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Organic-inorganic polymers - synthesis and characterization of hybrid polymers and nanocomposites
Depa, Katarzyna ; Strachota, Adam (advisor) ; Matějka, Libor (referee) ; Sedláček, Jan (referee)
In the first part of this work, silica nanoparticles and alternative or additional filler phases were incorporated into hydrogels based on the temperature-sensitive poly(N- isopropylacrylamide) (PNIPAm). Nano-SiO2-filled porous PNIPAm hydrogels with an enhanced force response (up to 100 g) to temperature stimuli were obtained by increasing several times the pore wall thickness, which was achieved via reducing the solvent (porogen) content during the gels' cryo-synthesis. A similar optimization of the force response was also carried out for analogous gels reinforced by nano-TiO2, in which the reinforcing effect of the filler is weaker. Partial intercalation of amylopectin starch into divinyl-crosslinked bulk as well as porous PNIPAm gels several times improved their extensibility. In case of starch-rich bulk gels, a very fast and extensive one-way deswelling in response to increased temperature was achieved (re-swelling upon cooling is much slower), which is attributed to specific properties of the starch-PNIPAm interface. In doubly-filled bulk PNIPAm/nano-SiO2/starch gels, a very strong synergic reinforcing effect of both fillers is observed, due to specific hydrogen bridging between the three phases. Highly porous cryogels based on PNIPAm/nano- SiO2/starch displayed a highly improved extensibility...
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Stability of controlled drug release systems based on plasticized starch
Zhukouskaya, Hanna ; Štěpánek, Miroslav (advisor) ; Hrubý, Martin (referee)
The thesis is focused on the research of stability of controlled drug release systems based on a blend of plasticized starch/polycaprolactone (TPS/PCL) that served as a carrier. Antibiotic vancomycin was used as a model drug, and its release from TPS/PCL pellets into aqueous environment was followed by UV-spectroscopy and the obtained time dependences were treated by a simple kinetic model. Moreover, the simultaneous release of starch particles to the surrounding liquid phase was studied by static and dynamic light scattering as well as transmission electron microscopy (TEM) in order to obtain information on the stability of biodegradable matrix and on the structure of the products of the pellet decomposition on a nanoscale level. Key words: vancomycin, starch, drug delivery system, polycaprolactone (PCL), particle release, dynamic light scattering (DLS), static light scattering (SLS)
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Tissue-specific knockout of starch synthesis in columella cells of Arabidopsis thaliana and gravitropic response
Bogdan, Michal ; Fendrych, Matyáš (advisor) ; Retzer, Katarzyna (referee)
Since the studies of plant gravitropism by Charles Darwin, the identity of specific sensors of gravity in plants has been uncertain. To this date, statoliths - starch granules in the root tips - are considered to play a key role in gravity sensing. The role of statoliths as organelles that mediate the gravity sensing ability of plant roots is based on research that uses plants which have severely impaired ability to synthesize starch in general or have their cells that contain statoliths removed or damaged. This represents methodical imperfections that give rise to alternative explanations, like disturbed auxin flow due to heavy damage to the root tip or unknown involvement of starch from other parts of the plant in gravity perception. Thanks to advances in the field of CRISPR/Cas9 technology, we are now able to produce tissue-specific mutants that might help with clarification of whether starch granules in the root tip are involved in sensing gravity and if so, how significant is this involvement. This diploma thesis aimed to answer these questions by adapting the tissue-specific CRISPR/Cas9 system and using it for the creation of mutants that are starchless specifically in the columella cells. Using this approach, we generated one tissue non-specific mutant line and three tissue-specific mutant...
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Adhesion of the Hydrogels based on Poly(vinylalcohol)
Přibyl, Jiří ; Trudičová, Monika (referee) ; Kalina, Michal (advisor)
This bachelor thesis was focused on the study of adhesion properties of hydrogels based on polyvinyl alcohol using a rheometer. The used hydrogels were divided into three groups, physical, chemical, and modified with starch, PEG or gelatin. Subsequently, the adhesion properties of the hydrogels were determined using a pull off test measured on a rheometer. From the experimental results, the dependences of the adhesion properties on various parameters such as concentration, molecular weight, freezing / thawing process, amount of glutaraldehyde addition and on the type and ratio of added additive were determined. From the following results, it was found that starch is suitable as an additive for increasing the adhesion properties, and on the other side, PEG can be used to reduce the adhesion properties.
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Solubility control of biodegradable starch-based packaging
Krobot, Štěpán ; Ondreáš, František (referee) ; Lepcio, Petr (advisor)
This bachelor thesis deals with the preparation and testing of biodegradable films based on starch. The aim of the thesis is laboratory preparation of foils based on various types of starch, glycerol, polyvinylalcohol and with the addition of plasticizer – citric acid. Four different types of starch and two types of polyvinyl alcohol were used. In the first series of samples, the ratio of added glycerol to starch content was varied. Samples in the second series were prepared in the same ratios, but with different PVA. A citric acid solution was added into the last series of samples. The second aim of the thesis, after pressing the films, was to determine their solubility and stability in aqueous media depending on the ratio between added glycerol to starch content, the type of polyvinylalcohol used, and the addition of citric acid to the mixture. It has been found that citric acid appears to affect the chemical structure of the films and thus their solubility in aqueous media as well as their mechanical properties. Fourier-transform infrared spectroscopy (FTIR) was used to study the structure of the films and to elucidate its effect on solubility.
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Processing optimalization of biodegradable starch based packaging and its characterization for adaptation on production technology
Krahulová, Veronika ; Ondreáš, František (referee) ; Lepcio, Petr (advisor)
This diploma thesis focuses on the problematics of preparation of biodegradable starch based packaging. The aim of the thesis is to optimize the preparation and verify the characteristics for further adaptation and production technologies. The films consisted of starch, PVA and glycerol. Four types of starches, three types of PVA and different ratios of glycerol were tested. Films were prepared by casting with glycerol as a plasticizer, instead of distilled water, to reduce the energy cost of the preparation. The mechanical properties of the films were tested as well. The experimentally determined values of elongation at break and tensile strength of the wheat starch films were compared with a semiempirical model. Results revealed that the preparation of thermoplasticization of starch with glycerol leads to a considerable increase in elongation at break but at the same time to a marked decrease in tensile strength compared to the preparation from solution. The rheological properties of the prepared films were also investigated. Infrared spectroscopy (FTIR), thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) were used to study the structure of the films.
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Organic-inorganic polymers - synthesis and characterization of hybrid polymers and nanocomposites
Depa, Katarzyna ; Strachota, Adam (advisor) ; Matějka, Libor (referee) ; Sedláček, Jan (referee)
In the first part of this work, silica nanoparticles and alternative or additional filler phases were incorporated into hydrogels based on the temperature-sensitive poly(N- isopropylacrylamide) (PNIPAm). Nano-SiO2-filled porous PNIPAm hydrogels with an enhanced force response (up to 100 g) to temperature stimuli were obtained by increasing several times the pore wall thickness, which was achieved via reducing the solvent (porogen) content during the gels' cryo-synthesis. A similar optimization of the force response was also carried out for analogous gels reinforced by nano-TiO2, in which the reinforcing effect of the filler is weaker. Partial intercalation of amylopectin starch into divinyl-crosslinked bulk as well as porous PNIPAm gels several times improved their extensibility. In case of starch-rich bulk gels, a very fast and extensive one-way deswelling in response to increased temperature was achieved (re-swelling upon cooling is much slower), which is attributed to specific properties of the starch-PNIPAm interface. In doubly-filled bulk PNIPAm/nano-SiO2/starch gels, a very strong synergic reinforcing effect of both fillers is observed, due to specific hydrogen bridging between the three phases. Highly porous cryogels based on PNIPAm/nano- SiO2/starch displayed a highly improved extensibility...
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Preparation of polysaccharidic binders used in artworks
Švajcrová, Lenka ; Hrdličková Kučková, Štěpánka (advisor) ; Čapek Adamec, Martin (referee)
The main aim of this bachelor thesis was to prepare polysaccharide binders from the chosen kinds of starch (gained from potatoes, corn, wheat, rice and kuzu), Arabic gum and to pigment them. The created samples of the polysaccharide binders were then prepared for further investigation using liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) and Fourier transform infrared spectroscopy (FT-IR). This work is also focused on the history of the production of starch, its origin, contained substances and growing of the specific plants, from which the starch is obtained from. Furthermore, there is also described the technology process of paintings and other polychromatic arts creation. The technical character of paintings is actually determined by the binders, thus apart from the polysaccharide binders there are also described oil, protein and oil-resin binders. Key words: polysaccharidic binders, starch, Arabic gum, artworks
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Assessment of dairy management in a given farm
BRABENEC, Petr
My diploma thesis is based on the observation of dairy cows nutrition at the farm, nutrition is the most important factor in the production of milk. The introduction of my thesis is focused on a literary overview, which briefly describes the process of digestion, evaluation of nutrients in feed doses and assessment of mixed feed doses. Attention is focused on feed technology in the farm, there was evaluated the intake of dry matter by dairy cows. Dairy cows were fed by total mixed ration (TMR), samples were sent for evaluation to an accredited laboratory and compared to NRC (2001). Another criterion was the evaluation of the particle structure by the Penn state separator (2002), the results were compared with the recommended standard, there was evaluated the homogeneity of the mixed feed structure too. The thesis evaluate composition of the feed ration, where maize silage is predominanting, there is described the variability of starch in maize silage in the monitored period. The thesis describes the evaluation of ungraded starch from bovine feces, samples were again analyzed in an accredited laboratory and evaluated according to the recommended standard, and the probable causes of increased content of unstressed starch in beef excrement are described. Some of the milk production indicators are also mentioned. There was used the informations of Czech and foreign authors.
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Biodegradable plastics
Schifferová, Zuzana ; Jan, Vít (referee) ; Molliková, Eva (advisor)
The aim of this bachelor theses is to discuss the process of biodegradation occurring with biodegradable polymers including factors affecting this process. The theses also introduces some types of biodegradable plastics including their properties. At last it discusses waste management of these plastics and their ecological impact.
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