|
|
Adaptability of electrospun nanofibers for bone-tissue engineering
Havlíková, Tereza ; Kaspar, Pavel (referee) ; Papež, Nikola (advisor)
The field of bone tissue engineering focuses on developing biocompatible scaffolds, which can successfully mimic the extracellular matrix of human tissue and provide the growing bone cells with the necessary mechanical support and adequate stimulation for proper growth and proliferation. This bachelor thesis describes the basic principles of tissue engineering with an emphasis on the area of bone tissue regeneration, examines current technological challenges and discusses prospective materials and technologies for the design of a compatible tissue scaffold. Electrospun nanofibers, their characteristic properties and adaptability are discussed in more detail. Based on the theoretical findings from the research, a design of a suitable scaffold created from the selected material for following seeding of bone cells, and the planned production procedures are presented. According to the design, the tissue scaffold is manufactured and a series of fundamental research analyses are conducted on it in terms of its structural integrity, chemical composition, wettability, crystalline phase content and cell adhesion. The results of these analyses inform the conclusion regarding the tissue scaffold’s adaptability for bone tissue engineering.
|
|
|
Recycling technology for plastics components of car batteries
Bartoš, Otakar ; Tocháček, Jiří (referee) ; Melčová, Veronika (advisor)
This paper deals with the recycling of plastics from lithium batteries, more specifically polyvinylidenefluoride and polyethylene. Two samples of different nature were analysed. For the first sample, the presence of polyvinylidene fluoride was expected and the sample was analysed by TGA, DSC and FTIR. It was found to contain a maximum of 3.53 % PVDF contaminated by the solvent NMP, which was used for isolation and failed to evaporate. The remainder of the sample consisted mainly of HDPE and contained other unspecified contaminants in smaller quantities. The second sample in the form of a mixture of films was manually sorted and characterised by FTIR and was found to contain 80% HDPE film and 18 % PP. Subsequently, unsorted, and sorted batches consisting of PE were created and treated by mixing, leaching, both, or none to determine the effect of the treatments on the resulting mechanical properties. After the treatments, the batches were processed by kneading and tested by tensile tests. The results show that the leached batches have a higher tensile modulus, around 1.7 GPa, than the other batches, which is close to the reference material HDPE Liten MB 71, while the mixed batches have a higher purity as determined by SEM/EDS analysis. The treated samples also achieve very high elongation at break. The highest elongation achieved was above 500 %. In addition, blends of the reference material HDPE Liten MB 71 and 10, 20 and 30 wt.% of re-sorted, leached, and mixed PE films were made. The blends were again processed by kneading and subjected to tensile tests. Overall, the properties of the 20 % blend with a modulus of elasticity of 1.74 GPa and stress at yield point of 29.1 MPa, were closest to the reference material and represent a suitable compromise between the amount of added recyclate and the deterioration of mechanical properties.
|
|
|
Energy dispersive X-ray spectroscopy of doped PVDF fibers
Smejkalová, Tereza ; Papež, Nikola (referee) ; Sobola, Dinara (advisor)
Tato diplomová práce zkoumá flexibilní materiál k produkci elektřiny založený na piezoelektrickém polymeru Polyvinylidenfluorid (PVDF). Inkorporací piezoaktivní keramiky lze vlastnosti piezoelektrického polymeru PVDF významně zlepšit a převést na užitečnou elektrickou energii. PVDF byl vytvořen elektrostatickým zvlákňováním do vláken o tloušťce 1,5-0,3 µm a poté studován různými analytickými metodami. Tato práce nabízí popis elektrostatického zvlákňování, přípravu vzorků a teoretický úvod do analytických metod, kterým byly vzorky podrobeny. Morfologie a distribuce nanostrukturované keramiky do polymerní matrice PVDF byla pozorována použitím skenovací elektronové mikroskopie (SEM) a energiově disperzní spektroskopie (EDX). Pro tvorbu fáze a podrobné fázové složení byly vzorky charakterizovány infračervenou spektroskopií s Fourierovou transformací (FTIR). Práce také obsahuje analýzu s použitím Ramanovy spektroskopie, metody používané k identifikaci a porovnání chemických sloučenin. Elektrické vlastnosti byly studovány dielektrickou spektroskopií a je poskytnuta korelace se složením. Jednotlivé komponenty dotovaných vláken jsou charakterizovány a vyhodnocovány v souvislosti s jejich budoucím využitím v senzorech.
|
|
|
Electrospinning of composite fiberous structures for piezoapplications
Schifferová, Zuzana ; Kaštyl, Jaroslav (referee) ; Částková, Klára (advisor)
Polymer and composite polymer-ceramic nanofibers were prepared by electrospinning process. Solution of 20 wt.% polyvinylidene fluoride (PVDF) in a mixture of dimethyl sulfoxide (DMSO) and acetone in the ratio of 7:3 was chosen as the most suitable precursor. When preparing composite nanofibers, 20 wt.% of barium calcium zirconate titanate (BCZT) or barium titanate (BT) nanoparticles was added to this PVDF solution. Given parameters were defined as the most suitable for the process of electrospinning: voltage of 50 kV, feeding rate of 30 l/min, distance between emitter and collector of 20 cm and needle diameter of 17 G. The effect of polymer molecular weight and the rotation speed of collector was also studied. Various properties of prepared samples were studied: morphology and fiber diameter, phase composition with the use of x-ray diffraction and Fourier transform infrared spectroscopy and also chosen electrical properties. Lower fiber diameters appeared with lower polymer molecular weight and higher rotation speed of the collector. These parameters resulted in higher percentage of the piezoelectric phase as well. The smallest achieved fiber diameter was around 300 nm, the highest percentage of phase was 92 % and the highest piezoelectric constant had a value of 16 pC/N. Composite fibers filled with BT particles showed better properties that the ones filled with BCZT particles.
|
|
|
Energy dispersive X-ray spectroscopy of doped PVDF fibers
Smejkalová, Tereza ; Papež, Nikola (referee) ; Sobola, Dinara (advisor)
Tato diplomová práce zkoumá flexibilní materiál k produkci elektřiny založený na piezoelektrickém polymeru Polyvinylidenfluorid (PVDF). Inkorporací piezoaktivní keramiky lze vlastnosti piezoelektrického polymeru PVDF významně zlepšit a převést na užitečnou elektrickou energii. PVDF byl vytvořen elektrostatickým zvlákňováním do vláken o tloušťce 1,5-0,3 µm a poté studován různými analytickými metodami. Tato práce nabízí popis elektrostatického zvlákňování, přípravu vzorků a teoretický úvod do analytických metod, kterým byly vzorky podrobeny. Morfologie a distribuce nanostrukturované keramiky do polymerní matrice PVDF byla pozorována použitím skenovací elektronové mikroskopie (SEM) a energiově disperzní spektroskopie (EDX). Pro tvorbu fáze a podrobné fázové složení byly vzorky charakterizovány infračervenou spektroskopií s Fourierovou transformací (FTIR). Práce také obsahuje analýzu s použitím Ramanovy spektroskopie, metody používané k identifikaci a porovnání chemických sloučenin. Elektrické vlastnosti byly studovány dielektrickou spektroskopií a je poskytnuta korelace se složením. Jednotlivé komponenty dotovaných vláken jsou charakterizovány a vyhodnocovány v souvislosti s jejich budoucím využitím v senzorech.
|
|
|
Electrospinning of composite fiberous structures for piezoapplications
Schifferová, Zuzana ; Kaštyl, Jaroslav (referee) ; Částková, Klára (advisor)
Polymer and composite polymer-ceramic nanofibers were prepared by electrospinning process. Solution of 20 wt.% polyvinylidene fluoride (PVDF) in a mixture of dimethyl sulfoxide (DMSO) and acetone in the ratio of 7:3 was chosen as the most suitable precursor. When preparing composite nanofibers, 20 wt.% of barium calcium zirconate titanate (BCZT) or barium titanate (BT) nanoparticles was added to this PVDF solution. Given parameters were defined as the most suitable for the process of electrospinning: voltage of 50 kV, feeding rate of 30 l/min, distance between emitter and collector of 20 cm and needle diameter of 17 G. The effect of polymer molecular weight and the rotation speed of collector was also studied. Various properties of prepared samples were studied: morphology and fiber diameter, phase composition with the use of x-ray diffraction and Fourier transform infrared spectroscopy and also chosen electrical properties. Lower fiber diameters appeared with lower polymer molecular weight and higher rotation speed of the collector. These parameters resulted in higher percentage of the piezoelectric phase as well. The smallest achieved fiber diameter was around 300 nm, the highest percentage of phase was 92 % and the highest piezoelectric constant had a value of 16 pC/N. Composite fibers filled with BT particles showed better properties that the ones filled with BCZT particles.
|
guest ::
