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Synthesis of polymer precursors based on isosorbide
Šichnárek, Vojtěch ; Cigánek, Martin (referee) ; Figalla, Silvestr (advisor)
The theoretical part of the thesis deals with the description of reduced hexitols, methods of isosorbide production and its application purpose in polymer materials. It includes a description of the glucose dehydration process, the influence of reaction conditions and the catalysis of the isosorbide production, the polymerization of isosorbide monomers and their properties. The experimental part of the work is focused on the optimization of isosorbide’s laboratory synthesis‘ reaction conditions, the description of its chemical modification to polymerizable isosorbide derivatives and the physical-chemical characterization of the produced molecules. The synthesis of isosorbide is monitored by LC-MS, the product is subjected to various refining methods and a detailed structural characterization. GC was chosen for the monitoring of the preparation of isosorbide dimethacrylate and structural verification of the diester was confirmed by FT-IR, MS and NMR. The physical-chemical characterization of the prepared isosorbide dimethacrylate consists of the description of its rheological properties in mixture with a commercial methacrylated oil and the study of the reactivity of the monomers by DSC. The mixture of methacrylated oil and isosorbide dimethacrylate was used to prepare polymer thermosets which were analyzed by thermo-mechanical methods such as DMA, bending and TGA. The highest isosorbide conversion achieved value of 81.9 % after 5 hours, and it reached 94,1 % for isosorbide dimethacrylate after 8 hours. According to the results, isosorbide dimethacrylate possesses the abilty to reduce the shear viscosity of polymerizable precursors and to increase the glass transition temperature and crosslinking densities of polymer thermoset.
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Preparation of methacrylated hydroxybutyrates monomers and polymers
Liška, Marek ; Mgr. Petra Zbořilová, Ph.D (referee) ; Figalla, Silvestr (advisor)
The aim of this work is the study, design, and preparation of methacrylated derivatives of poly(3-hydroxybutyrate) and the subsequent preparation of polymers from the prepared precursors. A total of six compounds were prepared. The prepared compounds include methyl-3-hydroxybutyrate and ethyl-3-hydroxybutyrate prepared by alcoholytic depolymerization with monofunctional alcohol and their methacrylated derivatives. The preparation of ethylene glycol terminated oligomer of 3-hydroxybutyrate prepared via depolymerization using ethylene glycol in two ways is also an essential part of the work. The first way involves depolymerization using conventional heating and the second one explores the preparation of a series of oligomers with different molecular weights using microwave heating. Methacrylated derivatives of the prepared oligomers were also prepared. The prepared compounds and their actual preparation are characterized using multiple analytical methods including VPO, NMR, GPC, FT-IR, LC-MS, and DSC. A series of polymers were obtained from the prepared compounds by radical polymerization using purple light (with wavelength 405 nm) as the energy source. The prepared polymer networks were characterized by DSC and their tensile strengths were tested.
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Polylactide chemical recycling to Lactide
Kučerová, Eliška ; Pospíšilová, Aneta (referee) ; Figalla, Silvestr (advisor)
This diploma thesis deals with chemical recyclation polylactide to lactide. In the theory is summarized actual state of knowledge about chemical recyclation of polylactides, their properties, preparations a possibilities of characterization. Experimental part of work verify ethanolysis of PLA withthe samples of granulate, waste filaments and textiles. In the experimental work is suggested an optimalization of alcoholysis to direct yield of oligomer suitable for depolymerization to lactide. This method was verified for 5 different samples of PLA, which 4 of them was made of waste PLA. The time needed for depolymerization was evaluated and the effect of catalysis. Lactide and PLA recyclates was further analyzed by NMR, FTIR, DSC and GPC.
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Preparation of Poly(3-hydroxybutyrate) based acrylic monomer
Liška, Marek ; Přikryl, Radek (referee) ; Figalla, Silvestr (advisor)
The main aim of this thesis is to research and prepare acrylic (methacrylic) monomers derived from poly(3-hydroxybutyrate). The monomers were prepared in two-step syntheses. In the first step P3HB was depolymerised with selected alcohols and afterwards, products of those syntheses were used as substrate and mixed with polymethylmethacrylate to produce their methacrylic derivates. The selected alcohols for the alcoholysis were ethanol and ethylene glycol. In total, four substances were prepared. Products of alcoholysis were ethyl-3- hydroxybutyrate, 2-hydroxyethyl-3-hydroxybutyrate and their methacrylic derivates. Significant part of this thesis is aimed towards the analysis of prepared substances and the analysis of reactions. In the process, titrations and instrumental methods, such as gel permeation chromatography (GPC), infrared spectroscopy (FTIR), nuclear magnetic resonance (NMR), thermogravimetry (TGA) and differential scanning calorimetry (DSC) were used. This work describes preparation and analysis of polymers prepared from methacrylates from the mentioned syntheses. Cross-linked polymers, because of their low glass-transition temperature are elastomers.
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Extraction of Poly(3-hydroxybutyrate) from Biomas
Jašek, Vojtěch ; Ing. Jiří Švrček, Ph.D (referee) ; Figalla, Silvestr (advisor)
Polyhydroxyalkanoates are a group of biopolymers which occur in cells of microorganisms. These biopolymers can be considered as alternatives to commonly used petrochemical materials such as polypropylene and polyethylene due to their physical and chemical properties. This bachelor thesis focuses on isolation of particular kind of PHA from biomass and contains both experimental and theoretical part. It consists of information about the origin and usage of PHA, challenges and problems of their biotechnological production and mainly various ways of downstream. Experimental part includes comparison of PHA extraction from biomass done by two ester solvents. Studied parameters were molecular weight of the polymer, solvent extraction ability and their resistance against hydrolysis. The main goal of this thesis was to verify the best process conditions of isolation done by nonhalogenated bio-solvent.
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Preparation and characterization of unsaturated bio-polyester resins
Žůrek, Michal ; Petrůj, Jaroslav (referee) ; Figalla, Silvestr (advisor)
The theoretical part of this work is devoted to the selection of suitable components for synthesis of a branched oligoester and their structural arrangement. Further, oligomers of lactic acid esterified with crotonic acid branched by erythritol or pentaerythritol are discussed. Crosslinking of prepared oligoesters is accomplished by free radical mechanism using vinyl acetate as reactive diluent and 2,2'-azo-bis-isobutyronitrile as initiator. Resin was cured by vinyl acetate in different mass ratios. Results show that there in an optimal ratio for curing between oligoester and reactive diluent. Using less vinyl acetate results in insufficient crosslink density or, on the contrary, using considerable excess of vinyl acetate causes rapid polymerization, that also results in lower density of crosslinking. The crosslink density was determined indirectly by extraction of the soluble part to acetone after curing and drying of the product.
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Functional foams with densit ygradient
Svatík, Juraj ; Figalla, Silvestr (referee) ; Jančář, Josef (advisor)
Vycházíme-li z lehčených přírodních materiálů, lze od porézních materiálů s gradientem porozity očekávat mechanické vlastnosti nadřazené konvenčím polymerním pěnám, a to díky jejich specifické architektuře. Tyto vlastnosti umožňují použití lehčených materiálů jako strukturních prvků. V této práci je popsaná příprava gradientních porézních materiálů pomocí laminování a/nebo 3D tisku. Provedeny byly statické a dynamické mechanické testy na obou kvazi homogenních a gradientně porézních pěnách poskytující experimentální podklad pro hypotézu deformační odezvy plynoucí ze strukturní architektury. Data se interpretovala užitím zavedených teoretických modelů. Naše výsledky vedly k závěru, že tyto teoretické modely odvozené od pěn s pravidelnou strukturou není vhodné aplikovat pro pěny s gradientem porozity, protože prokazují podstatně lepší mechanické vlastnosti než homogenně porézní pěny.
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Preparation of Ethyl 2-acetoxypropanoate
Kučerová, Eliška ; Pospíšilová, Aneta (referee) ; Figalla, Silvestr (advisor)
The bachelor thesis focuses on the preparation of ethyl 2-acetoxypropanoate as a potential nonpolar biosolvent. Selected preparation should provide the highest yield possible. For this purpose, a theoretical review of possible syntheses was developed, with emphasis on syntheses based on acetylation of ethyl lactate. The experimental part of the work then focuses in more detail on the possibility of isolating ethyl 2-acetoxypropanoate from the reaction mixture. Product isolation was verified by fractional distillation and extraction method. In the isolated product, the basic physical properties were determined and the spectrum measured by Fourier transformation infrared spectroscopy. Furthermore, the hydrolytic stability of ethyl 2-acetoxypropanoate was investigated and a series of calorimetric measurements were performed. From these measurements, the effect of reaction temperature on reaction rate and product conversion and the effect of catalyst presence was assessed.
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Effect of alternative agents on controlled degradation of polypropylene
Kadlecová, Zuzana ; Figalla, Silvestr (referee) ; Bílek, Vlastimil (advisor)
This bachelor’s thesis focuses on the effect of degradation agents in controlled rheology polypropylene and its efficiency. That was evaluated on several types of polypropylene with different molecular weight, the strength of stabilization and content of degradation reagents (organic peroxide and nitroxide Irgatec® CR 76). Melt flow rate, rheometry, and molecular weight distribution methods were applied. Results of each method for unstabilized, stabilized polypropylene and polypropylene containing degradation agent were compared. It was determined, that higher polymer chain degradation efficiency is provided by organic peroxide, lower by nitroxide. The molecular weight distribution of polypropylene was much narrower with peroxide than with nitroxide even though it should have been conversely according to published data. The molecular weight distribution of polypropylene (Mw/Mn) was much narrower with nitroxide than with peroxide at all process temperatures.
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