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Production of composite materials using vacuum infusion
Ciran, Adam ; Gregor, Lukáš (referee) ; Zouhar, Jan (advisor)
The theoretical part of the bachelor thesis deals with the definition of composite material, then the division of the most used fabric reinforcements and matrices, with a focus on reinforcements made of glass and carbon fiber and flax fiber. It then discusses vacuum infusion techniques, their description and applications. In the practical part, emphasis is placed on the fabrication of specimens using vacuum infusion technology of carbon fiber, glass fiber and flax using an epoxy matrix. The last part is the evaluation of the fabricated samples.
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Surface modification of glass fibers for polymer composites
Knob, Antonín ; Marek,, Aleš (referee) ; Burša, Jiří (referee) ; Čech, Vladimír (advisor)
The doctoral thesis is aimed at preparation of glass fiber reinforced polymer composites with controlled interphase formed by plasma-polymerized tetravinylsilane and tetravinylsilane/oxygen thin films. The thin polymer films of specific physico-chemical properties and thickness were deposited to improve interfacial adhesion of glass fiber/polyester composites. The fiber surface modification was performed by using plasma enhanced chemical vapor deposition in low-temperature RF plasma operating in an various effective power range and different treatment time. Test results were examined in relation to the interlayer thickness and different treatment conditions. The prepared interlayers were analyzed to evaluate physico-chemical composition and properties (XPS, RBS, ERDA, FTIR and spectroscopic elipsometry). Selected mechanical properties were evaluated by AFM. Mechanical response of plasma interlayers was evaluated by short beam shear test and direct method of testing the interfacial shear strength using microindentation. The interphase shear failure was controlled by the shear strength at the interlayer/fiber interface as follows from experimental and model data.
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Properties of reinforcing glass-fiber geogrids in pavement structure
Maláník, Stanislav ; Šperka, Pavel (referee) ; Dašek, Ondřej (advisor)
Bachelor's thesis deals with the use of glass fiber reinforcement geogrids in road construction. Bachelor's thesis is focused on basic knowledge of reinforcing geosynthetics and on summary of existing regulations concerning the use of geogrids in roadway. The influence of the construction of the road layers on the change of the geogrid properties is evaluated by suitable tests. In particular, the effects of the impact of the movement of the construction technique on the geogrid and the effects of the compaction of the overlying layer on the geogrid properties were simulated in the laboratory.
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Surface modification of glass fibers using plasma nanotechnology
Sedlák, Filip ; Knob, Antonín (referee) ; Čech, Vladimír (advisor)
Diploma thesis is aimed at deposition of thin films on glass fibers using plasma-enhanced chemical vapor deposition from tetravinylsilane as a monomer. Such surface modified glass fibers were used as reinforcements for fabrication of polymer composites with unsaturated polyester resin as a matrix. Chemical and optical properties of prepared thin films were characterized using infared spectroscopy and spectroscopic ellipsometry. An influence of deposited thin films on the shear strength of composite material was observed using short-beam shear test.
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Technology of manufacturing of carbon fibre composites by hot forming
Přikryl, Pavel ; Slaný, Martin (referee) ; Zouhar, Jan (advisor)
This master’s thesis deals with the composite materials and especially aims on the carbon and glass fiber composites. It points out different composition types and manufacturing methods which reflect in the different mechanical properties, final quality of the manufactured part and also in the manufacturing time. The practical part includes two particular manufacturing methods using prepregs, one cured in an autoclave and one by hot compression moulding.
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Plasma surface modification of glass fibers and its optimization
Širjovová, Veronika ; Knob, Antonín (referee) ; Čech, Vladimír (advisor)
Diploma thesis deals with glass fiber surface modification using plasma-enhanced chemical vapor deposition in order to prepare functional interface that enhances the properties of polymer composites. The effect of deposition conditions on shear strength was observed with respect to the chemical composition of the deposited film. Thin films were deposited on planar substrates and fibers using monomer tetravinylsilane in a mixture with oxygen at selected power of plasma discharge. Chemical composition of prepared material was analyzed by infrared spectroscopy. Planar substrate film adhesion was measured using the scratch test. The composite sample was prepared by embedding the surface modified fibers in unsaturated polyester resin, followed by the curing process. The cured composite sample underwent the short beam shear test.
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Fiber reinforcements for polymer composites
Knob, Antonín ; Grégr, Jan (referee) ; Čech, Vladimír (advisor)
The bachelor thesis is concerned with an influence of surface modification of fibrous reinforcements on mechanical properties at the fiber-matrix interface in fiber-reinforced polymer composites. Polyester resin was used as a matrix, glass and carbon fibers were the reinforcements. The composite sample consisted of polymer matrix in a form of cylindrical body placed on a bundle of fibers. Untreated fibers and fibers with a commercial sizing were used for fabrication of composite samples. The tensile test using a materials testing machine (Zwick) was employed to evaluate adhesion at the fiber-matrix interface.
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Asphalt layers with reinforcing glass-fiber geogrids
Sachr, Jiří ; Bohuš,, Štěpán (referee) ; Dašek, Ondřej (advisor)
This diploma thesis deals with the use of glass fiber geogrids and geocomposites in road construction. The reinforcement elements are inserted between the wearing and binder asphalt layer. This diploma thesis summarizes the knowledge connected with reinforcing of asphalt roads using glass fiber. It examines the effect of reinforcing fiberglass elements on the resistance of asphalt layers loaded with traffic. At the same time, it deals with the application of a various amount of tack coat and subsequent behavior of the asphalt layers. In this work, laboratory tests of bond strength between layers on cores and four-point bending were performed.
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