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Use of ionic liquids for preparation of epoxy materials
Rebei, Marwa ; Beneš, Hynek (advisor) ; Machotová, Jana (referee) ; Polášková, Martina (referee)
Epoxy resins represent an important category of thermosets widely as coatings, electronic encapsulants, matrices for composites, etc., due to their beneficial properties, such as strong adhesion, high chemical and electrical resistance, and good processability. However, their curing reactions present some limitations, such as using catalysts (for example, organometallics, complexes and MOFs) which are active at high reaction temperatures. In most cases, these catalysts are toxic and require organic solvents. Consequently, alternative non-toxic catalysts/initiators that can promote well-controlled fast curing under mild conditions have been explored while maintaining sufficient thermomechanical properties of the formed epoxy networks. In this thesis, three different epoxy ring opening reactions induced by various imidazolium ionic liquids (ILs) were studied. The first subsection (4.1) discusses the step-growth epoxy-dicarboxylic acid polymerization in an imidazolium IL medium conducted under mild conditions (T = 80-120 řC). The IL was shown to act as both a solvent and an initiator/catalyst for the reaction. In addition, IL-anions (chloride, bis(trifluoromethylsulfonyl) imide, or methanesulfonate) strongly affect the progress of the reaction. It was found that the Cl- anion is the most effective...
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Preparation and characterization of epoxy potting resins modified with nanoparticles
Lednický, Jiří ; Polsterová, Helena (referee) ; Chladil, Ladislav (advisor)
This bachelor's thesis focuses on nanocomposites composed of an organic matrix in the form of epoxy resin and TiO2 filler in the anatase crystallographic structure with dimensions in the order of tens of nanometers. The work is aimed at understanding the issue of nanocomposites, summarizing the results of other studies, and especially at the production and characterization of samples with nanoparticles dispersed using a planetary mill. Furthermore, the effect of the used nanoparticles and dispersion in the planetary mill on the dielectric properties of pure epoxy resin was analyzed.
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Production of composite materials using vacuum infusion
Ciran, Adam ; Gregor, Lukáš (referee) ; Zouhar, Jan (advisor)
The theoretical part of the bachelor thesis deals with the definition of composite material, then the division of the most used fabric reinforcements and matrices, with a focus on reinforcements made of glass and carbon fiber and flax fiber. It then discusses vacuum infusion techniques, their description and applications. In the practical part, emphasis is placed on the fabrication of specimens using vacuum infusion technology of carbon fiber, glass fiber and flax using an epoxy matrix. The last part is the evaluation of the fabricated samples.
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Production technology for a vacuum mold
Ponka, Ondřej ; Bartoš, Tomáš (referee) ; Zemčík, Oskar (advisor)
The master thesis deals with the design and production of the mold for vacuum forming. Specifically, how the existing and new mold materials affect their design and, consequently, their production technology. The thesis contains a brief description of the principle of vacuum molding. Technological and design principles of designing molds. Furthermore, the realization of the solution variants and the simulation of their production. The solved variants are subsequently evaluated from a technical and economic point of view.
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Development of high polymer grout system
Ručková, Kateřina ; Seidlová, Michaela (referee) ; Drochytka, Rostislav (advisor)
Bachelor thesis is focused on polymer grout, designed for heavy engineering operations and energy industry. The aim of the thesis is to define the requirements for use of polymer grout and also evaluation of testing procedures and legislative regulations on properties of these materials. Based on theoretical knowledge gained from literature will be designed HighTech polymer grout using secondary input materials.
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Technology of pouring LED strips with epoxy materials
Rudy, Veronika ; Krejčí, Miroslav (referee) ; Píška, Miroslav (advisor)
The thesis deals with the pouring of epoxy materials over LED strips. The research part contains an introduction to photometry and summarizes the types of potting compounds along with their characteristics. The practical part delves into the effect different amount of pigment has on the photometric properties. This is assessed based on verified measurements performed with the help of a goniophotometer on samples with different amounts of pigment, which were created using an integration sphere. Furthermore, a brightness analysis and a long-term outdoor test were performed.
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Electrical properties analysis of epoxy resins with various fillers
Horák, Luděk ; Kazelle, Jiří (referee) ; Frk, Martin (advisor)
Presented bachelor thesis is focused on studying electroinsulating epoxy resin-based sealings. It describes the chemical composition, production, properties and measuring methods of basic electric quantities of these materials. This work also embodies a preparation of composite epoxy resin samples with different kinds of micro-ground siliceous sand as a filling. The samples given are measured on the temperature dependency of relative permitivity, dissipation factor and inner resistivity.
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Study of electric properties of nanocomposit material
Ovsík, Jiří ; Rozsívalová, Zdenka (referee) ; Polsterová, Helena (advisor)
This work deals with the electrical properties of nanocomposite materials. Samples for the experiment are made of epoxy resin as matrix and titanium dioxide TiO2 as nanofillers in varying percentage performance. Measurements are temperature dependent components of the permittivity, dissipation factor and resistivity. Furthermore, the internal resistivity is observed with regard to the percentage performance of a sample of nanoparticles.
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Epoxy resins exposure under severe climatic conditions
Hanačík, Radim ; Rozsívalová, Zdenka (referee) ; Frk, Martin (advisor)
This thesis describes the effects of climatic factors, particularly humidity and temperature on the properties of macromolecular substances, but also others, such as UV radiation, wind, water and oxygen. Furthermore, we introduce the definition and distribution of macromolecular substances. The next section describes the basic properties of dielectric materials. Much of the text is devoted to the description, production, curing, properties and utilization of epoxy resins. The last part deals with climate factors in general terms.
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Stabilizing epoxide systems in surface protective varnishes
Švardala, Daniel ; Tocháček, Jiří (referee) ; Petruš, Josef (advisor)
The diploma thesis describes the influence of humid conditions on the curing of epoxy resins by multifunctional amines. The aim of the experimental part was the identification of degradation products and their quantification, as well as the determination of the influence of humid conditions on the degree of hardening, modulus of elasticity, and flexural strength. Another goal was to optimize the formulation of the reactive mixture for the preparation of epoxy resin with lower susceptibility to carbamate bloom. The degradation products were evaluated by determining the mechanical properties by bending test according to the standard ČSN EN 179-1. The degree of hardening was monitored through temperature modulated differential scanning calorimetry (TMDSC). Degradation products were identified by Fourier transform infrared spectroscopy (FTIR) and quantified by UV-VIS spectroscopy. The morphology of the surface layer was monitored by confocal laser scanning microscopy (CLSM). The dependence of the relative humidity of the environment on the curing process of the epoxy resin and its resulting mechanical properties was determined. Based on the analyzes, a modification of the formulation for the suppression of spurious carbamate during the curing of the epoxy matrix was designed and experimentally verified.
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