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3D print of nanocomposite photopolymer systems
Sevriugina, Veronika ; Lepcio, Petr (referee) ; Ondreáš, František (advisor)
This master’s thesis deals with the preparation of nanocomposite photopolymer systems for 3D printing. The composition and structure were studied by thermogravimetry (TGA) and scanning transmission electron microscopy (STEM). The kinetics of photoreaction with gradually increasing content of Fe3O4 and AZO particles in a commercial methacrylate resin was also characterized by the creation of Jakobs working curves, photorheology, and differential scanning photocalorimetry (photo-DSC). Subsequently, the effect of composition on the printability of materials was observed. Part of the work is also devoted to the characterization of the influence of particles on the thermomechanical properties of the resulting products using dynamic-mechanical analysis (DMA) and on the mechanical properties in pressure.
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Automotive plastics with increased scratch resistance
Vida, Mikuláš ; Kučera, František (referee) ; Jančář, Josef (advisor)
The aim of this bachelor thesis was the investigation of changes of mechanical and rheological properties of nanocomposites based on PMMA, where filler was fumed silica of four types (different surface area and producer). The thesis focuses on the theoretical part of the current state of research, preparation and properties of nanocomposites. The solvent method was chosen for the preparation of nanocomposites, where silica was mixed with dissolved PMMA. Tensile mechanical properties were measured below Tg, while viscoelastic response was measured above Tg. Silica had not significant influence on the modulus below Tg, but above Tg (180 °C) both modulus, storage and loss, have increased with increasing silica content and with increasing frequency (0,1–100 Hz). The particle size and surface area of silica in a content of 1 % influenced storage modulus of nanocomposites more with respect to the content of 2 %. For samples containing 1 % showed that the significant role played particle size and surface area of silica. The greatest increase of storage and loss modulus of PMMA was reached for silica M-5 in content 1 %. All type of silica decreased tensile strength and strain with increasing silica content in the same way.
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Polymer nanocomposites with PMMA matrix
Kostková, Jana ; Žídek, Jan (referee) ; Jančář, Josef (advisor)
This bachelor thesis deals with s study of mechanical and viscoelastic properties of nanocomposites with PMMA matrix filled with different types of surface-modified silica, which differed by the specific surface area, surface treatment and particle size. Nanocomposites were prepared by dissolving, where nanofillers were injected into the dissolved matrix. Nanocomposite samples were tested in tensil and viscoelastic properties were determined till the softening point by dynamic-mechanical analysis (DMA). All types of nanofillers had almost no effect on tensile modulus of nanocomposites at room temperature (it was not reduced) one type of silica at a content 2 %, which was also confirmed by the DMA. The temperature DMA measurements showed that samples containing 2 % of silica were generally thermally more stable compared with nanocomposites containing 1 % of silica. Storage modulus of nanocomposites, except two ones, were similar or lower such pure PMMA to temperature 66 C, then the trend reversed. Loss modulus of all samples was one order of magnitude lower then the elastic modulus.
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Ceramic nanofiber-reinforced composites
Bocian, Luboš ; Přikryl, Radek (referee) ; Poláček, Petr (advisor)
This thesis investigated how the addition of unsilanized and silanized ceramic SiO2 nanofibers into particle reinforced composite affects flexural strength, fracture toughness, total fracture work and temperature dependence of viscoelastic properties. Fracture surfaces were analyzed with SEM. Flexural strength always decreased with addition of nanofibers. Composites with silanized nanofibers showed higher flexural strength than those with unsilanized nanofibers. Fracture toughness was higher with addition of nanofibers. Fracture toughness of composites with silanized nanofibers was always lower than that of systems with unsilanized nanofibers. Total fracture work was lower with addition of nanofibers, but sharply increased in composites with 5 % of nanofibers. Glass transition temperature almost always increased with addition of nanofibers. Storage modulus increased with addition of nanofibers. Storage modulus was always lower in composites with silanized nanofibers.
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Polymer nanocomposites for interior car body parts
Miškolci, Michal ; Bálková, Radka (referee) ; Jančář, Josef (advisor)
This bachelor’s thesis is interested in the problem of scratch resistance of interior car body parts. In this thesis, the solution is seen in using polycarbonate – based nanocomposites. In theoretical part, a literature search of this theme was made. In experimental part, the samples based on polycarbonate were prepared, and their tensile modulus was tested, as one of the main parameter affecting the scratch resistance.
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Application of nanofillers into thermoplastics
Žák, Luboš ; Žídek, Jan (referee) ; Kučera, František (advisor)
Bachelor thesis is focused on the search of the state of knowledge in the preparation, properties and applications of nanocomposites with thermoplastics polymer matrix and different types of nanofillers in theoretical part. Methods for the preparation of nanocomposites and techniques used for their characterization are clearly describes. The first method for preparing nanocomposites is an application of nanofiller to the polymer solution with subsequent removal of the solvent. The second method is the dispersion polymerization of nanofiller in the monomer. The last one is the application of nanofiller in the dispersion of ethanol into the polymer melt. The experimental part deals with the preparation of foils for characterization of rheological properties of nanocomposites at first. Polystyrene was polymer matrix and selected nanofillers was applied to the polymer solution and then it was removed the solvent. The second method was the preparation of nanocomposites dispersion polymerization of nanofillers in the monomer. The method in-situ preparation of nanocomposite is based on the thermal initiated polymerisation of styrene in the dispersion of nanofillers with the selected type radical initiator. The third proposed method was the application of ethanol dispersion of fillers into the polymer melt in the Brabender mixer.
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The influence of nanoparticles on isothermal crystallization rate of isotactic polypropylene
Miškolci, Michal ; Jančář, Josef (referee) ; Bálková, Radka (advisor)
This diploma thesis deals with the study of isothermal crystallization of nanocomposite materials based on isotactic polypropylene (iPP) and nanosilica, depending on the volume fraction (0, 2, 4 and 6 %) and type of silica and the crystallization temperature. Fumed silica and four types of silica with different surface treatment were used as filler. The crystallization performed at temperatures 136, 138, 140 and 142 °C has been studied in-situ using polarized optical microscope and the crystallization rate was evaluated from the growing radius of spherulites. It can be stated that particles of silica have been inbuilt into the spherulites due to the linear growth of spherulites of all composite materials. The most significant increase of the crystallization rate of iPP was caused by fumed silica, the most significant decrease was caused by silica TS-720 at volume fraction 4 %. The crystallization rate (G) has been slightly increased with the increasing volume fraction of filler at 136 °C, the G slightly decreased at 138 °C and there was no trend of G for two higher temperatures. Also, it was not possible to exactly evaluate the influence of the surface treatments. The reason is the most probably uneven (non-homogenous) distribution of nanosilica as revealed thermogravimetric analysis. The crystallization kinetics was evaluated according to the Lauritzen-Hoffmann theory. The morphological part of the study showed that iPP was in ? and ß-structure and spherulites of ? phase were of the type I, II and mixed.
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Study of electric properties of nanocomposit material
Ovsík, Jiří ; Rozsívalová, Zdenka (referee) ; Polsterová, Helena (advisor)
This work deals with the electrical properties of nanocomposite materials. Samples for the experiment are made of epoxy resin as matrix and titanium dioxide TiO2 as nanofillers in varying percentage performance. Measurements are temperature dependent components of the permittivity, dissipation factor and resistivity. Furthermore, the internal resistivity is observed with regard to the percentage performance of a sample of nanoparticles.
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Study of electrical properties of nanocomposites
Ovsík, Jiří ; Rozsívalová, Zdenka (referee) ; Polsterová, Helena (advisor)
The present work deals with the electrical properties of nanocomposite materials. Samples for the experiment are made of epoxy resin as a matrix and oxides TiO2, Al2O3, WO3, SiO2 as nanofillers in 0.5 and 1 percent performance. The experimental samples are measured in temperature and frequency dependence of relative permittivity, dissipation factor, rezistivity and are broken down by the influence of filler on the electrical properties of the polymer. Attention is also paid to the mechanical properties of nanocomposites.
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