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Study of molecular weight and configurational stability of substituted polyacetylenes
Trhlíková, Olga
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 too...
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Gel polymer electrolytes with nanoparticles
Szotkowski, Radek ; Sedlaříková, Marie (referee) ; Jahn, Michal (advisor)
This master‘s thesis concerns gel polymer electrolytes formed on a methyl methacrylate base with selected types of nanoparticles. In the thesis are also analyzed the methods for measuring electrochemical properties. The practical portion deals with sample preparations of gel polymer electrolytes with different contents of alkaline salt in a solvent, creating gels with different nanoparticle content and comparing gel polymer electrolytes polymerized with heat and UV radiation. The thesis deals with the evaluation of these samples from the viewpoint of electrical conductivity and potential windows as well as thermal analysis of selected samples.
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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.
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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.
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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.
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Lanthanocene Catalysts for Synthesis of Polymers Applicable in Medicine
Slanina, Ondřej ; Kábelová, Božena (referee) ; Richtera, Lukáš (advisor)
The theoretic part of the thesis focuses on materials used in medicine. The metallic, ceramic, glass-ceramic and polymer materials are systematically described. The biocompatibility of the materials and possible threads of their usage for manufacturing of medicinal devices and implants are emphasized in the discussion. The work is focused especially on polymer materials. Different types of polymerizations are summarized with the accent on the preparation of biodegradable materials. In the practical part the synthesis of two organometallic bis(pentamethylcyclopentadienyl) sandwich complexes with holmium and gadolinium as a central atom designed for preparation of materials suitable for biomedicine is proposed.
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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.
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SMV-2013-19: Nanolithography system based on two-photon photopolymerization
Jákl, Petr ; Šerý, Mojmír ; Zemánek, Pavel
The reasearch contract deals with development of experimental setup for dynamic shaping of laser beams. Using computer generated holographic phase masks, it is possible to create independent foci of laser beams in the sample space, change their intensity profiles and power of each diffracted beam. By employing fast acousto-optic modulator, the complex procedure allows control of sample irradiation within microsecond resolution. It is possible to precisely select sample region for laser impact using computer-controlled nano-positioning stage.
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