ions in leaches after extractions was analysed by UV-VIS spektrometry.
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The behavior of superabsorbent polymers in artificial soils
Männlová, Adriana ; Smilek, Jiří (referee) ; Kratochvílová, Romana (advisor)
This bachelor thesis deals with the study of superabsorbent polymers for environmental and agricultural applications. Generally thessis preparations are to perform the funciton of irrigation ,so that thanks to its unique properties , can absorb water in tha rainy season and keep it arend the root system as long as possible. Superabsorbent polymers can also perform the fiction of fertilizer carries and thus ensure its gradual release. These gel structures were subjected to testing of their swelling in environments with different ionic strenght. Subsequently, in the long term monitored thein ability to trap water in the soil environment model.
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Polysaccharide-protein gels
Hájovská, Pavla ; Smilek, Jiří (referee) ; Chytil, Martin (advisor)
This bachelor thesis deals with gelation of albumin solutions and mixed solutions of albumin and the high molecular weight hyaluronic acid due to heating. Study was carried out by measuring rheological properties of the solutions, formed gels and gelation process. For the protein samples in water, the effect of concentration, ionic strength and pH were tested. For mixed solutions, the effect of concentration and a composition of the polymeric component were tested. With increasing concentration of the polymeric component, the gel point is shifted towards lower temperature values, with the concentration difference of 2 % (w/v) up to 5°C. The resulting gels exhibit higher values of loss and storage moduli. Similar behavior was observed also in the samples influenced by the ionic strength as, a result of alternation of the electrostatic interactions between the charged groups of the polymer chains and as a result of change of this charge due to the pH reduced below the pI value of the protein.
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Hyaluronan ion complexes
Cimalová, Jana ; Sedlařík, Vladimír (referee) ; Pekař, Miloslav (advisor)
This diploma thesis is focused on the study of physical and chemical properties of hyaluronan and cationic surfactant. As the cationic surfactant Septonex was used. The influence of the environment on the system, the effect of molecular weight of hyaluronan, and its concentration was studied. Then, the study of the influence and the effects of concentration of Septonex on the interaction of hyaluronan-surfactant followed. Different methods of measurement were chosen to characterize these ionokomplexes. The critical micelle concentration of the surfactant itself was measured, and then also with the addition of hyaluronan by spectrofluorimetry with fluorescent probe pyren. It was found, that hyaluronan forms gel with Septonex. On this basis, gels were prepared for three different molecular weights of hyaluronan – 300 kDa, 806 kDa and 1697 kDa. Gels were prepared in a ratio of hyaluronan – surfactant 1:1. In gels prepared in this way, the influence of environmental water and 0.15 M NaCl was studied and it was found that at 0.15 M NaCl clear gels are formed. Selected samples of the gels were then measured with oscillatory testing and the rheological behavior of gels of Septonex was studied. As the last method the turbidimetric measurement was chosen, which characterized the turbidity point in the gradual addition of Septonex to sodium hyaluronate solution. Again, the effect of the molecular weight of hyaluronan and its concentration in two environments - water and 0.15 M NaCl was evaluated. It was found that 0,15 M NaCl suppresses formation of turbidity and formation of precipitates.
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Bond strength of metal ions in humic gels
Potočková, Jana ; Sedláček, Petr (referee) ; Klučáková, Martina (advisor)
This thesis deals with the study of bond strength of Cu2+ ions in humic gels. Two methods of extraction were used during the study, sequential and fractional extractions. During the fractional extraction leaching of copper proceeds in single agents, whereas during the sequential extraction leaching proceeds gradually in all extraction agents. Destilled water, 1M MgCl2, 1M HCl and 0,025M NH4EDTA were applied like extraction reagents. Amounts of Cu2+ ions in leaches after extraction were measured by UV-VIS spectrometry. By using extractions was obtained the fractionation of Cu2+ ions according to bond strength in humic gel.
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New gel electrolytes
Sumka, Martin ; Jahn, Michal (referee) ; Sedlaříková, Marie (advisor)
This master´s thesis deals with the properties of gel polymer electrolytes, brief characteristics of other types of electrolytes and materials that are used for preparing polymer electrolytes. The thesis explains the use of the gel electrolytes in practice, the current conduction in the electrolytes and the properties of ionic liquids, and flame retardants. This thesis also focuses on methods of measurement of mechanical properties of gel polymer electrolytes. The practical part is focused on preparation of methacrylate gel electrolytes and their modifications with the use of flame retardant - triethyl phosphate (TEP) and ionic liquid - 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide (Emim TFSI). In this part there are evaluations of their potential funcionality (potential window) and specific conductance conductivity using the method LSV (linear sweep voltammetry) and impedance spectroscopy. The practical part also includes a thermal analysis of selected samples by TGA, DTA and EGA methods.
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Hyaluronan hydrogels
Vaculíková, Hana ; Pekař, Miloslav (referee) ; Hurčíková, Andrea (advisor)
In this thesis there was preparation optimized for agarose-gelatin hydrogels with addition of various concentrations of low-molecular and high-molecular hyaluronan and than there were examined viscoelastic properties of them by rheological oscilation tests and high-resolution ultrasonic spektrometry. By rheology were measured values of elastic and viscous modulus for selected amplitude of strain, oscilation frequencies and temperatures. In the second method there were recorded values of ultrasonic velocities of samples at temperature scanning from 85 to 25 °C and from 25 to 85 °C in HR-US 102, which were compared with ultrasonic velocities measured at the temperature 27,0±0,5 °C by gel-modul HR-EX-SSC.
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Superabsorbents with controlled release of nutrients
Závodská, Petra ; Kratochvílová, Romana (referee) ; Klučáková, Martina (advisor)
This thesis is focused on the study of superabsorbent polymers and their ability of control release of nutrients. These polymers can absorb huge amount of water, up to hundredth times more than the original weight is. In combination with nutrients, especially nitrogen, phosphorus, potassium and lignohumate, they make effective fertilizer. Due to this fact, the possibility of use in agriculture is increasing. Therefore, experiments that are researching the ability of containing the water were performed, the swelling capacity was measured. Experiments that are related to control release of nutrients were performed next. Therefore, this thesis is focused on the study of superabsorbent polymer characterisation, that can be used in agriculture.
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Preparation of antimicrobial gels with plant extract and oils
Benešová, Markéta ; Hoová, Julie (referee) ; Skoumalová, Petra (advisor)
This bachelor thesis was focused on studying antimicrobial effects of natural plant extracts and their subsequent application. The research was mainly focused on the antioxidant and antimicrobial activity of plant extracts and liposomal particles with their contents. Theoretical part of thesis was focused on the topic of natural antimicrobial and antioxidant substances, problems with bacterial resistance as well as describing features and attributes of used herbs, and characterization of gels and liposomes. Within the experimental part of thesis, three types of extracts (aquatic, ethanol and oil), prepared from 10 different types of plants, were described. The content of phenolic, flavonoid substances, also antioxidant and antimicrobial activity were then determined. After that, the contents of all extracts were encapsulated into liposomes, and size, stability, encapsulation activity, also antioxidant and antimicrobial activity of those liposomes were determined. The size distribution was wide, but in terms of the measured zeta potential, most of the particles were stable. All prepared extracts and liposomes containing them were tested for their antimicrobial activity. The tests were performed on a gram-positive genus of Micrococcus luteus and a gram-negative type of Serratia marcescens. The most effective oil extracts against both species were eucalyptus and fir, as well as oil extract of cloves, along with aqueous extracts of mustard seeds, cloves and juniper, or ethanol extract of anise which also has high antimicrobial effects. Finally, these extracts and liposomes were applied into the gels, which could be found useful in the pharmaceutical industry, as an alternative to externally used antibiotics, or in the cosmetic industry.
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