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Influence of pyrrolidone derivates on alkyd and polyurethane coatings.
Klímová, Edita ; Molliková, Eva (referee) ; Tulka, Jaromír (advisor)
The aim of this thesis was to append data on chemical resistance of coatings made of paints based on alkyd and polyurethane resins. In the theoretical part, relevant information on coatings, preparation of their systems, theory of solubilization and properties of solvents were collected and organized. Three N-derivates of pyrrolidone were chosen for the practical part. Their influence on particular alkyd and polyurethane coatings was studied with emphasis on time course of coatings degradation.
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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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Sports and cultural centre, Otradov
Myška, Jan ; Nováková, Eva (referee) ; Kolář, Radim (advisor)
The subject of this diploma thesis is the preparation of project documentation for the implementation of new sports and cultural centre Otradov. The dominant feature of the complex objects stands and multipurpose hall. The building is architecturally designed with an effort to fit in too much of rural architecture. Multipurpose hall has two floors, one third roofed flat roof, two-thirds of the roof ridge. The core system is aerated concrete blocks. The building is two-storey grandstand with the carrier deck. Roofing is solved by means of broken wooden beams. Sanitary facilities is dealt wall system and roofed shed roof. Athletics track, the surface of the polyurethane mixture designed for sports.
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The Wheel of Death
Horčicová, Monika ; Chamonikolasová, Kaliopi (referee) ; Gabriel, Michal (advisor)
Bachelor thesis titled Wheel of death- Wheel of life cycle of life displays, which are inherently death. Object is part of the composition of the human skeleton in a circle, the imaginary ktrerý moves. The lower part of the wheel bends under its own gravity. The circle is a symbol of life and its cycle. The bones are a symbol of death.
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Preparation and characterization of poly-3-hydroxybutyrate copolymers
Kolomazník, Vít ; Kupka, Vojtěch (referee) ; Porubský, Tomáš (advisor)
This thesis evaluates the synthesis of copolymers based on poly-3-hydroxybutyrate (PHB). The goal is to create a material with the highest possible concetration of PHB with the smallest possible volume of crystal phase. PHB with lower molecular weight and hydroxyl end groups used for polyurethane synthesis was prepared by alcoholysis of PHB polymer with 1,4 butanediol. Polyethylene glycole (PEG) of various molar mass and ratio values was chosen in this thesis as a second reacting substance. Another substance used for copolymeration with PHB was the poly(butylene adipate-co-terephthalate) PBAT. Both variants used hexamethylenediisocyanate (HDI) as a non-toxic bonding agent. From these substances, a block copolymers comprised of soft and hard segments were formed. Hard segments are a result of PHB and it‘s crystalic structure. Soft segmets are comprised of PEG or PBAT macromolecules. The influence of soft segments of various length and molar ratio of reactants on overal polyurethane properties was evaluated. Prepared materials were charactrerized by thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and infrared spectroscopy (FTIR). Molecular weight was measured by gel permeation chromatography (GPC).
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Utilization of an elastic tool made of polyurethane in forming technologies
Zigáček, Štěpán ; Peterková, Eva (referee) ; Podaný, Kamil (advisor)
ZIGÁČEK Štěpán: Utilization of an elastic tool made of polyurethane in forming technologies This project elaborated within bachelor study program B-STI Mechanical engineering is literary study focused on manufacturing methods of forming by elastomers. The recherche deals with the basic division and principles of all possible utilizations of elastomers focusing on the usage of polyurethane with examples and evaluation of their advantages and disadvantages.
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Specifics of forming using elastomers
Barák, Vít ; Peterková, Eva (referee) ; Podaný, Kamil (advisor)
The thesis contains a review of methods using elastomer tool, including the distribution of tools and suitability to the operations. Forming using elastomers is among the unconventional forming methods using flexible tool which is especially suitable for sheet metal forming. The material is used rubber and polyurethane. There are described properties, forming forces and other attractions of elastomers. The principle consists in replacing the fixed part of the tool flexible medium. Forming methods are divided to open tool forming and close tool forming, according to the construction of forming tool. Open tool forming includes bending and roll bending. Among the close tool forming methods is Guerin, Marform, Maslenikov, radial expanding and extrusion. The following are examples of tools and differences compared to conventional methods and liquids. The advantage of elastomeric tool is a low cost, simplicity and frugality to surface modified products. The disadvantage is a low life, low productivity and the use of large forming forces. Forming using elastomers has application in the prototypes and small series production.
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Modification of Biodegradable Polyurethanes by Biologically Active Substances
Kupka, Vojtěch ; Khunová, Viera (referee) ; Pekař, Miloslav (referee) ; Vojtová, Lucy (advisor)
Předkládaná dizertační práce se zabývá novým způsobem přípravy biodegradabilních polyuretanů (PU) a jejich modifikací biologicky aktivními celulózovými nanokrystaly. Literární rešerše se zaměřuje na bioresorbovatelné PU v tkáňovém inženýrství. Shrnuje příklady těchto PU elastomerů, skafoldů (nosičů buněk) i injektovatelných PU společně se způsoby biodegradace na netoxické produkty. Poslední část je zaměřena na nanocelulózu, která si získala pozornost díky svým pozoruhodným fyzikálním (velký specifický povrch, mechanické vlastnosti) a biologickým (biokompatibilita, biodegradabilita a nízká toxicita) vlastnostem jako materiál pro biomedicínu. V experimentální části byly charakterizovány amfifilní biodegradovatelné polyuretanové filmy (bio-PU) syntetizované bez použití rozpouštědla polyadiční reakcí z hydrofilního poly(ethylenglykolu) (PEG) a hydrofobního poly(e-kaprolaktonu) (PCL) jako makrodiolů společně s hexamethylen diizokyanátem. Připravené bio-PU filmy byly charakterizovány pro různé poměry jak mezi PEG/PCL, tak i mezi NCO/OH reagujícími skupinami (izokyanátový poměr). Bio-PU filmy projevily markantní nárůst mechanických vlastností při hmotnostním poměru PEG/PCL rovnému nebo menšímu než 20/80 díky vzniku krystalických domén PCL. Přítomnost PEGu zvyšovala schopnost bio-PU filmu absorbovat vodu i urychlila jeho hydrolytickou degradaci. Oproti tomu nižší absorpční schopnost a delší čas hydrolytické degradace materiálu způsobil vyšší izokyanátový poměr, a tedy i vyšší síťová hustota. Třetí část práce se zabývá přípravou polyuretanových nanokompozitů unikátní metodou bez použití rozpouštědla za využití bio-PU matrice a celulózových nanokrystalů buď nemodifikovaných, nebo povrchově roubovaných PEGem. Strukturní analýza prokázala, že přítomnost tyčinkovitých nanočástic způsobuje imobilizaci polymerních segmentů, v důsledku čehož se zvýšila tuhost a křehkost materiálu. Nastavením vhodného poměru mezi PEG/PCL, množstvím izokyanátu, či přídavkem modifikovaného nanoplniva může být bio-PU materiál "ušit na míru" s vhodnými mechanickými (houževnatost, tažnost) a fyzikálními (botnání, degradace) vlastnostmi. Díky přípravě bez použití rozpouštědla by mohly být připravené materiály využity v regenerativní medicíně např. jako cévní štěpy.
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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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