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Cellular polymer nanocomposites
Zárybnická, Klára ; Crosby, Alfred (oponent) ; Lehocký,, Marián (oponent) ; Jančář, Josef (vedoucí práce)
This dissertation thesis deals with the preparation and characterization of polymer nanocomposite foams with a focus on means to control their structure at multiple length scales and application in 3D printing in their fabrication. The aim of this work is to investigate polymer nanocomposite with hierarchical structure – from the nano-, through the micro to macro scale. The structural properties of polymer nanocomposites prepared from glassy polymers by the solvent-casting method were investigated in the first part of the work. It has been shown that the difference in the solubility parameters of the polymer and the solvent plays a crucial role. This finding has been verified for systems containing various nanoparticles, polymers, and solvents. With the knowledge of the general principles controlling the structure of nanocomposites, impact polystyrene filled with nanosilica was investigated in greater detail. These nanocomposites were used for the preparation of nanocomposite foams. The porous structure was achieved using a thermal chemical blowing agent azodicarbonamide. The filaments were extruded and the material was processed by 3D printing into the required shapes and foamed. The result was a hierarchical system with the organization of the structure from nano (organization of nanoparticles), through micro (two-component polymer blend structure and foam structure) to macro scale (foam structure and 3D printed design). The effect of nanoparticles on the structure and the thermal and mechanical properties of polymeric foams were observed. The nanoparticles operate as a nucleating agent in the formation of the foam. Pores are easily formed on their surface so that with the content of nanoparticles in the system smaller pores have been formed, which helped to make the foam fine and homogeneous. The presence of nanoparticles changed the surface energy of the blowing agent grains, thanks to which it decomposed at lower temperatures and foaming was even faster. At the same time, nanoparticles have the potential to reinforce foam walls and thus improve mechanical properties. 3D printing is a popular and widespread technique, due to its simplicity it is in many laboratories and test institutions, therefore the demand for filaments with special properties is growing. The material developed in this dissertation is essentially a finished and characterized product that could contribute to the satisfaction of this claim.
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Cellular polymer nanocomposites
Zárybnická, Klára ; Crosby, Alfred (oponent) ; Lehocký,, Marián (oponent) ; Jančář, Josef (vedoucí práce)
This dissertation thesis deals with the preparation and characterization of polymer nanocomposite foams with a focus on means to control their structure at multiple length scales and application in 3D printing in their fabrication. The aim of this work is to investigate polymer nanocomposite with hierarchical structure – from the nano-, through the micro to macro scale. The structural properties of polymer nanocomposites prepared from glassy polymers by the solvent-casting method were investigated in the first part of the work. It has been shown that the difference in the solubility parameters of the polymer and the solvent plays a crucial role. This finding has been verified for systems containing various nanoparticles, polymers, and solvents. With the knowledge of the general principles controlling the structure of nanocomposites, impact polystyrene filled with nanosilica was investigated in greater detail. These nanocomposites were used for the preparation of nanocomposite foams. The porous structure was achieved using a thermal chemical blowing agent azodicarbonamide. The filaments were extruded and the material was processed by 3D printing into the required shapes and foamed. The result was a hierarchical system with the organization of the structure from nano (organization of nanoparticles), through micro (two-component polymer blend structure and foam structure) to macro scale (foam structure and 3D printed design). The effect of nanoparticles on the structure and the thermal and mechanical properties of polymeric foams were observed. The nanoparticles operate as a nucleating agent in the formation of the foam. Pores are easily formed on their surface so that with the content of nanoparticles in the system smaller pores have been formed, which helped to make the foam fine and homogeneous. The presence of nanoparticles changed the surface energy of the blowing agent grains, thanks to which it decomposed at lower temperatures and foaming was even faster. At the same time, nanoparticles have the potential to reinforce foam walls and thus improve mechanical properties. 3D printing is a popular and widespread technique, due to its simplicity it is in many laboratories and test institutions, therefore the demand for filaments with special properties is growing. The material developed in this dissertation is essentially a finished and characterized product that could contribute to the satisfaction of this claim.
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