|
|
Involvement of vibrational spectroscopy in the in-situ analysis of PHA in bacterial biomass.
Kevélyová, Barbora ; Samek, Ota (referee) ; Sedláček, Petr (advisor)
The aim of this thesis was the study of polyhydroxyalkanoates in bacterial biomass using the ATR-FTIR method. Furthermore, the PCA method was chosen to evaluate the measured data and observe correlations or differences among the spectra of various biomass samples. The bacterial producents were Aneurinibacillus thermoaerophilus H1, AH30 and AFn2, Cupriavidus malaysiensis DSM 25816, DSM 19416 and DSM 19379 and three strains of Schlegelella thermodepolymerans M 15344, DSM 15264 and LMG 21645. Various heteropolymers with different monomer content and total PHA content were investigated. The monomers in the samples were 3-hydroxybutyrate, 4-hydroxybutyrate, 3-hydroxyvalerate, 4-hydroxyvalerate, 5-hydroxyvalerate and 4-hydroxyhexanoate. As the reference method for accurate quantitative and qualitative determination of polyhydroxyalkanoates in the samples, gas chromatography was performed. The spectra obtained by the FTIR method were compared and significant peaks related to the qualitative properties of PHA, namely monomer composition and crystallinity, were searched for. The PCA statistical method was successfully applied to the collected data from FTIR, with the help of which the qualitative differences between the samples were monitored. The most significant differences were observed in the presence of monomers 4-hydroxybutyrate and 4-hydroxyhexanoate, and they were related to the crystallinity of the samples. The analysis did not show potential for semi-quantitative determination of PHA in biomass. Differences between microorganisms were not observed. The procedure for evaluating FTIR spectra using PCA could in the future be used in the study of biomass containing various monomeric units, especially hydroxyvalerates in case of their higher content within the sample.
|
|
|
New gel electrolytes based on copolymers for electrochemical power sources
Peterová, Soňa ; Sedlaříková, Marie (referee) ; Veselkova, Iuliia (advisor)
This thesis deals with description of preparation and use of monomers and copolymers for gel polymer electrolytes usable in electrochemical power sources. This thesis is divided in theoretical and experimental part. The theoretical part describes electrolytes focused on gel polymer electrolytes, measuring methods and materials used for experiments. The experimental part deals with calculation of composition of polymer electrolytes, method of preparation and evaluation of measured results. The method of applying GPE to a negative LTO electrode and a positive NMC electrode is described too. Linear Sweep Voltammetry (LSV) and Potentiostatic Electrochemical Impedance Spectroscopy (PEIS), Cyclic Voltammetry (CV) and Galvanostatic Cycling with Potential Limitation (GCPL) were chosen for measurement of properties.
|
|
|
Technologies using organic materials
Galbička, Tomáš ; Chmela, Ondřej (referee) ; Hubálek, Jaromír (advisor)
There are sumarized some of the basic organic materials for produce of organic parts. Two types of theese materials are introduced PPV and PFV and their derivatives, which tuning their resulting properties in area of electrical, optical, chemical, and thermal parameters. There is designed and created system for mechanical bending of adhesive SMD devies on flexible printed circuit board and compared properties of some conducting adhesives.
|
|
|
Biotechnological production of PHA by selected thermophilic bacteria
Marková, Lucie ; Slaninová, Eva (referee) ; Pernicová, Iva (advisor)
This thesis is mainly focused on the production of PHA copolymers and study of metabolism of the thermophilic genus Aneurinibacillus. Theoretical part mainly deals with general characterization and production of PHA and with PHA producing bacteria, especially the extremophiles. The last chapter talks about the bacterial genus Aneurinibacillus and previous knowledge about this PHA producer. The experimental part is focused on testing the PHA synthase from Aneurinibacillus, which can synthesize large scale of different monomers. The two bacterial isolates, AFN2 and AH30, were used to produce copolymers with unsusual monomers in their structure, such as 3HB, 3HV, 4HB, 4HV, 5HV and even 3HHx and 4HHx. This means that the PHA synthase has low substrate specifity. The production of copolymers was supported by adding precursors which encompass lactones, diols and organic acides. There were used two different types of medium. The mineral medium, which generate the environment with limited content of nitrogen, and complex medium, which provide to bacteria all required elements. It was observed that the genus Aneurinibacillus don´t require the nitrogen limitation to produce PHA. One of the most successful experiments was the cultivation of AFN2 on complex medium with added glucose and -valerolactone as precursor. The concentration of biomass was 4,2 g/l and the syntesized PHA reached 2,6 g/l. This copolymer was composed nearly of 60 mol. % monomer 4HB. In the last section of experimental part the two pair lacton-diol were selected to produce more PHA copolymer wich was later isolated and characterized. When the lactone was used as precursor, the resulting PHA copolymer reported higher molecular weight. This can be explained by alcoholytical activity of PHA synthase from bacterial genus Aneurinibacillus.
|
|
|
Self-assembled polymer systems responsive to external stimuli for biomedicine
Sincari, Vladimir ; Štěpánek, Petr (advisor) ; Matějíček, Pavel (referee) ; Sedláková, Zdeňka (referee)
The first work in my doctoral thesis described a novel rapid and eco-friendly reversible addition-fragmentation chain transfer (RAFT) polymerization reaction of the N-(2- hydroxypropyl) methacrylamide (HPMA) monomer under microwave irradiation (MWI). Optimal conditions for the polymerization such as reaction time, solvents, monomer stoichiometry and RAFT agents was determined. The polymerization kinetics demonstrated the linear increase in the number-average molecular weight (Mn) with monomer conversion. Good agreement between the theoretical and experimental Mn values was verified with pseudo-first- order kinetic plots, with low dispersities (Đ ≤ 1.04). Furthermore, this publication demonstrated the ability of MWI to facilitate copolymer formation by the preparation of relevant copolymers, such as poly(HPMA-b-bocAPMA), poly(HPMA-b-MABH) and poly(HPMA-b-PDPA) which were used as a base for the following work in the thesis. The second and third study are devoted to delivery of therapeutic molecules by using cargo-delivery self-assemblies in the form of polymersomes (PS). Such drug delivery systems (DDS) potentially minimize the premature degradation of drug, fast clearance from bloodstream and dosing frequency which leads to lower toxicity. The main advantage of DDS is the controlled manner of drug...
|
|
|
Interactions in solutions and gels of stimuli-responsive polymer systems investigated by NMR spectroscopy
Konefał, Rafał ; Spěváček, Jiří (advisor) ; Hrabal, Richard (referee) ; Štěpánek, Miroslav (referee)
Stimuli-responsive (stimuli-sensitive, intelligent, or smart) polymers are polymer materials which, after small external stimuli, evidently change their physical or chemical properties. Smart polymers can be classified according stimuli they respond to such as: temperature changes, mechanical stress, light irradiation, ultrasonic treatment, application of external magnetic as well as electric field, changes of pH, ionic strength, addition of the chemical agents and presence of biomolecules and bioactive molecules. Stimuli-responsive synthetic polymer systems has attracted considerable attention due to wide range of applications, i.e. controlled drug delivery and release systems, diagnostics, tissue engineering and 'smart' optical systems, as well as biosensors, microelectromechanical systems, coatings, and textiles. Among the types of stimuli for this dissertation temperature, pH and reactive oxygen species (ROS) responsive polymer systems were studied. In case of thermoresponsive polymers, when polymer chains are molecularly dissolved in a good solvent, changes (increasing or decreasing) of temperature result in insolubility (globular nanoparticles formation) of polymer chains, called temperature induced phase-separation. pH responsive polymers change properties such as: solubility, volume (gels),...
|
|
| |
|
|
New Gel Electrolytes Based On Copolymers For Electrochemical Power Sources
Peterová, Soňa
This paper deals with description of preparation and use of monomers and copolymers for gel polymer electrolytes usable in electrochemical power sources. The paper is divided in theoretical and experimental part. The theoretical part describes gel polymer electrolytes and chemical substances used for experiments. The experimental part deals with composition of gel polymer electrolytes, method of preparation and evaluation of measured results.
|
|
|
Nanoparticles formed by complexes of copolymers with low-molar-mass compounds
Vojtová, Jana
This thesis is focused on mixed systems of various copolymers (double hydrophilic block and gradient polyelectrolytes, hydrophobic graft copolymers) and low-molar-mass compounds (sodium dodecyl sulfate as a representative of a ionic surfactant or superparamagnetic iron oxides in the form of nanocrystals). The electrostatic and hydrophobic interactions in the studied systems in aqueous solutions leading to aggregation behavior and to the formation of co-assembled nanoparticles were investigated by combination of scattering and microscopy techniques, including light, X-ray and neutron scattering, electron microscopy and atomic force microscopy. Powered by TCPDF (www.tcpdf.org)
|
|
|
Oriented copolymers with liquid crystalline building blocks
Horodecka, Sabina Jolanta ; Strachota, Adam (advisor) ; Uchman, Mariusz Marcin (referee) ; Sedláková, Zdeňka (referee)
Several series of reversible physical networks based on polydimethylsiloxane (PDMS) chains and liquid crystalline (LC) structural units were synthesized and studied, which belong to three different architecture types: (1) LC-grafted PDMS (with LC quartets at the grafting sites), (2) LC-end-capped linear PDMS, (3) and linear 'infinite' LC-PDMS copolymers (with alternating LC and PDMS segments). PDMS spacers of different lengths of were tested, as well as 6 different polyaromatic mesogens of azo type and azo-free type. Hydrosilylation coupling of vinyl-functional mesogens, obtained as part of an international cooperation, with commercial Si-H-functional PDMS was employed to synthesize all the studied materials. The copolymers were physically crosslinked by the nano-aggregation of the LC units contained in their macromolecules. The thermotropic properties of the LC-nano-aggregates lent interesting physical properties to the whole material, making some of the copolymers attractive as potential smart materials. The PDMS spacer segments were selected for the sake of their extreme flexibility, which should provide elastic properties to the physically crosslinked copolymers, and also because of their (desired) incompatibility with the mesogens. This latter effect was highly helpful for achieving the...
|
guest ::
