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Development of methodology for study of mechanical activation of chemical reactions at phase boundaries
Matoušek, David ; Kalina, Lukáš (referee) ; Šoukal, František (advisor)
This Bachelor thesis deals with impact of mechanochemical activation on a nature of interphase region in macro-defect-free composites (MDF). MDF composites are highly perspective material on a polymer-cement basis. The most significant advantage of this material is high flexural strength (cca 150 MPa). High strength is caused by high-shear mixing of mixture of cement, polymer, water and plasticiser in twin-roll mill. High-shear stress leads to mechanical activation of reactions between cement and polymer and creation of weak or even strong interactions in interphase region. This work aimed on creation of interphase region by contact of surfaces of two moulded tablets – polyvinyl alcohol and monocalcium aluminate. Next step was construction of simple apparatus, able to define the rate of mechanical activation in interphase region. The most important part of this work concentrated on analysis of activated interphase region by XPS.
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Composite cements with heat-convertible polymer - preparation and parameters
Surman, František ; Šiler, Pavel (referee) ; Havlica, Jaromír (advisor)
This bachelor’s thesis deals with the preparation and study of composite material based on thermosetting polymer (phenol resin) and inorganic binder (high alumina cement). Very high mechanical properties, considerable stability to moisture and heat are specific properties of this polymer-cement composite. The special preparation means high-shear mixing, which depends resultant properties of composite to a considerable extent. Theoretical part reveals the reason of high achievements, which are typical for this polymer-cement composite but not for other type of inorganic binder used in this composite. This part furthermore studies chemical and physical processes, which occurs in composite mixture during processing and hardening, environmental durability and general applications of polymer modified cements. Practical part includes the laboratory preparation of phenol resin and the study of flexural strength of composite according to resin content in composite mixture. The flexural strength was measured by universal test machine Zwick Z010. Microstructure of material was observed by optical microscopy.
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Mechanical activation of chemical reactions at interfaces of MDF composites
Matoušek, David ; Másilko, Jiří (referee) ; Šoukal, František (advisor)
The thesis deals with study of mechnochemical activation of chemical reactions at interphase of MDF composites. MDF composites are high-perspective composite materials on polymer-cement base. They excel especially in terms of flexural strengths. High flexural stregth is caused by binding interactions between the polymer and the cement. This interactions arise due to mechanochemical activation of raw material mixture at the stage of production. This work focuses on the creation of artificial cement-polymer interphase by contacting the surfaces of two molded tablets (polyvinyl alcohol and monocalcium aluminate), activation of chemical reactions at interphase by means of specially designed appartus, which achieves good plane-parallelism of activation surfaces and good definability of activation conditions (shear rate, pressure). After experiments under different conditions, the activated surfaces are analyzed by SEM, EDS, XPS and FT-IR.
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Mechanical activation of chemical reactions at interfaces of MDF composites
Matoušek, David ; Másilko, Jiří (referee) ; Šoukal, František (advisor)
The thesis deals with study of mechnochemical activation of chemical reactions at interphase of MDF composites. MDF composites are high-perspective composite materials on polymer-cement base. They excel especially in terms of flexural strengths. High flexural stregth is caused by binding interactions between the polymer and the cement. This interactions arise due to mechanochemical activation of raw material mixture at the stage of production. This work focuses on the creation of artificial cement-polymer interphase by contacting the surfaces of two molded tablets (polyvinyl alcohol and monocalcium aluminate), activation of chemical reactions at interphase by means of specially designed appartus, which achieves good plane-parallelism of activation surfaces and good definability of activation conditions (shear rate, pressure). After experiments under different conditions, the activated surfaces are analyzed by SEM, EDS, XPS and FT-IR.
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Development of methodology for study of mechanical activation of chemical reactions at phase boundaries
Matoušek, David ; Kalina, Lukáš (referee) ; Šoukal, František (advisor)
This Bachelor thesis deals with impact of mechanochemical activation on a nature of interphase region in macro-defect-free composites (MDF). MDF composites are highly perspective material on a polymer-cement basis. The most significant advantage of this material is high flexural strength (cca 150 MPa). High strength is caused by high-shear mixing of mixture of cement, polymer, water and plasticiser in twin-roll mill. High-shear stress leads to mechanical activation of reactions between cement and polymer and creation of weak or even strong interactions in interphase region. This work aimed on creation of interphase region by contact of surfaces of two moulded tablets – polyvinyl alcohol and monocalcium aluminate. Next step was construction of simple apparatus, able to define the rate of mechanical activation in interphase region. The most important part of this work concentrated on analysis of activated interphase region by XPS.
|
|
|
Composite cements with heat-convertible polymer - preparation and parameters
Surman, František ; Šiler, Pavel (referee) ; Havlica, Jaromír (advisor)
This bachelor’s thesis deals with the preparation and study of composite material based on thermosetting polymer (phenol resin) and inorganic binder (high alumina cement). Very high mechanical properties, considerable stability to moisture and heat are specific properties of this polymer-cement composite. The special preparation means high-shear mixing, which depends resultant properties of composite to a considerable extent. Theoretical part reveals the reason of high achievements, which are typical for this polymer-cement composite but not for other type of inorganic binder used in this composite. This part furthermore studies chemical and physical processes, which occurs in composite mixture during processing and hardening, environmental durability and general applications of polymer modified cements. Practical part includes the laboratory preparation of phenol resin and the study of flexural strength of composite according to resin content in composite mixture. The flexural strength was measured by universal test machine Zwick Z010. Microstructure of material was observed by optical microscopy.
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