|
|
Increases in water resistance of MDF composites
Másilko, Jiří ; Zmrzlý, Martin (referee) ; Šoukal, František (advisor)
The subject of the diploma thesis is the study of moisture resistance of macrodefect-free (MDF) cements based on calcium-aluminate cement and polyvinylalcohol used as polymer. MDF cements are perspective materials providing unique properties relative to traditional cement pastes with great potential to incoming constructional utilization. But it is known that MDF cements exhibit sensitivity to water, with swelling and reduction of strength. Therefore the work is aimed in monitoring of an organic polymer effect on the moisture resistance of MDF materials and phase changes. Aluminate cement (SECAR 51) and polyvinylalcohol/acetate copolymer have been used for the MDF cement preparation. The moisture resistance of model MDF cement samples was investigated at two different curing conditions: in the moist atmosphere and immersed in water. The influence of composition and individual curing on the properties of model MDF cement samples was observed. The characterization of MDF samples was based especially on test of flexural strength, FT-IR, EDAX and optical microscopy analyses.
|
|
|
Energy dispersive X-ray spectroscopy of doped PVDF fibers
Smejkalová, Tereza ; Papež, Nikola (referee) ; Sobola, Dinara (advisor)
Tato diplomová práce zkoumá flexibilní materiál k produkci elektřiny založený na piezoelektrickém polymeru Polyvinylidenfluorid (PVDF). Inkorporací piezoaktivní keramiky lze vlastnosti piezoelektrického polymeru PVDF významně zlepšit a převést na užitečnou elektrickou energii. PVDF byl vytvořen elektrostatickým zvlákňováním do vláken o tloušťce 1,5-0,3 µm a poté studován různými analytickými metodami. Tato práce nabízí popis elektrostatického zvlákňování, přípravu vzorků a teoretický úvod do analytických metod, kterým byly vzorky podrobeny. Morfologie a distribuce nanostrukturované keramiky do polymerní matrice PVDF byla pozorována použitím skenovací elektronové mikroskopie (SEM) a energiově disperzní spektroskopie (EDX). Pro tvorbu fáze a podrobné fázové složení byly vzorky charakterizovány infračervenou spektroskopií s Fourierovou transformací (FTIR). Práce také obsahuje analýzu s použitím Ramanovy spektroskopie, metody používané k identifikaci a porovnání chemických sloučenin. Elektrické vlastnosti byly studovány dielektrickou spektroskopií a je poskytnuta korelace se složením. Jednotlivé komponenty dotovaných vláken jsou charakterizovány a vyhodnocovány v souvislosti s jejich budoucím využitím v senzorech.
|
|
|
Polymer protective systems for concrete floors
Novotná, Adéla ; Vyhnánek, Miroslav (referee) ; Petránek, Vít (advisor)
The thesis is addressing the testing of protective polymer layers, which are used mainly for industrial floors. A summary table of standards is presented, dividing the test carried out on the binders, fillers, fresh mixture and polymerized material. Non standardize tests are described in detail in a very similar way as it is performed by the Institute of Technology of Building Materials and Components. The second part of my thesis is devoted to testing of the reference material and material filled with raw substances. Based on recommendations of Lena Chemical Company, filler – ground windscreen glass will be used. On this type of mixture selected set of tests needed for construction and technical certificates was performed.
|
|
|
Production technology of plastic switch frame
Seidlman, František ; Kebrle, Ondřej (referee) ; Kandus, Bohumil (advisor)
This Diploma contains theme of injection of plastics. The theoretical section is focused on polymeric materials, their dividing and characteristics. From technologies for processing plastic is chosen injection of plastic, suitable for production technology of plastic switch frame. After that follows design of injection mould including calculation and designing drawing underlaid technical economic evaluation.
|
|
| |
|
|
Review of manufacturing methods for structural parts from short-fiber polymeric composites and methods for improving their mechanical properties
Starčuk, Zenon ; Löffelmann, František (referee) ; Symonov, Volodymyr (advisor)
Krátkovlákenné polymerní kompozity jsou jednodušší na výrobu než dlouhovlákenné kompozity, ale za cenu horších mechanických vlastností (t.j. pevnosti v tahu a modulu pružnosti). Existuje mnoho způsobů výroby krátkovlákenných polymerních kompozitů. Většina metod nevyžaduje lidskou práci a metody výroby kompozitů a polymerů jsou stejné, nebo alespoň velice podobné. To vede k tomu, že krátkovlákenné kompozity jsou poměrně levné. Mechanické vlastnosti krátkovlákenných kompozitů mohou být zlepšeny zarovnáním vláken v matrici. Během posledních 60 let byla vyvinuta celá řada metod zarovnávání vláken, ale většina z nich se ukázala jako nepoužitelná pro komerční využití. Některé novější metody ovšem dosáhly výborných výsledků, a těm je v práci věnováno více prostoru. V práci je i návrh dvou nových metod k zarovnávání vláken, první pomocí elektrického proudu a druhé pomocí kombinace statického a oscilujícího magnetického pole.
|
|
|
Modern methods of polymers characterisation
Ropek, Lukáš ; Klakurková, Lenka (referee) ; Hutařová, Simona (advisor)
The bachelor thesis consists of an overview of modern methods of polymers testing. The first part deals with historical development, various types and synthesis of polymers. Further work is focused on the structure of polymers, a description of modern sample preparation methods and methods of study the polymers structure. Next, the mechanical properties of polymers and methods of testing the mechanical properties are discussed. Finally, the work is focused on material resistance testing of polymer pipes used in current practice.
|
|
|
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.
|
|
|
Design of manufacturing technology for plastic hung
Popelka, Jan ; Kebrle, Ondřej (referee) ; Kandus, Bohumil (advisor)
The aim of my graduation theses is to work up the literature search of polymer processing. To give a short summary of their structure, characteristic and fabrication technique. Then to make a structural design of injection mold for producing the scheduled aim and motivate this design with requisite calculation for construction of the tool, a choice of injection machine and rundown of injection cycle. At the end of my work is this aim economically reviewed and compared with alternative form of structural design.
|
|
|
Development of multilayer polymer floor systems
Tesař, Filip ; Vyhnánek, Miroslav (referee) ; Petránek, Vít (advisor)
Multilayer polymer flooring systems belongs to widespread materials for industrial constructions and also for public constructions. These are mostly two-components polymeric materials based on epoxy. The main aim of my thesis is to make list of requirements for multilayer polymer flooring system and utilization of waste materials as fillers in polymer epoxy. Then use this knowledge for development of multilayer polymer flooring system and propose the new recipe and primary test´s for this material.
|
guest ::
