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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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Waste Recycling Possibilities of Rigid PU Foams from the Production of KingSpan CZ
Figalla, Silvestr ; Kučera, František (referee) ; Petrůj, Jaroslav (advisor)
The theoretical part of the bachelor thesis evaluates methods and trends of recycling polyurethane materials with the emphasis on rigid polyurethane foams used as thermo isolation building material. The experimental part is focused on glycerol process verification as an alcoholization agent in the regenerative process of polyol, together with perspective microwave heating of reaction mixture. The final part of the work suggests further steps in the development of above mentioned process with the aim of its transforming into technical practice.
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The Study of Ethyllactate Synthesis from Lactic Acide Salts
Hlavatá, Daniela ; Figalla, Silvestr (referee) ; Petrůj, Jaroslav (advisor)
This diploma thesis deals with senthesis of lactic acid ethyl ester from slats of lactic acid. The literature review has been processed in the theoretical part of the diploma thesis. It is focused on manufacturing technologies of lactic acid esters, mainly on ethyl lactate by conventional and non-conventional ways of producing. Also the literature review involves producing of lactic acid and slats of lactic acid by fermentation because subsequently is possible produce ethyl lactate from that two substances. The laboratory apparatus for preparation of ethyl lactate and methyl lactate has been designed, realized and verificated function of it in the experimental part. There were carried out laboratory experimnets for production ethyl lactate and methyl lactate in this apparaturs.
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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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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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Processing stability of polyhydroxybutyrate (PHB)
Palkovský, Radim ; Figalla, Silvestr (referee) ; Tocháček, Jiří (advisor)
The aim of this thesis was to observe and to evaluate the effects of selected additives on stabilization of two poly-3-hydroxybutyrates - Biomer and Hydal. In the experimental section of the thesis,the physical properties of pure polymers, polymers with mixture of polylactid acid, boron nitride and Citroflex 4A as well as the samples with five different additives which were added to this mixture, were meassured. Whilst processing the samples, the torque inside of the kneader was recorded. Tensile strength, Young´s modulus and relative extension were evaluated using tensile tests. Next, the differential scanning calorimetry was used to determine the melting points and their changes in comparison to the pure polymers. To evaluate the thermooxidative stability, method of induction periods was used, where the amount of time needed for degradation to make the material brittle was observed and recorded. These methods determined the the Stabilizer 9000 (Raschig) as the most suitable, owing to its better thermooxidative stability and considerable relative extension. As for DHT-4A on the other hand, it was proven that within P3HB it supports degrading processes, which devaluate the processing properties of this material even more. Amongst the other additives no significant influence on the material was observed and the changes of properties were attributed to the mixture of PLA and the other substances.
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Preparation and characterisation of coatings for controlled-release fertilizers
Jašek, Vojtěch ; Sedláček, Petr (referee) ; Figalla, Silvestr (advisor)
The literary research of this Master's thesis is dedicated to controlled-release fertilizers (CRF). There is written the description of particular representatives of this kind of fertilizer and it also contains principles of nutrition's release mechanisms. Theoretical part is mainly focused on coated fertilizers, materials used for their production, coating technological processes and on a mathematical description of the diffusion transport which is the key of the mass transfer through polymer coatings. The laboratory preparation of innovative coatings based on modified vegetable oils is the main part of the experimental part of the thesis. It consists of the precursors' synthesis which can be applied on the fertilizer's surface in a liquid phase and polymerized by the UV-radiation in combination with an appropriate photoinitiator. There is described the synthesis of additional modifiers of precursors' viscosity and coatings' diffusive properties based on bio-source reactants such as sorbitol or ethyl lactate. The synthesized products are characterized by various methods such as volumetry, FTIR method or viscosimetry. The last part of the thesis contains the description of diffusive characteristics of coatings prepared out of the synthesized precursors.
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Preparation and optimization of biocomposite material for pultrusion processing
Sousedík, Jan ; Figalla, Silvestr (referee) ; Menčík, Přemysl (advisor)
This thesis focused on the synthesis and subsequent use of polyester resin from renewable natural resources as a matrix for a biocomposite with flax fibre reinforcement. The synthesized bio-based resin was characterized by mass spectrometry (MS) and Fourier-transform infrared spectroscopy (FTIR). The pultrusion was method chosen for the preparation of the composite materials. The optimalisation of the individual components of the composite was carried out as part of the thesis. Two types of composite material were prepared, a composite with fibres surface modified by acetylation and a reference composite with unmodified fibres. The resulting composites were subjected to mechanical properties tests, namely three-point flexural test, tensile test, short beam shear test (SBS), Charpy impact test and dynamic mechanical analysis (DMA). The thermal properties were investigated by differential scanning calorimetry (DSC), heat distortion temperature test (HDT) and thermogravimetric analysis (TGA). In addition, the reinforcement adhesion was monitored by scanning electron microscopy (SEM). Determination of the water absorption of the composites was also carried out. Based on the results of the analyses, a positive effect of the surface treatment of fibres by acetylation on the mechanical properties of the composites was demonstrated.
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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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