Výzkum v této práci byl zaměřen na přípravu a charakterizaci blokových kopolymerů typu polypropylen-blok-poly(propylenu-co-ethylenu) (dále jen PP-blok-EPR). Tyto materiály jsou považovány za účinné kompatibilizátory mezi semi-krystalickou polypropylenovou (PP) matricí a amorfními doménami statistického kopolymeru propylenu a etylenu (EPR) v rázuvzdorném sekvenčním kopolymeru (ICP) a proto byl výzkum zaměřen na zkoumání vlivu přídavku blokového kopolymeru PP-blok-EPR na vlastnosti komerčního ICP. Blokové kopolymery byly připraveny za použití techniky „stopped-flow“. Pro tento účel byla zkonstruována vysokotlaká polymerační „stopped-flow“ aparatura, která umožňuje syntézu kopolymerů PP-blok-EPR za podmínek blízkých podmínkám v průmyslových reaktorech pro výrobu komerčních ICP materiálů. Aparatura umožňuje vyrábět PP-blok-EPR polymer v množství dostačující na jeho charakterizaci a následnou přípravu směsí s komerčním ICP. Velmi krátké polymerační časy (obvykle kolem 0.2 s) kterých bylo dosaženo v kapilárním reaktoru aparatury „stopped-flow“ zajišťuje, že aktivní centra Ziglorova-Nattova katalyzátoru produkují polymer řetězce skládající se z bloku semikrystalického polypropylenu a bloku amorfního EPR kopolymeru. Takovéto molekuly jsou v literatuře popsány jako „skutečné blokové kopolymery PP-blok-EPR“. Kopolymery syntetizované v aparatuře „stopped-flow“ byly frakcionovány preparativní TREF (Temperature Rising Elution Fractionation) metodou a získané frakce byly následně analyzovány pomocí DSC, 13C-NMR a GPC/SEC. Tyto analýzy odhalily přítomnost amorfního EPR ve vysoce krystalické frakci (100-140 °C). Toto zjištění potvrdilo, že významná část polymerních řetězců, připravených v aparatuře „stopped-flow“ jsou blokové kopolymery skládající se z bloku semikrystalického PP homopolymeru a bloku amorfního EPR kopolymeru v jednom polymerním řetězci. Kopolymery získané metodou „stopped-flow" byly v tavenině smíchány s komerčním rázuvdorným kopolymerem ICP. U takto připravených směsí byly vyhodnoceny mechanické vlastnosti, DTMA a reologické vlastnosti a výsledky byly srovnány s vlastmi původního komerčního ICP kopolymeru. Dále byly studovány rozdíly v morfologii a umístění EPR domén v matrici PP prostřednictvím SEM. Zřetelný vliv kopolymeru PP-blok-EPR na vlastnosti ICP byl pozorován zejména v morfologických změnách EPR domén dispergovaných v PP matrici. Tyto změny mají pozitivní vliv na rovnováhu mezi modulem v ohybu a rázovou pevností ICP materiálu. Vliv kopolymeru PP-blok-EPR na reologické vlastnosti ICP byl nevýznamný. Podobně také v případě DTMA nebyl pozorován významný vliv kopolymeru PP-blok-EPR na vlastnosti ICP.

Title: Self-assembly of polyelectrolytes in aqueous solutions (dissipative particle dynamics) Author: Karel Šindelka Department: Faculty of science, Charles University in Prague Supervisor: Doc. Ing. Zuzana Limpouchová, CSc. Consultant: Doc. Ing. Martin Lísal, DSc. Abstract In the thesis, the coarse-grained dissipative particle dynamics (DPD) is used for the study of self-assembly of equimolar mixtures of oppositely charged symmetric block PEs with one PE block (either strong polycation or strong polyanion) and one readily water-soluble neutral block in aqueous media. In the first part of the diploma thesis, the principles of DPD simulations are described and the correct implementation of electrostatic interactions in the DPD method is demonstrated on the example of counterion (Manning) condensation. In the second main part, the effect of the blocks solubility, incompatibility and the interplay of different forces on electrostatic assembly is investigated. The cor- responding neutral systems are also simulated for comparison. The study shows that the hydrophobicity of the PE backbone and the incompatibility of blocks sig- nificantly affects the electrsotatic co-assembly. The presence of opposite charges on different chains promotes the aggregation process and the aggregation number in- creases in comparison...

Thesis is focused on structural study of ethylene-propylene copolymers (E/P copolymers) produced by gas phase polymerization. Goal of work was to determine the effect of used catalysts on the distribution of ethylene units in the resulting material. Three E/P copolymers were prepared on commercial Ziegler Natta catalysts with diether or phthalate based internal donors. The copolymers were fractionated according crystallization ability and molar mass. Next, the mass content and the distribution of the ethylene units in the copolymer were determined in each fraction by nuclear magnetic resonance (NMR). Together with other structural analytical methods, phthalate internal donor has been found to produce ethylene blocks under certain conditions, while the diether ID lacks this ability.

This diploma thesis deals with the isolation and characterization of copolymer P(3HB-co-4HB). The teoretical part was prepared as a literature search which describe polyhydroxyalkanoates in general, their structure, synthesis, degradation and isolation. Furthermore, copolymers containing 4HB units are mentioned in this thesis and there is also no mentioned of the biosynthesis and biodegradation of copolymer P(3HB-co-4HB). The first aim of this diploma thesis was to find out which solvent is the best for copolymer extraction and then characterize obtained copolymer P(3HB-co-4HB). The isolated copolymer was characterized by gas chromatography, SEC-MALS, thermal analysis and SEM. In the second part of the thesis, release of model biologically active substance from the PHA films was studied. Rhodamine 6G dye was selected for the simulation, which was used to stain the copolymer films and the P(3HB) films. It was observed that film prepared from P(3HB-co-4HB) copolymer released entrapped substance much faster than film made from P3HB homopolymer, and, in addition, the copolymer was substantially more susceptible to enzyme degradation.

This diploma thesis is focused on study of polymerization of hexa-1,5-diene catalyzed by phenoxy-imine titanium dichloride (FI Ti) and methylaluminoxane (MAO) as cocatalyst. Effect of monomer concentration, polymerization temperature and cocatalyst/catalyst ratio on catalytic activity, molecular weights, polydispersities and particularly microstructure of prepared poly(hexa-1,5-diene) was studied. 1H NMR spectroscopy revealed that the poly(hexa-1,5-diene) microstructure contained methylene-1,3-cyclopentane (MCP) as well as vinyl tetramethylene (VTM) units. Kinetics of this polymerization was studied. Finally, copolymer of ethene and hexa-1,5-diene possessing incorporated pendant vinyl group was prepared.

The presented thesis on thermosensitive polymer gel is focused especially on a thermosensitive triblock copolymer, which is composed of hydrophobic polylactide, polyglycolid and hydrophilic polyethylene glycol (PLGA-PEG-PLGA). Thermosensitive copolymers are very attractive for their phase sol-gel transitions and gel-suspension transitions. The aqueous solution of this copolymer behaves like a sol at laboratory temperature and like a gel at body temperature. These systems are used as injectable carriers for targeted drug delivery with controlled release. However, the influence of the resulting polymer concentration and temperature on the thermosensitive hydrogel nanostructure was not yet fully studied. In the experimental part, the viscoelastic behavior of hydrogels was observed by dynamic rheological analysis at different polymer concentrations and temperature conditions. The average size and distribution of micelles of triblock copolymer in aqueous solution were measured using dynamic light scattering technique. Characterization of fibrous micelles was complemented by imaging technique, cryogenic transmission electron microscopy.

Diploma thesis deals with preparation and characterization of block copolymer PP/PE grafted with itaconic anhydride in melt. Experimental part deals with free radical iniciated grafting of polar monomers onto polyolefins and with potencial applications of grafted polyolefins. Samples of PP/PE grafted with itaconic anhydride were prepared under various conditions in the experimental part. 2,5-dimethyl-2,5bis(tert-buthylperoxy)hexane (Luperox 101) was used as radical iniciator. Grafting was performed in Brabender mixer under conditions: temperature 190-230°C, concentration of monomer 0,25-1 weight percent, concentration of iniciator 0,025 – 2 weight percent, screw speed 30 rpm. The influence of certain parameteres: iniciator concentration, monomer concentration and temperature upon conversion of monomer, value of MFI and homopolymerization of monomer extent was of interest. Presence of anhydride bonded to the polymer backbone was confirmed by FTIR spectroscopy. Concentration of grafted anhydride and conversion of monomer was determined by acid-base titration and confirmed by FTIR spectroscopy.

Impact E/P copolymer (ICP) is produced using gas-phase polymerization catalysed by Ziegler-Natta catalysts. This material with its excellent mechanical properties is used in many industries, for example in automotive industry to produce bumpers or instrument panels. Its properties depend on chemical structure which was analysed using DSC, 13C NMR and GPC. It was used 6 different samples of ICP for studies, the chosen samples have different ratio between ethylene and propylene in their copolymer phase. The samples were fractionated using preparative TREF and solvent extraction to obtain fractions, which composition depends on elution temperature. Obtained fractions and original samples were subsequently analysed using above-mentioned methods.

This thesis is focused on the study of the properties of mortars and pastes with active pozzolanic materials. It deals with monitoring cementitious composites which describes both the effect of compensation pozzolanic cement mortar admixtures active based on amorphous silica and the modifying polymeric additive. The main criteria for the assessment of these modified mortars and pastes are particularly adhesive and achieved strength compared with the reference mortar. The detailed work also examined the microstructure past through images from REM, records RTG, DTA and high pressure mercury porosimetry.

The Diploma thesis is adressing the issue of polymer-modified mortars (PMM) and theirs properties in dependence on curing conditions. The reasons of using polymer additives and some selected applications of PMM are described in theoretical part of this work. Cementitious composite (mortar) hardening is especially focused on mechanism of formation co-matrix system based on cement hydration products and polymer film in dependence on curing conditions. The knowledge of interaction of cement and ethylene-vinyl acetate (EVA) copolymer is presented in the latest paragraphs of theoretical work. Following practical part presents influence of EVA to physical and mechanic properties of PMM in dependence of dosage polymer additive and exogenous factors. The study of microstructure was investigated by scanning electron microscope and high-pressure mercury porosimetry. Tests and investigations are described and evaluated.