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Functionalization of polyolefins by grafting
Paulenka, Igor ; Petruš, Josef (referee) ; Petrůj, Jaroslav (advisor)
The theoretical part of the diploma thesis is focused on the funcionalization of polyolefins in order to accelerate their degradation and to increase their carbon content from renewable resources with focus on hydroxyacids. The experimental part is focused on preparing samples and studying the properties of the polypropylene and polyethylene blends with the polylactide with different contents of the initiator and the maleic anhydride. Samples were evaluated by determining the degree of conversion maleic anhydride, differential scanning calorimetry, infrared spectroscopy, melt flow index and mechanical properties.
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Grafting of polypropylene with derivatives of itaconic acid
Poštulková, Hana ; Běťák, Lukáš (referee) ; Kučera, František (advisor)
Bachelor thesis deals with grafting of polypropylene (PP) by using derivatives of itaconic acid (IA) in the melt phase, specifically with monomethyl itaconate (MMI) and dimethyl itaconate (DMI). Theoretical part focuses on summary of radical initiated grafting of PP with different monomers especially DMI and MMI and factors influencing radical grafting. In experimental part were prepared samples with concentration of monomer 1-5 wt. % and concentration of initiator 1,5-0,15 wt. %. Influence of concentration of monomer, ratio of monomer concentration to initiator concentration and temperature on concentration of grafted monomer and conversion were determined. A Brabender mixer was used for all experiments. Conditions of grafting were 75 rpm, time of reaction 6 minutes and temperature 180-200 °C, initiator Luperox 101. Degradation of polymer chain was determined by MFI. Infrared spectroscopy (FTIR) was used to calculate monomer conversion and concentration of grafted monomer.
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Radical grafting of PE/PP copolymer
Šido, Jiří ; Petrůj, Jaroslav (referee) ; Kučera, František (advisor)
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.
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Modification of boron doped diamond electrode by electrochemical oxidation of p-aminobenzoic acid
Švárová, Eliška ; Fischer, Jan (advisor) ; Dejmková, Hana (referee)
This bachelor's thesis deals with the modification of a boron-doped diamond electrode (BDDE) by the electrochemical oxidation of p-aminobenzoic acid. Subsequently, the stability of the modified electrode was investigated by a study of various parameters. The modification of the electrode was performed using cyclic voltammetry (CV) in LiClO4 electrolyte. The success of the modification and its subsequent stability was investigated by the CV method in electrolyte KCl in the presence of the redox system [Fe(CN)6]4-/3- . Stability was tested in terms of ultrasonic cleaning in isopropanol and anodic cleaning in 0.5 mol l-1 H2SO4. It was found that the modification of the surface cannot be completely removed by ultrasonic cleaning in isopropanol, in contrast, pulses of period 2 seconds with a high positive potential are enough to completely remove the modification. Optimal conditions for surface stability were determined. The ideal number of cycles for surface modification was set at 5 cycles. The use of different electrolytes during modification (KClO4 and LiClO4) determined that in the case of modification in the KClO4 electrolyte, it is possible to measure in the range of the potential window from -400 to +1600 mV and in the case of LiClO4 in the range of -400 to +1500 mV without breaking the modified...
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Testing of new electrode arrangements for monitoring of electrochemically oxidisable biologically active organic compounds
Libánský, Milan
Submitted Ph.D. Thesis is focused on the electrochemical characterization and testing of recently developed working electrodes made from pure gold or graphitic carbon particles and electrochemical arrangements. These electrodes are suitable for large screening measurements of various organic compounds. The development of new sensitive voltammetric methods for determination of oxidisable biologically active organic compounds is another aim of this work. To verify its applicability, the array of carbon composite film electrodes integrated in measuring cell system was selected for the development of voltammetric methods for determination of homovanillic acid, vanillylmandelic acid, and indoxyl sulphate. These analytes, which belong to the group of biomarkers of human diseases, were selected for increasing interest in their determination in medical laboratories. Moreover, determination of indoxyl sulphate was coupled to its solid phase extraction from human urine prior to voltammetric determination. Obtained results were compared with measurements of standards with well-established carbon paste electrode. Sputtered (physical vapour deposition method) gold nanostructured film electrodes on treated PTFE substrates and gold nanostructured film electrodes modified with various functional groups on the...
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Modification of Polyethylene by Reactive Compounding
Horkel, Ondřej ; Kučera, Jaroslav (referee) ; Petrůj, Jaroslav (advisor)
This Master’s thesis deals with the problematics of radically initiated compounding of polyethylene by 1-vinyladamantane. Theoretical part focuses on the theory of grafting processes and how they are influenced by chosen process parameters, as well as the properties of used monomer. In experimental part, two sets of experiments were designed, in both cases the chemicals used were polyethylene LITEN MB 87, (2,5-dimethyl-2,5-bis(tert-butylperoxy) hexane), also called Trigonox 101, as the initiator, and chemicals called Ionol and Irgafos 168 as stabilizers. The experiments were carried out in a Brabender batch mixer, the temperature was 180 – 185 °C, the reaction time was 5 minutes. The analytic methods used to evaluate the prepared samples’ properties were the tensile testing, the Charpy notch test, measuring of the melt flow index, analyzing the torque during kneading and the analysis of infrared spectra of the samples. By carrying out of these experiments it was found that excessive crosslinking was present with mass fraction of initiator being as low as 2 %. It was also concluded that under these conditions the modification does not improve tensile properties of the material, but it does improve the impact strength, albeit slightly. The influence of the modification on flow properties needs to be investigated further. A presence of vinyl groups was observed in infrared spectra, suggesting the presence of ungrafted vinyladamantane.
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Detekce fytopatogenů jahodníku
MICHÁLKOVÁ, Barbora
Strawberries were tested for presence of selected phytopathogens (Agrobacterium, Rhodococcus, phytoplasmas, SMYEV, SMoV, SPV1, SCV and SCRh1) by the PCR. At the same time was researched the transmission of mentioned phytopathogens by grafting. The DNA of the strawberries with positive results was sequenced.
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Grafting VTMOS onto PHB
Novotný, Igor ; Petruš, Josef (referee) ; Kučera, František (advisor)
Diploma thesis deals with the grafting of vinyltrimethoxysilane (VTMOS) onto poly(3–hydroxybutyrate)PHB. Subsequent characterization of the amount of grafted VTMOS and changes in the thermal properties associated with the rate of crystallization. The theoretical part deals with mechanism and the influences of grafting. In the experimental part VTMOS was grafted onto PHB without subjecting VTMOS to hydrolysis and subsequent crosslinking. By differential scanning calorimetry (DSC) and Avrami equation, the effect of grafted silane group on pure was studied. The MVR was used to compare the rheological properties of initial PHB, grafted PHB and crosslinked PHB by siloxane linkages.
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Testing of new electrode arrangements for monitoring of electrochemically oxidisable biologically active organic compounds
Libánský, Milan
Submitted Ph.D. Thesis is focused on the electrochemical characterization and testing of recently developed working electrodes made from pure gold or graphitic carbon particles and electrochemical arrangements. These electrodes are suitable for large screening measurements of various organic compounds. The development of new sensitive voltammetric methods for determination of oxidisable biologically active organic compounds is another aim of this work. To verify its applicability, the array of carbon composite film electrodes integrated in measuring cell system was selected for the development of voltammetric methods for determination of homovanillic acid, vanillylmandelic acid, and indoxyl sulphate. These analytes, which belong to the group of biomarkers of human diseases, were selected for increasing interest in their determination in medical laboratories. Moreover, determination of indoxyl sulphate was coupled to its solid phase extraction from human urine prior to voltammetric determination. Obtained results were compared with measurements of standards with well-established carbon paste electrode. Sputtered (physical vapour deposition method) gold nanostructured film electrodes on treated PTFE substrates and gold nanostructured film electrodes modified with various functional groups on the...
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Testing of new electrode arrangements for monitoring of electrochemically oxidisable biologically active organic compounds
Libánský, Milan ; Zima, Jiří (advisor) ; Navrátil, Tomáš (referee) ; Šelešovská, Renáta (referee)
Submitted Ph.D. Thesis is focused on the electrochemical characterization and testing of recently developed working electrodes made from pure gold or graphitic carbon particles and electrochemical arrangements. These electrodes are suitable for large screening measurements of various organic compounds. The development of new sensitive voltammetric methods for determination of oxidisable biologically active organic compounds is another aim of this work. To verify its applicability, the array of carbon composite film electrodes integrated in measuring cell system was selected for the development of voltammetric methods for determination of homovanillic acid, vanillylmandelic acid, and indoxyl sulphate. These analytes, which belong to the group of biomarkers of human diseases, were selected for increasing interest in their determination in medical laboratories. Moreover, determination of indoxyl sulphate was coupled to its solid phase extraction from human urine prior to voltammetric determination. Obtained results were compared with measurements of standards with well-established carbon paste electrode. Sputtered (physical vapour deposition method) gold nanostructured film electrodes on treated PTFE substrates and gold nanostructured film electrodes modified with various functional groups on the...
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