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Short fiber reinforced composite for dental use: preparation and characterization
Henkrichová, Jana ; Přikryl, Radek (oponent) ; Poláček, Petr (vedoucí práce)
This diploma thesis studies short fiber reinforced composites for dental applications. Barium particulate filler, nanosilica and short glass and polyvinylalcohol fibers were added to the matrix consisting of four dimethacrylate types of monomers. The effect on material properties was observed. For characterization of different types of composite materials following methods were used: thermogravimetric analysis (TGA), dynamic mechanical analysis (DMA), three point bending test for notched and un-notched samples and scanning electron microscopy (SEM). Viscoelastic properties, modulus of elasticity and strength, critical values of stress intensity factor and strain energy release rate and polymerization shrinkage of composite materials were determined. It is possible to improve these properties of composite materials by adding short fibres to particulate reinforced composite. To make this modification more efficient, it is necessary to change surface treatment of fibres and preparation method of short fiber reinforced composites. Viscosity of material has raised after adding short fibers and processing of these types of dental material in dental laboratory is considered difficult to provide.
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Pevnost v ohybu a hydrolytická stabilita FRC/PFC dentálního bi-materiálu
Dombková, Julie ; Trautmann, Radoslav (oponent) ; Poláček, Petr (vedoucí práce)
Tato bakalářská práce se zabývá pevností v ohybu FRC/PFC dentálních bi-materiálů a do jaké míry jsou schopny odolávat hydrolytické degradaci. Vzorky ve tvaru trámečku byly zatěžovány ve tříbodém ohybu. Pevnost a modul pružnosti byly měřeny za použití univerzálního testovacího stroje Zwick Z0100. Skenovací elektronový mikroskop (SEM) byl použit pro pozorování porušených míst. Ze získaných výsledků vyplývá, že mechanické vlastnosti jsou ovlivněny kvalitou smáčení vláknového kompozitu, prostorovým uspořádáním výztuže, absorpcí vody do použitých materiálů a adhezí mezi matricí a výztuží.
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Crosslinking of thermosensitive functionalized copolymers by blue light
Křivánková, Nikola ; Michlovská, Lenka (oponent) ; Vojtová, Lucy (vedoucí práce)
The aim of this thesis was to prepare a hydrogel with a hybrid network of only one type of biodegradable copolymer. The new degradable hydrogel, containing both physical interactions (arising at physiological temperature of 37 °C) and chemical bonds initiated by blue light could be used as a resorbable wound dressing or as an injectable carrier with a gradual and well controlled drug release. Thermosensitive PLGA–PEG–PLGA copolymer synthesized by living ring-opening polymerization was subsequently functionalized with itaconic anhydride to form ITA/PLGA–PEG–PLGA/ITA light-sensitive and temperature-sensitive macromonomer. At 37 °C, the copolymer forms a micellar network due to hydrophobic interactions. Itaconic acid double bonds, which are attached to the ends of the copolymer chain, allow photochemical crosslinking of micelles with a view to increase the hydrolytic stability of novel hydrogel. The synthesized copolymers were characterized by GPC and 1H NMR methods. The formation of a physical network at physiological temperature was confirmed by rheological analysis. The physically crosslinked ITA/PLGA–PEG–PLGA/ITA hydrogel was then irradiated with blue light (430 – 490 nm) in the presence of a water soluble biocompatible photoinitiator LiTPO and chemically characterized by ATR-FTIR. The resulting hydrogel was transparent, flexible, absorbed up to 1176 % water, and was stable for 20 days in saline at 37 °C. The ITA/PLGA–PEG–PLGA/ITA hydrogel with hybrid network was also prepared in the presence of a crosslinker PEGDA, that significantly reduced the time required for crosslinking the hydrogel, but further analyses are needed to more fully understand the principles of the novel hydrogel types.
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Crosslinking of thermosensitive functionalized copolymers by blue light
Křivánková, Nikola ; Michlovská, Lenka (oponent) ; Vojtová, Lucy (vedoucí práce)
The aim of this thesis was to prepare a hydrogel with a hybrid network of only one type of biodegradable copolymer. The new degradable hydrogel, containing both physical interactions (arising at physiological temperature of 37 °C) and chemical bonds initiated by blue light could be used as a resorbable wound dressing or as an injectable carrier with a gradual and well controlled drug release. Thermosensitive PLGA–PEG–PLGA copolymer synthesized by living ring-opening polymerization was subsequently functionalized with itaconic anhydride to form ITA/PLGA–PEG–PLGA/ITA light-sensitive and temperature-sensitive macromonomer. At 37 °C, the copolymer forms a micellar network due to hydrophobic interactions. Itaconic acid double bonds, which are attached to the ends of the copolymer chain, allow photochemical crosslinking of micelles with a view to increase the hydrolytic stability of novel hydrogel. The synthesized copolymers were characterized by GPC and 1H NMR methods. The formation of a physical network at physiological temperature was confirmed by rheological analysis. The physically crosslinked ITA/PLGA–PEG–PLGA/ITA hydrogel was then irradiated with blue light (430 – 490 nm) in the presence of a water soluble biocompatible photoinitiator LiTPO and chemically characterized by ATR-FTIR. The resulting hydrogel was transparent, flexible, absorbed up to 1176 % water, and was stable for 20 days in saline at 37 °C. The ITA/PLGA–PEG–PLGA/ITA hydrogel with hybrid network was also prepared in the presence of a crosslinker PEGDA, that significantly reduced the time required for crosslinking the hydrogel, but further analyses are needed to more fully understand the principles of the novel hydrogel types.
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Short fiber reinforced composite for dental use: preparation and characterization
Henkrichová, Jana ; Přikryl, Radek (oponent) ; Poláček, Petr (vedoucí práce)
This diploma thesis studies short fiber reinforced composites for dental applications. Barium particulate filler, nanosilica and short glass and polyvinylalcohol fibers were added to the matrix consisting of four dimethacrylate types of monomers. The effect on material properties was observed. For characterization of different types of composite materials following methods were used: thermogravimetric analysis (TGA), dynamic mechanical analysis (DMA), three point bending test for notched and un-notched samples and scanning electron microscopy (SEM). Viscoelastic properties, modulus of elasticity and strength, critical values of stress intensity factor and strain energy release rate and polymerization shrinkage of composite materials were determined. It is possible to improve these properties of composite materials by adding short fibres to particulate reinforced composite. To make this modification more efficient, it is necessary to change surface treatment of fibres and preparation method of short fiber reinforced composites. Viscosity of material has raised after adding short fibers and processing of these types of dental material in dental laboratory is considered difficult to provide.
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Pevnost v ohybu a hydrolytická stabilita FRC/PFC dentálního bi-materiálu
Dombková, Julie ; Trautmann, Radoslav (oponent) ; Poláček, Petr (vedoucí práce)
Tato bakalářská práce se zabývá pevností v ohybu FRC/PFC dentálních bi-materiálů a do jaké míry jsou schopny odolávat hydrolytické degradaci. Vzorky ve tvaru trámečku byly zatěžovány ve tříbodém ohybu. Pevnost a modul pružnosti byly měřeny za použití univerzálního testovacího stroje Zwick Z0100. Skenovací elektronový mikroskop (SEM) byl použit pro pozorování porušených míst. Ze získaných výsledků vyplývá, že mechanické vlastnosti jsou ovlivněny kvalitou smáčení vláknového kompozitu, prostorovým uspořádáním výztuže, absorpcí vody do použitých materiálů a adhezí mezi matricí a výztuží.
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