|
|
Synthesis of Lanthanidocene Based Compounds
Pospíšek, Marek ; Zmrzlý, Martin (referee) ; Richtera, Lukáš (advisor)
The aim of this bachelor thesis is to summarize the issues of the polymerization catalytic systems based on lanthanidocene complexes. These complexes are subsequently divided by the structure into four basic groups. One part of this work deals with an overview of the most interesting results of the catalytic systems, which are then analyzed and assessed either in its entirety or point of view of catalytic activity, living mechanism of polymerisation and stereo or regioselectivity. The focus is also placed on type of monomers or the conditions of polymerization. In this part of thesis are also described general methods for their synthesis. Found analogies and generalization are commented from the point of view of the design of the catalytic systems for the purpose of choosing the stereo or regioselectivity, molar mass and its distribution. This gives significance to these complexes as catalytic systems for obtaining the required polymer properties. The acquired knowledge is used for the theoretical design of the catalytic system for controlled polymerization.
|
|
|
PLA Synthesis in Solution
Svítil, Jan ; Zdeněk, Přikryl (referee) ; Petrůj, Jaroslav (advisor)
This thesis is studying PLA syntheses using polymerization of lactides in solution. Theoretical part deals with properties and production of lactic acid, lactides and polylactides. In the experimental part, possibilities of lactides polymerization in solution has been summerised and verified. Syntheses were performed via “solvothermal” method using 7 solvents (toluene, chloroforme, 1,2-chlorobenzene, acetone, tetrahydrofurane, cyclohexane and hexane). Using hexane as solvent, at concentration ratio catalyzer/lactide 1 : 1 000, polymerization temperature 160 °C and reaction time 20 h, polylactide of viscosity average molecular weight 179 000 gmol–1 was synthetized from the lactide.
|
|
|
Gel polymer electrolytes modified by ionic liquids with aprotic solvents
Pospíšilová, Michaela ; Sedlaříková, Marie (referee) ; Jahn, Michal (advisor)
This graduate thesis is focused on measuring the electrical conductivity of the gel polymeric electrolytes, their preparation and deals with the changes of the performance ratio of the individual substances in gel electrolyte The theoretical part deals with electrochemistry, gel electrolytes, the conductivity of electrolytes, gel electrolytes preparation, methods used to evaluate the measured results and on the properties of the ionic liquids. In the practical part is summarized the process of preparing gel electrolytes, the chemicals to prepare the gels with ionic liquids. The results are evaluated by using impedance technique and linear voltammetry, there are calculated the values of the electrical conductivity of the electrolyte and potential windows.
|
|
|
Preparation and characterisation of encapsulated biogenic nanoparticles for medical application
Poláková, Veronika ; Vojtová, Lucy (referee) ; Brtníková, Jana (advisor)
Cieľom tejto bakalárskej práce je príprava a polymérová enkapsulácia antibakteriálnych biogénnych nanočastíc, tak aby sa zvýšila stabilita, znížila cytotoxicita a bola zachovaná ich antibakteriálna aktivita. Teoretická časť obsahuje informácie o regeneratívnej medicíne, bežne používaných nanoštruktúrach v regeneratívnej medicíne, ich vlastnostiach a metódach enkapsulácie. Experimentálna časť popisuje procesy prípravy selénových nanočastíc za použitia rôznych metód so špecifickými stabilizátormi a pokračuje enkapsuláciou do prírodného polyméru. Použité metódy enkapsulácie sú založené na samostatnej polymerizácii a pokrývaní vybraným, v prírode sa vyskytujúcim polymérom s adhezívnymi vlastnosťami. Boli skúmané chemické a fyzikálne vlastnosti čistých a enkapsulovaných selénových nanočastíc, ako je ich koncentrácia a morfológia (veľkosť a tvar), boli skúmané pomocou infračervenej spektrofotometrie s Fourierovou transformáciou a skenovacej transmisnej elektrónovej mikroskopie. Bolo zistené, že rôzne metódy poskytnú nanočastice s rôznou veľkosťou, tvarom a stabilitou. Hlavným výsledkom je vytvorenie a popísanie optimalizovanej metódy syntézy selénových častíc, ich stabilizácia a enkapsulácia. Nanočastice syntetizované touto metódou majú sférický tvar a ich veľkosť sa pohybuje v rozmedzí od 10.5 do 101 nm. Veľkosť väčšiny takto syntetizovaných nanočastíc leží v intervale od 10.5 do 40 nm. Enkapsulované nanočastice sú väčšie a pohybujú sa v hodnotách od 74.5 do 571.5 nm.
|
|
| |
|
|
Gel Polymer Electrolytes for Electrochemical Power Sources
Jahn, Michal ; Bartušek, Karel (referee) ; Paidar,, Martin (referee) ; Sedlaříková, Marie (advisor)
Dissertation thesis is focused on study of gel polymer electrolytes for electrochemical power sources, but also for other application. The electrical, electrochemical, mechanical and optical properties of gel electrolyte samples were measured in this work. The main goal was to prepare samples with high specific conductivity and with largest possible potential windows. Thermal stability of some samples was also monitored using thermogravimetric analyzes. The optimization of the chemical composition, quantities and ratios of individual chemicals has been made. Comparison of thermal polymerization and UV polymerization was performed. In the first part of the work, aprotic solvents and their mixtures in combination with lithium and sodium salts and one ammonium salt were investigated. Another subject of research was various crosslinking agents with methacrylate-based monomers. The second part of the work investigated the effect of ionic liquids, phosphor base flame retardants and nanoparticles as additives to gel electrolytes. In the last part of the work, the influence of the magnetic and electric field on the polymerization of gel electrolytes containing nanoparticles and selected copolymers was studied. Finally, a Li-ion cell with a graphite anode, LiFePO4 cathode and selected gel electrolyte was assembled.
|
|
|
synthesis of conjugated polyacetylene based polymers
Duchoslavová, Zuzana ; Zedník, Jiří (advisor) ; Doubský, Jan (referee)
Mostly new acetylene based monomers were prepared. All monomers were prepared by the means of standard spectroscopic methods. All monomers were successfully polymerized using standard metathesis TaCl5 based catalyst. Prepared polymers were characterized by the means of GPC/GPC-MALLS chromatography and standard spectral methods. Fluorescence properties of all prepared compounds were also studied: quantum fluorescence yields were determined and excitation and emission fluorescence spectra were recorded. Polymerization on modern metathesis Grubbs-Hoveyda catalytic systems of all prepared monomers was also tested. These reactions were only partially successful and only low molecular weight oligomers in mediocre yields were obtained.
|
|
|
Preparation and polymerization ethynyl pyridine based monomers
Faukner, Tomáš ; Zedník, Jiří (advisor) ; Hoškovec, Michal (referee)
A group of monomers based on disubstitued ethynylpyridine (3-PyCCPh-4-t-Bu, 2-PyCCR, R = 4-t-BuPh, 2-Py, n-Bu) and 4-tert-butyphenylethynyl (4-t-BuPhCCPh-p-OR, R = SiPh2-t-Bu, Si-i-Pr3) were prepared by Sonogashira cross-coupling reaction (PdCl2[(PPh3]2/CuI). All of these monomers were charakterized by IR, UV/vis and NMR spectroscopy. Ethynylpyridine based monomers were polymerised by quarternization (ethylbromid was used as a quarternization agent) and by Grubbs-Hoveyda 2nd generation catalyst. As a product of the quarternization were obtained oligomers compounded by 2 - 13 monomers units (Mw: 1600 - 6000, Y 70%). Only low molecular weight oligomers were also obtained by Grubbs-Hoveyda 2nd generation polymerization (Mw: 400 - 1500, Y 34 %). Monomers based on 4-tert-butyphenylethynyl were polymerized by TaCl5/Bu4Sn/Toluen catalytic system. In that case were obatined polymers (Mw: 64 000 - 200 000, IP = 2,3 -3,9, Y 75 %). Products of polymeryzations were charakterized by GPC, IR, UV/vis and NMR spectroscopy.
|
|
| |
|
|
Study of molecular weight and configurational stability of substituted polyacetylenes
Trhlíková, Olga ; Sedláček, Jan (advisor) ; Netopilík, Miloš (referee) ; Žigon, Majda (referee)
3 ABSTRACT Complexes [Rh(cycloolefin)(acac)] (cycloolefin = norborna-2,5-diene, cycloocta- 1,5-diene and cyclooctatetraene) were investigated as catalysts of polymerization of monosubstituted acetylenes into stereoregular cis-transoid polyacetylenes. All complexes were highly active in arylacetylenes polymerizations in both coordinating and non-coordinating solvents. Selection of solvent and cycloolefin ligand of the catalyst allowed the control over polymer MW. The onset of initiation in the [Rh(cycloolefin)(acac)]/monomer systems proceeded as the proton transfer from the monomer molecule to the acac ligand under the release of acetylacetone and coordination of -C≡CR ligand to Rh(cycloolefin) moiety. Cis-transoid poly(phenylacetylene) and poly[(2,4-difluorophenyl)acetylene]s with required initial MW were prepared with these catalysts and submitted to the long-term ageing in which the polymers were exposed to the atmosphere and diffuse daylight either dissolved in tetrahydrofuran or in the solid state. Tightly connected processes of cis-to-trans isomerization of the polymer main-chains double bonds and oxidative degradation were found to proceed during polymers ageing in the solution. Besides, the formation of corresponding cyclotrimers accompanied the polymers ageing. However, the cyclotrimers amount was...
|
guest ::
