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Design of single-crystal sample holder for high-frequency electron paramagnetic resonance
Gabriš, Andrej ; Kern, Michal (referee) ; Sojka, Antonín (advisor)
This bachelor's thesis discusses the design and manufacture of non-resonant sample holder for the study of oriented crystals, which is used for high-frequency electron paramagnetic resonance (HF-EPR). The first part of the thesis is a theoretical introduction to EPR with the application of high frequency (80-1100 GHz) and high magnetic field (16 T). This work further analyzes the topic of crystal samples anisotropy and introduces the review of materials suitable for a sample holder, which is used in low-temperature conditions (4 K). The practical part of the thesis deals with the constructional design of the rotary sample holder. This section also compares the manufacturing possiblities of the selected parts of the sample holder: machining (milling and turning) and 3D printing. Lastly, this work describes the development of the user interface for automatization of an EPR spectrum measurement.
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Reactive extrusion of polymers by peroxides
Červený, Ladislav ; Petruš, Josef (referee) ; Kučera, František (advisor)
Diploma thesis deals with processing of two types of PP, HDPE, LDPE, PET, PA, PS, PMMA and ABS by reactive extrusion in presence of peroxides. The theoretical part summarizes existing knowledge about processing of used polymers. Reactive extrusion was carried out with a single screw extruder at 260 °C, 30 rpm and 60 rpm depending on peroxide used. One type of PP was processed in presence of Luperox 101, hydrogen peroxide, dicumyl peroxide and potassium persulfate. Luperox 101 and hydrogen peroxide were chosen for reactive extrusion of other polymers. The efficiency of selected peroxides on radical modifications of individual polymers during processing was evaluated by methods of rheological (MFI), structural (FTIR) and thermal (DSC) analysis.
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Design of manufacturing technology for plastic lever
Adamec, Lukáš ; Orel, Daniel (referee) ; Kandus, Bohumil (advisor)
The aim of this project is to design the most suitable technology for manufacturing of the set component. The project contains theoretical and practical part. The theoretical part deals with division of polymer material and the description of the technology suitable for production of the set component. The practical part concentrates on the mould design of the set component including calculations and needed technological parameters of injection moulding operation.
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Polymers for health care and medicine
Jahodová, Daniela ; Ročňáková, Ivana (referee) ; Němec, Karel (advisor)
This bachelor thesis discusses polymers that are used in medicine and healthcare. In general, it addresses the field’s already known products and their possible further research and spreading of their use. Most people imagine medical polymer applications mainly in the forms of syringes, catheters, latex gloves, and the like. This text’s goal is to point out how much potential there is in further research of the material allowing for qualities as varied as biodegradable pill coating and high resistant dental implant.
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Use of polymers in road constructions
Klusková, Jana ; Komenda, Radek (referee) ; Stehlík, Dušan (advisor)
The diploma thesis deals with the use of recycled polymers in asphalt mixtures. In the theoretical part of the thesis there is discussed the global issue of plastic waste including the experience of foreign countries, where this technology has already been introducted and used. The practical part is devoted to the proposal of using recycled plastic in asphalt mixture, description of used laboratory tests and the evaluating the effect of low-density polyethylen (LDPE) on the asphalt mixture type AC. There were performed tensile strenght tests, water resistant tests and stiffness modulus tests in the laboratory (E). The output of this work is an evaluation of measured values, processing of results and their interpretation depending on the possible use of this technology in Czech republic.
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Defects at injection molding
Kuchař, Petr ; Kandus, Bohumil (referee) ; Žák, Ladislav (advisor)
The aim of this bachelor thesis was a literary study of defects created in the injection molding process of plastic materials. The study of the injection technology itself was carried out in the first part of this work. Second part of this thesis is focused on the study of defects accompanying the plastic injection process, their distribution, description, causes of the origin and possibilities of repair. Among the most problematic obvious defects accompanying the plastic injection process are the weld lines and the defects associated with. In the case of hidden defects, it is particularly internal tension. The individual defects are supplemented by suitable pictures and tables for more clarity and transparency, where the causes of the origin and the possibility of repairing specific defects are more analyzed.
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Study of biocompatible polymers degradation
Oborná, Jana ; Márová, Ivana (referee) ; Vávrová, Milada (advisor)
This bachelor thesis is focused on biocompatible polymers degradation study. Both poly(D,L-lactic-co-glycolic acid)-g-polyethyleneglycol-g-poly(D,L-lactic-co-glycolic acid) copolymers and their forms modified with itaconic acid were monitored. This work verified the optimal analytical procedure for monitoring the degradation of investigated copolymers. Bio-degradation of polymers occured at 37 °C in phosphate buffer with pH=7.4. High performance liquid chromatography with UV-VIS detection of diode-array type was used for determation of the degradation products. Gel permeation chromatography with refractive index detector was used for the assesment of the change of molecular weight polymer chain after the degradation.
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