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The influence of detergents on time to failure of high density polyethylene by full notch creep test performed in corrosive bath
Kotoučková, Simona ; Tocháček, Jiří (referee) ; Bálková, Radka (advisor)
The thesis deals with the study of the influence of concentration and different types of surfactants (Igepal CO-520, Arkopal N110, Igepal CO-890, sodium dodecyl sulfate, sodium dodecylbenzenesulfonate, dodecyltrimethylammonium bromide and Dehyton PL) on the environmental stress cracking resistance of high-density polyethylene by means of Full Notch Creep Test. Furthermore, the influence of ligamental stress (3,5; 4,0 a 4,5 MPa), pH of the prepared active environment and type of the water used as a solvent for the surfactants on the time to failure was monitored. An accelerating effect was observed at increased concentration, stress and molecular weight. Faster failure was achieved after exposure to ionic types compared to nonionic. The rate of the notch opening was determined. The brittle and ductile behavior during the process of failure was evaluated by microscopic analysis of the morphology of the fracture surfaces. Based on the pH change after the test, the stability of the active environment was evaluated. Deteriorating quality of surfactant solutions was observed. Raman spectroscopy and Fourier transform infrared spectroscopy were used to detect the surfactant on the surface of the test specimen after the test.
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Structure and properties of physically foamed polymer nanocomposites
Kotoučková, Simona ; Ondreáš, František (referee) ; Lepcio, Petr (advisor)
This work deals with physically foamed polymer nanocomposites. The theoretical part of the thesis deals with various possibilities of preparation of polymer foams. Another important problematics on which the theoretical part focuses is the ability to control the spatial organization of nanoparticles in a polymer matrix. For the experimental part, polymethyl methacrylate (PMMA) was used as a model system, and it is assumed that it will be possible to based on the obtained conclusions on research in more complicated systems with a wider practical application potential such as polypropylene impact-copolymer (ICPP). The experimental part focuses on optimalization of the process of preparing nanocomposite foam. The object of optimization is to determine the appropriate saturation time when maximum carbon dioxide saturation is achieved under a given pressure. The effect of nanoparticles on the process of saturation and foaming was analyzed by comparing nanocomposites with the preparation of pure polymer foams. On the prepared foam samples, the shape stability during foaming and the dimensional stability after foaming at elevated temperature were evaluated. The effect of nanoparticles on the resulting structure of porous material was evaluated. This effect was demonstrated by the preparation and evaluation of acquired SEM images of a laminar structure sample containing a composite and a pure polymer layer.
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The influence of detergents on time to failure of high density polyethylene by full notch creep test performed in corrosive bath
Kotoučková, Simona ; Tocháček, Jiří (referee) ; Bálková, Radka (advisor)
The thesis deals with the study of the influence of concentration and different types of surfactants (Igepal CO-520, Arkopal N110, Igepal CO-890, sodium dodecyl sulfate, sodium dodecylbenzenesulfonate, dodecyltrimethylammonium bromide and Dehyton PL) on the environmental stress cracking resistance of high-density polyethylene by means of Full Notch Creep Test. Furthermore, the influence of ligamental stress (3,5; 4,0 a 4,5 MPa), pH of the prepared active environment and type of the water used as a solvent for the surfactants on the time to failure was monitored. An accelerating effect was observed at increased concentration, stress and molecular weight. Faster failure was achieved after exposure to ionic types compared to nonionic. The rate of the notch opening was determined. The brittle and ductile behavior during the process of failure was evaluated by microscopic analysis of the morphology of the fracture surfaces. Based on the pH change after the test, the stability of the active environment was evaluated. Deteriorating quality of surfactant solutions was observed. Raman spectroscopy and Fourier transform infrared spectroscopy were used to detect the surfactant on the surface of the test specimen after the test.
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Structure and properties of physically foamed polymer nanocomposites
Kotoučková, Simona ; Ondreáš, František (referee) ; Lepcio, Petr (advisor)
This work deals with physically foamed polymer nanocomposites. The theoretical part of the thesis deals with various possibilities of preparation of polymer foams. Another important problematics on which the theoretical part focuses is the ability to control the spatial organization of nanoparticles in a polymer matrix. For the experimental part, polymethyl methacrylate (PMMA) was used as a model system, and it is assumed that it will be possible to based on the obtained conclusions on research in more complicated systems with a wider practical application potential such as polypropylene impact-copolymer (ICPP). The experimental part focuses on optimalization of the process of preparing nanocomposite foam. The object of optimization is to determine the appropriate saturation time when maximum carbon dioxide saturation is achieved under a given pressure. The effect of nanoparticles on the process of saturation and foaming was analyzed by comparing nanocomposites with the preparation of pure polymer foams. On the prepared foam samples, the shape stability during foaming and the dimensional stability after foaming at elevated temperature were evaluated. The effect of nanoparticles on the resulting structure of porous material was evaluated. This effect was demonstrated by the preparation and evaluation of acquired SEM images of a laminar structure sample containing a composite and a pure polymer layer.
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