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Design of controlled nozzle for high pressure RIM head
Sýkora, Petr ; Suchý, Jan (referee) ; Koutný, Daniel (advisor)
This bachelor thesis deals with the design of mixing nozzle regulation for high-pressure mixing machine for production of polyurethane products. The aim of this work is to design the construction of controlled mixing nozzle for mixing head Cannon while keeping interchangeability with the current nozzle. I solved the chosen goal by constructing a nozzle controlled with the same build dimensions by a stepper motor. Control is ensured by throttling the flow by turning the nozzle screw through the motor. We managed to create a functional prototype and create a table to convert the existing nozzle diameters to the rotation of the engine. The main benefit of this work is the creation of an automatically regulated nozzle required for fully automated machine operation.
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Verification of setting speed and building adhesion of PU adhesives depending on external conditions
Slatinská, Jana ; Žák, Ladislav (referee) ; Kubíček, Jaroslav (advisor)
The company IFE a. S. (Knorr - Bremse) in Modřice needed to verify the curing process of glued joints with the used adhesive Sikaflex®-265. The aim was to find out whether a controlled environment is needed for curing and mainly find out influence of factors on the curing process and the velocity of building adhesion. The main factors that were investigated were temperature, humidity, the ratio of the Sikabooster® P-50 to the tested adhesive and the curing time. The result then shows which factors have an influence and which only minimal. The aim was also to verify the strength of the joint, which is stated by the manufacturer after a specific time. The impact on open technology time has not been measured.
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Modification of polyurethane by biodegradable poly(hydroxybutyrate)
Kupka, Vojtěch ; Žídek, Jan (referee) ; Vojtová, Lucy (advisor)
Cílem předložené bakalářské práce byla syntéza elastomerního polyuretanu plněného biodegradabilním polyhydroxybutyrátem. Vzorky byly podrobeny analýze morfologie pomocí rastrovací elektronové mikroskopie, mechanické vlastnosti byly testovány jednoosou tahovou zkouškou. Práce se taktéž zabývá předpovědí mechanických vlastností na základě teorií kaučukové elasticity. Bylo zjištěno, že výsledný materiál je částicový kompozit, kde se vzrůstajícím hmotnostním obsahem plniva v materiálu vzrůstá modul pružnosti. Predikce tahových křivek pomocí softwaru SEC.exe ukazovala pro reálný průběh křivky nereálné hodnoty hustot polymerních řetězců. U modelů, které vykazovaly reálné hodnoty hustot, byly naopak hodnoty napětí vyšší, než ve skutečnosti naměřené.
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Potting Compounds for Power Electronics
Štajner, David ; Červinka, Dalibor (referee) ; Vašíček, Adam (advisor)
Potting compounds are often used in electrotechnics to protect the electronics from the adverse effects, improves its insulating properties and helps to improve the heat transfer from the embedded devices in the surroundings. Embedding electronics into encapsulants extend the field of application. Such electronics can then be used in wet, dusty, corrosive or otherwise harsh environments.
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My Private Collection - "Tetraptych"
Nikitina, Pavla ; Skalický, Martin (referee) ; Gabriel, Michal (advisor)
The bachelor thesis deals with increasing and transfering texture details of abstract paintings into sculptural monochrome reliefs. My collection of 3D detail scans of abstract paintings from world-famous museums served as the basis for my work. The result is four sculptural reliefs created by robotic machining into polyurethane blocks based on the 3D scans.
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Polyurethanes in forming technology
Špičák, Pavel ; Podaný, Kamil (referee) ; Peterková, Eva (advisor)
The work carried out within the framework of Bachelor's study presents the exploration of the facts on the theme: „Polyurethanes in forming technology. It consists of the schedule, characteristics and in other part analyzes different methods of the forming which use a polyurethanes as an elastic instrument.
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Biodegradation of a new type of polyurethane using various soil substrates
Valešová, Kateřina ; Innemanová, Petra (advisor) ; Cajthaml, Tomáš (referee)
Newly developed fully aliphatic polyurethane (PUR) for agriculture applications was exposed to aerobic biodegradation in soil (ASTM D5988-18) and in modification of this method also in standardized soil which is commonly used for ecotoxicological tests. Biodegradability was assessed by measuring released CO2 during the mineralization of the test material. PUR in the natural soil (according to D5988-18) reached 43 ± 15,0% mineralization and in the standardized soil 28 ± 9,9 %. Leachates of both types of soils containing PUR (and leachates of positive controls containing cellulose and negative controls containing pure soil) were tested for ecotoxicity with a marine bacteria Vibrio fischeri after the half-year biodegradation test. The biotest was performed because of the suspicion of toxic effect of dibutyltin dilaurate, which was used as a catalyst within the PUR production. Furthermore, a reduced biodegradation experiment in two variants was carried out (with higher amount of PUR and a corresponding amount of the pure catalyst) in the standardized soil and then the leachates were tested for the ecotoxicity as well. None of the leachates showed ecotoxic effects. A PLFA analysis was performed in addition to the biotest to examine a potential impact of PUR on a microbial diversity (compared to the...
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Verification of setting speed and building adhesion of PU adhesives depending on external conditions
Slatinská, Jana ; Žák, Ladislav (referee) ; Kubíček, Jaroslav (advisor)
The company IFE a. S. (Knorr - Bremse) in Modřice needed to verify the curing process of glued joints with the used adhesive Sikaflex®-265. The aim was to find out whether a controlled environment is needed for curing and mainly find out influence of factors on the curing process and the velocity of building adhesion. The main factors that were investigated were temperature, humidity, the ratio of the Sikabooster® P-50 to the tested adhesive and the curing time. The result then shows which factors have an influence and which only minimal. The aim was also to verify the strength of the joint, which is stated by the manufacturer after a specific time. The impact on open technology time has not been measured.
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Application of renewable and recyclable raw materials for preparation of new polymers
Horák, Pavel ; Beneš, Hynek (advisor) ; Cajthaml, Tomáš (referee)
This thesis deals with optimalization of flexible polyurethane foam recycling with using of natural polyols based on rape seed oil and fish oil and it explores applications of depolymerized polyol product by formulations of new polyurethane materials. The experiments of depolymerisation showed that both tested natural oil (rape seed oil and fish oil) can be used as effective reagents for polyurethane recycling. Reaction conditions of depolymerisation were optimised with model flexible polyurethane foam and applied on waste foam from real conditions. Gain of depolymerisation is one-faze low viscosity (to 1500 mPa.s) liquid polyol products with content of hydroxyl groups ca 3 mmol/g. These polyols can be used for polymerisation of new materials. First application of recycled polyols was formulation of polyurethane foam systems. Through optimising of formula was prepared low-density semirigid foam containing 100 percentage of recycled polyol. Properties of these foams correspond to commercial foams. To prepare of homogenous cast polyurethane system based on recycled polyols it was necessary to add proper solvent, therefor extent of application has been lowered. On that account the systems were tested for study of polyaddition reaction and for following properties of the material. In these tests, the reactivity...
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Filling of Polyurethanes
Bečka, Filip ; Poláček, Petr (referee) ; Kučera, František (advisor)
Bachelor thesis focuses on preparation of filled polyurethanes, determination of tensile properties, hardness and measurement of IR spectra. Theoretical part is devoted to main components of polyurethane systems and the most common inorganic, particulate filler and summarises knowledge about application of mineral fillers into polyurethane matrix. In experimental part was developed method of application of fillers into polyurethane and test specimens were prepared. Dispersion of fillers into polyol and affected workability was investigated. For examination of test specimens 3 methods were used: FTIR spectroscopy, tensile testing and hardness measurement. FTIR spectroscopy was used to investigate conversion of free isocyanate groups an OH groups. Tensile testing proved toughness of material and tensile modulus was determinated. Conformity of strength and stress at break and also conformity of strain at strength and strain at break was found. No yield point was observed for the specimens. Hardness of specimens was measured by the Shore A method.
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