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Effect of chemical structure of plasticizer on material properties based on polyhydroxybutyrate
Stehnová, Ivana ; Alexy, Pavol (referee) ; Přikryl, Radek (advisor)
This master’s thesis deals with plasticization of poly(3-hydroxybutyrate), polylactid acid and their blend. It explores effect of chemical structure of plasticizer on mechanical properties of this polymer blend and on its diffusion from the polymer blend. Syntheses of plasticizers based on oligomeric polyadipates, citrates, lactate and esters of 2 ethylhexanoic acid with poly(ethyleneglycol) were carried out. Molecular weight distribution of synthesized plasticizers was determined using gel permeation chromatography. Poly(3-hydroxybutyrate), polylactid acid and their blend were plasticized with synthesized and commercial plasticizers. From commercial, chosed plasticizers were based on citrates and ester of 2-ethylhexanoic acid with poly(ethyleneglycol). Thermal stability of selected commercial plasticizers in polylactid acid was studied using thermogravimetry. Diffusion of plasticizers from poly(3-hydroxybutyrate), polylactid acid and their blend during exposure to 110 °C was also investigated. Mechanical properties of prepared blends were tested by tensile test. Almost all used plasticizers showed positive softening effect in blend. The highest elongation at break was detected for the blend with commercial acetyltributylcitrate, where elongation at break reached 328 % relative to 21 % for neat non-plasticized blend.
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The heat transfer medium in heating systems
Michalíčková, Iveta ; Blasinski, Petr (referee) ; Počinková, Marcela (advisor)
Theme of diploma thesis is the heat transfer medium in heating systems. The thesis is departed to three parts. In the first part, there is a theoretical solution of heat transfer mediums. In the second part, there is a calculation solution of the project. Project solves heating of the apartment building. There are two variants of heating source and water treatment. Those variants are compared. The last part is experimental part. Theme of the experiment is quality of heating water in heating systems.
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Biodegradable thermoplastics from renewable resources
Březinová, Štěpánka ; Kučera, František (referee) ; Petruš, Josef (advisor)
The theoretical part of diploma thesis summarizes the state of the art in the field of biodegradable thermoplastic materials, emphasizing polymeric materials made from renewable sources and the possibilities for their processing and for the modification of their useful properties. The experimental part of the thesis is focused on the preparation and characterization of biodegradable polymer blends based on thermoplastic starch (TPS) and poly(butylene adipate-co-terephthalate) (ECX). A suitable type of TPS was selected according to the rheological behavior of the melt for blending with ECX via extrusion technology. The degree of compatibility between TPS and ECX was evaluated by infrared spectroscopy (FTIR-ATR) and by examining the morphology of TPS/ECX blends using scanning electron microscopy (SEM). Affecting the mechanical properties, rheological behavior, and wettability of the prepared TPS/ECX was verified by testing the mechanical properties under tensile stress, determining the melt flow index (MFI), employing the oscillatory rheological test, and determining the maximum wettability. The experimentally obtained results show the possibility of optimizing the mechanical and rheological properties of TPS by blending with ECX. In terms of biodegradability, blends with a majority TPS content can be assumed to be more advantageous.
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Effect of chemical structure of plasticizer on material properties based on polyhydroxybutyrate
Stehnová, Ivana ; Alexy, Pavol (referee) ; Přikryl, Radek (advisor)
This master’s thesis deals with plasticization of poly(3-hydroxybutyrate), polylactid acid and their blend. It explores effect of chemical structure of plasticizer on mechanical properties of this polymer blend and on its diffusion from the polymer blend. Syntheses of plasticizers based on oligomeric polyadipates, citrates, lactate and esters of 2 ethylhexanoic acid with poly(ethyleneglycol) were carried out. Molecular weight distribution of synthesized plasticizers was determined using gel permeation chromatography. Poly(3-hydroxybutyrate), polylactid acid and their blend were plasticized with synthesized and commercial plasticizers. From commercial, chosed plasticizers were based on citrates and ester of 2-ethylhexanoic acid with poly(ethyleneglycol). Thermal stability of selected commercial plasticizers in polylactid acid was studied using thermogravimetry. Diffusion of plasticizers from poly(3-hydroxybutyrate), polylactid acid and their blend during exposure to 110 °C was also investigated. Mechanical properties of prepared blends were tested by tensile test. Almost all used plasticizers showed positive softening effect in blend. The highest elongation at break was detected for the blend with commercial acetyltributylcitrate, where elongation at break reached 328 % relative to 21 % for neat non-plasticized blend.
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The heat transfer medium in heating systems
Michalíčková, Iveta ; Blasinski, Petr (referee) ; Počinková, Marcela (advisor)
Theme of diploma thesis is the heat transfer medium in heating systems. The thesis is departed to three parts. In the first part, there is a theoretical solution of heat transfer mediums. In the second part, there is a calculation solution of the project. Project solves heating of the apartment building. There are two variants of heating source and water treatment. Those variants are compared. The last part is experimental part. Theme of the experiment is quality of heating water in heating systems.
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