|
|
Assessment of 3D printing technology as an alternative in manufacturing
Balvín, Patrik ; Šafl, Pavel (referee) ; Binar, Tomáš (advisor)
This bachelor thesis is devoted to 3D printing. The main methods od 3D printing, widely used materials (their production, their properties and the advantages and disadvantages of using them), degradation due to enviromental conditions, other common methods of producing polymer parts and mechanical test are described in the theoretical part. This paper also compares the advantages of using 3D printing for prototyping. The experimental section is dedicated to measuring the impact of material degradation on the toughness, hardness, and tensile strength of PLA and PA6 CF15 materials. The case study focuses on the design of an engine spark coil holder and a mobile workstation for 3D printing.
|
|
|
LIBS detection of trace elements in polymeric matrice
Kočenda, Dominik ; Kopřivová, Hana (referee) ; Krčma, František (advisor)
When recycling plastic materials, it is important to determine whether they contain concentrations of hazardous impurities, such as heavy metals, above permissible limits. This bachelor's thesis focuses on quantifying cadmium in a polymer matrix using Laser-Induced Breakdown Spectroscopy (LIBS). Samples of polypropylene and polystyrene with unknown cadmium concentrations were examined. Calibration samples for both types of polymers were prepared for quantification and then analyzed using Inductively Coupled Plasma Mass Spectrometry (ICP-MS) in an external laboratory. These results were used as calibration values for the LIBS method and also to verify the accuracy of the obtained results. Calibration curves for cadmium were created from the calibration samples, which enabled the determination of unknown cadmium concentrations in the polypropylene and polystyrene samples and the determination of the detection limit of cadmium using the LIBS method. Cadmium in the unknown samples was quantified with an average accuracy of 90 % and precision of 85 %.
|
|
|
Pharmacokinetics of Intramuscularly Administered Thermoresponsive Polyacrylamides
Groborz, Ondřej
6 Pharmacokinetics of Intramuscularly Administered Thermoresponsive Polyacrylamides Author: Ondřej Groborz Supervisor: doc. Mgr. Martin Hrubý, Ph.D., DSc. Institute of Macromolecular Chemistry, Czech Academy of Sciences Advisers: Ing. Pavel Švec RNDr. Lenka Loukotová, PhD. Abstract Polymer solutions with lower critical solution temperature (LCST) undergo a phase separation when heated above their cloud point temperature (TCP). These thermoresponsive polymers have numerous promising medicinal applications, such as in situ depot-forming radiotherapy (brachytherapy), controlled drug-release, immuno-radiotherapy, injectable thermogelling for tissue engineering and cell culture and magnetic resonance imaging (MRI), among others. Yet, despite extensive research on medicinal applications of thermoresponsive polymers, their fate after their administration remains largely unknown. Thus, in our study, we synthesized and thoroughly characterized four different thermoresponsive polyacrylamides, namely poly(N-(2,2-difluoroethyl)acrylamide), poly(N- isopropylacrylamide), poly(N,N-diethylacrylamide) and poly(N-acryloylpyrrolidine) under physiologically relevant conditions. Subsequently, we determined their biodistribution kinetics in mice and proposed a data-based pharmacological model to describe their in vivo behaviour,...
|
|
|
Design of manufacturing technology for plastic terminal device
Adamiec, Pavel ; Žák, Ladislav (referee) ; Kandus, Bohumil (advisor)
The master thesis deals with design to produce terminal using the plastic injection molding. In the first part are theoretical information about injection molding and injection molding with inserts. The second part is a concrete design of production terminal which contains: injection mold design, calculation of the injection parameters, machine selection, technical and economic evaluation of production. Terminal is made of polyamide 66, inserts material is brass. Parts of injection mold assembly are selected from Hasco standards. The main parts of assembly are made of 1.2312 steel. Production cycle is placed on injection machine Allrounder 375 V from Arburg.
|
|
|
Metallization of technical plastics for lightweight traffic components with reduced fuel consumption
Sanetrníková, Dominika ; Boušek, Jaroslav (referee) ; Šimůnková, Helena (advisor)
The beginning of this thesis is dedicated to polymeric materials, which include plastics an composites. Plastics are shortly divided into two groups, thermoplastics and thermosets. The following part is the use of plastics and composites in traffic industry and briefly this work focuses on techniques of recycling of this materials. This work also focuses on the techniques of thin film deposition, electroless plating, electrodeposition as well and plating in the vacuum environment. special techniques of thin film deposition are also mentioned shortly. The coatings of polymer including cleaning and surface activation is introduced using various techniques including plasma treatment. The surface treatment of polyetheretherketone (PEEK) is included too. The final part describes performed experiments and discussion of results.
|
|
|
Hydrogen quantification by electron spectroscopy
Endstrasser, Zdeněk ; Polčák, Josef (referee) ; Čechal, Jan (advisor)
The absence of hydrogen in the photoelectron spectrum remains one of the greatest limitations of X-ray photoelectron spectroscopy. The main aim of this work is therefore to determine the concentration of hydrogen atoms in the near surface region of a sample. The REELS electron spectroscopic method based on quasi-elastic electron scattering is used for this purpose. The choice of this method was given mainly by the fact that the photoelectron spectrometers has an electron source in the basic equipment, so there is no requirement to purchase additional equipment. In our case, measurements were realized using the AXIS Supra photoelectron spectrometer in CEITEC laboratories. We were primarily focused on the study of polymer samples in this work. The gus cluster ion source was used for sputter cleaning of the sample surface. Then the XPS and REELS measurements were performed on such cleaned samples. The obtained data were subsequently evaluated, and the results discussed. The most important output of this work was to develop the methodology of detection and quantification of hydrogen atoms. However, the theoretical description of the methods used, and the appreciation of critical aspects associated with the use of the REELS method are also embraced. In particular, the effect of sample charging and electron dose on measurement results is discussed.
|
|
|
Energy Chains
Oríšek, Petr ; Němec, Karel (referee) ; Molliková, Eva (advisor)
The thesis points to the importance of energy chains in the engineering practice and the wide range of their usage. The elaboration of this topic includes presentation of various types of energy chains, information about their construction, application and history. The emphasis is put on defining the properties that the chosen material must have in order to meet all requirements for energy chain. The thesis provides general information about the materials suitable for production of the chains and their properties and presents concrete materials used in the practice. Furthermore, a part of the work is dedicated to flexible cables which are inserted to the energy chains and their properties. There is a number of companies producing energy chains worldwide. The thesis makes use of the information furnished by one of these companies.
|
|
|
Preparation of Poly(3-hydroxybutyrate) based acrylic monomer
Liška, Marek ; Přikryl, Radek (referee) ; Figalla, Silvestr (advisor)
The main aim of this thesis is to research and prepare acrylic (methacrylic) monomers derived from poly(3-hydroxybutyrate). The monomers were prepared in two-step syntheses. In the first step P3HB was depolymerised with selected alcohols and afterwards, products of those syntheses were used as substrate and mixed with polymethylmethacrylate to produce their methacrylic derivates. The selected alcohols for the alcoholysis were ethanol and ethylene glycol. In total, four substances were prepared. Products of alcoholysis were ethyl-3- hydroxybutyrate, 2-hydroxyethyl-3-hydroxybutyrate and their methacrylic derivates. Significant part of this thesis is aimed towards the analysis of prepared substances and the analysis of reactions. In the process, titrations and instrumental methods, such as gel permeation chromatography (GPC), infrared spectroscopy (FTIR), nuclear magnetic resonance (NMR), thermogravimetry (TGA) and differential scanning calorimetry (DSC) were used. This work describes preparation and analysis of polymers prepared from methacrylates from the mentioned syntheses. Cross-linked polymers, because of their low glass-transition temperature are elastomers.
|
|
|
Construction of gears with plastic teeth
Selzer, Tomáš ; Vrbka, Martin (referee) ; Křupka, Jiří (advisor)
The thesis discusses the matter of construction of gear trains using plastic parts in both lubricated and non-lubricated environment, trying to give an overview of an up-to-date information in the process. Nowadays, thanks to several years of development, polymer-based gear systems can be used in many cases as a replacement for metal-based ones. The undeniable advantage of such replacement is mostly the lower production cost and its lower weight, which, together with favorable friction properties of polymer materials, makes a number of technological applications much more effective. The first part is dedicated to listing and defining the typical characteristics of polymer materials, which are essential in the process of designing the gear. The next part focuses on evaluation of the available types of solutions for plastic gear trains construction. The last topic is centered around possible defects and the wear as well as the operation conditions and a real-life application of such plastic gear system. The most notable findings are summed up and commented on in the form a discussion. Thanks to the chosen topic, the bachelor’s thesis adds to a closer understanding of the construction and operation of the plastic gear systems.
|
|
|
Relative humidity effects on the electrical properties of silicone ruber
Pušec, Daniel ; Polsterová, Helena (referee) ; Frk, Martin (advisor)
At the beginning, this master thesis briefly describes the principle of semiconductors. It states their types, methods of operation, fields of use, and it interprets the manner of semiconductor devices’ passivation. Then it introduces silicones, their properties and usage. Later on, this thesis summerize air humidity theory and materiál moisturing including mathematical interpretation. Next chapter is devoted to basics of dielectric materials’ behavior. And finally, the last part of this thesis estimates charakteristics of passivation materiál, Dow Corning HIPEC Q1-9205 silicone rubber.
|
guest ::
