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Softening of poly(3-hydroxybutyrate)
Brňák, Matúš ; Petruš, Josef (referee) ; Kučera, František (advisor)
The bachelor thesis deals with the inluence of PHB softening, of selected types of plasticizers. The effect of the plasticizers are compared between themselves with regard to their properties and structure. The theoretical part summarizes the knowledge about softening polymers and characterized different types of plasticizers. The experimental part deals with PHB softening in the solution and in the melt. The plasticizers ATBC, TBC, ATEC, TEC, TOTM, PVAc and butylglycolate dilution containing 30 wt % were added to the PHB previously dissolved in chloroform. In the case of softening in the melt, a polymer paste was prepared, containing 70 wt % of plasticizers and 30 wt % of PVAc. The mixture was plasticized in a mixer, wherein time and temperature of the gelatinization were determined experimentally. Thermal degradation of preprared samples were specified by TGA. Values of Tg, Tm and Xc, was determined by DSC analysis. The samples plasticized in the melt were determined by the hardness of the material according to the Shore A scale and the Vickers scale.
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Development and characterization of hydrogel carriers for modern agricultural applications
Mai, Thuy Ha ; Kalina, Michal (referee) ; Sedláček, Petr (advisor)
The bachelor thesis is focused on characterization of hydrogel carriers and their application in agriculture. Entrapment of active phase within the hydrogel matrix would allow release of its content in controlled rate. The theoretical part describes encapsulation techniques and suitable biocompatible materials involved in encapsulation. For the experimental part, the release of soil bacteria Cupriavidus necator H16 from alginate matrix was examined. The focus was on the release rate of bacteria via diffusion and later, on the release rate of bacteria encouraged by chemical or enzymatic reagents. Further modification of carrier was suggested by adding hydrophobic barrier composed of polyhydroxybutyrate (PHB). The modified alginate beads seemed to be more resistant toward enzymatic or chemical agents, thus the process of the release was to some extent suppressed. This fact might suggest PHB as a possible vessel for optimization of controlled release system of hydrogel carriers.
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Development and characterization of hydrogel carriers for modern agricultural applications
Mai, Thuy Ha ; Kalina, Michal (referee) ; Sedláček, Petr (advisor)
The bachelor thesis is focused on characterization of hydrogel carriers and their application in agriculture. Entrapment of active phase within the hydrogel matrix would allow release of its content in controlled rate. The theoretical part describes encapsulation techniques and suitable biocompatible materials involved in encapsulation. For the experimental part, the release of soil bacteria Cupriavidus necator H16 from alginate matrix was examined. The focus was on the release rate of bacteria via diffusion and later, on the release rate of bacteria encouraged by chemical or enzymatic reagents. Further modification of carrier was suggested by adding hydrophobic barrier composed of polyhydroxybutyrate (PHB). The modified alginate beads seemed to be more resistant toward enzymatic or chemical agents, thus the process of the release was to some extent suppressed. This fact might suggest PHB as a possible vessel for optimization of controlled release system of hydrogel carriers.
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Softening of poly(3-hydroxybutyrate)
Brňák, Matúš ; Petruš, Josef (referee) ; Kučera, František (advisor)
The bachelor thesis deals with the inluence of PHB softening, of selected types of plasticizers. The effect of the plasticizers are compared between themselves with regard to their properties and structure. The theoretical part summarizes the knowledge about softening polymers and characterized different types of plasticizers. The experimental part deals with PHB softening in the solution and in the melt. The plasticizers ATBC, TBC, ATEC, TEC, TOTM, PVAc and butylglycolate dilution containing 30 wt % were added to the PHB previously dissolved in chloroform. In the case of softening in the melt, a polymer paste was prepared, containing 70 wt % of plasticizers and 30 wt % of PVAc. The mixture was plasticized in a mixer, wherein time and temperature of the gelatinization were determined experimentally. Thermal degradation of preprared samples were specified by TGA. Values of Tg, Tm and Xc, was determined by DSC analysis. The samples plasticized in the melt were determined by the hardness of the material according to the Shore A scale and the Vickers scale.
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