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Functionalization of Polypropylene by Grafting
Kelíšek, Petr ; Sadílek, Jiří (referee) ; Petrůj, Jaroslav (advisor)
This bachelor thesis deals with the study of functionalization of polypropylene by grafting. The theoretical part summarizes current knowledge about the properties of polypropylene, polylactic acid, radical grafting, factors influencing the properties of such functionalized polymer and modification of immiscible polymers by the aid of compatibilizer. In the experimental part, samples of polypropylene grafted with polylactic acid, and blends of polypropylene with polylactic acid were prepared on an internal mixer under different conditions. Temperature and torque were monitored during the mixing. Created materials were evaluated by comparing their base properties (tensile strength, melt flox index).
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Study of relation between conditions of the test FNCT (Full Notched Creep) and the rate of crack grow SCG (Slow Crack Growth) for evaluating HDPE cut growth resistance
Porubský, Tomáš ; Sadílek, Jiří (referee) ; Petrůj, Jaroslav (advisor)
Theoretical part of this thesis presents summary of material and testing parameters which influence SCG and consequently the duration of the FNCT test. The experimental part focuses on modification of testing conditions of FNCT test in order to minimize the test time. FNCT tests were performed for four types of surfactants: Arkopal N110, Sodium dodecylbenzensulfonate (NaDBS), Disponil LDBS55 and Simulsol SL8. The most pronounced accelerating effect was observed for NaDBS surfactant, which in comparsion with commonly used Arkopal N110 doubled the test speed at the same concentration (11 %) and other test conditions. The accelerating effect of NaDBS was also observed for two different PE grades: Liten VB85 and VL 20N. Under the test conditions 80 °C and 4 MPa, 5% NaDBS water solution caused for VL 20N almost 12,5-fold acceleration compared to conventional 2% Arkopal N110 and almost 8,5-fold acceleration for VB 85. The correlation between wettability of surfactant solution and FNCT time to fracture was found.
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The Effect of Temperature Annealing on Structure-Property Relationship of Oriented Polypropylene
Sadílek, Jiří ; Jančář, Josef (referee) ; Kohout,, Jan (referee) ; Hell,, Jaroslav (referee) ; Kučera, Jaroslav (advisor)
The aim of this work is to study the effect of thermal history to structure and properties not only of oriented polypropylene monofilaments with different orientation but of course of isotropic non-oriented polypropylene. Term thermal history includes thermal regimes from alpha relaxation temperature (T?) to melting temperature (Tm). This work consists of three parts. The changes of dynamic mechanical properties, strength, deformation and tensile modulus of polypropylene samples according to annealing temperature (Ta) are described in the first part of this work. In the second part, the changes of crystal phase are observed. Preferentially, calorimetric behaviour (DSC), changes of crystal dimensions and orientation function of crystal phase (X-ray) are observed. Measured values from the first and the second part of this work were used for calculation of total orientation function of PP samples. Rheological measurements are shown in the third part of this thesis. Rheological measurements consist of short isothermal creep, shrinkage of free tapes and static deformation at higher temperatures. Measured rheological values were performed using rheological models. Using these models characteristics of entropic spring, instantaneous elasticity and viscosity and tendency to get to state of ease were calculated.
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Legal issues of tax rates
Sadílek, Jiří ; Bakeš, Milan (advisor) ; Karfíková, Marie (referee)
Tax rate problems The subject of the graduation thesis is legal problems of tax rate. The aim of this thesis is description and estimation of the flat tax rate and states, where is established. First of all I define the basic kinds of tax systems - the tax system with one tax rate, the progressive tax system and the flat tax system. Further I deal with the principles and elements of the flat tax rate as interpreted by American economists Robert E. Hall and Alvin Rabushka who are generally acknowledged as fathers of the flat tax rate. Their concept results from three fundamentals - simplicity, equity and efficiency. Hall and Rabushka define the flat tax rate as a tax system with a constant tax rate and minimal tax allowances but it is necessary point out that their flat tax is determined only for income tax - the individual income tax and the business tax. Second I description and judge the most significant arguments for and contra the flat tax rate. The frequently used arguments in favour of the flat tax rate are that the flat tax offers simpler and more effective tax system, refuses double taxation or that motivates more to economic activity. On the contrary critics say that this tax system is unfair because is advantage only for rich people and reduces budget revenues. In the next chapter I analyze and...
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Functionalization of Polypropylene by Grafting
Kelíšek, Petr ; Sadílek, Jiří (referee) ; Petrůj, Jaroslav (advisor)
This bachelor thesis deals with the study of functionalization of polypropylene by grafting. The theoretical part summarizes current knowledge about the properties of polypropylene, polylactic acid, radical grafting, factors influencing the properties of such functionalized polymer and modification of immiscible polymers by the aid of compatibilizer. In the experimental part, samples of polypropylene grafted with polylactic acid, and blends of polypropylene with polylactic acid were prepared on an internal mixer under different conditions. Temperature and torque were monitored during the mixing. Created materials were evaluated by comparing their base properties (tensile strength, melt flox index).
|
|
|
Legal issues of tax rates
Sadílek, Jiří ; Bakeš, Milan (advisor) ; Karfíková, Marie (referee)
Tax rate problems The subject of the graduation thesis is legal problems of tax rate. The aim of this thesis is description and estimation of the flat tax rate and states, where is established. First of all I define the basic kinds of tax systems - the tax system with one tax rate, the progressive tax system and the flat tax system. Further I deal with the principles and elements of the flat tax rate as interpreted by American economists Robert E. Hall and Alvin Rabushka who are generally acknowledged as fathers of the flat tax rate. Their concept results from three fundamentals - simplicity, equity and efficiency. Hall and Rabushka define the flat tax rate as a tax system with a constant tax rate and minimal tax allowances but it is necessary point out that their flat tax is determined only for income tax - the individual income tax and the business tax. Second I description and judge the most significant arguments for and contra the flat tax rate. The frequently used arguments in favour of the flat tax rate are that the flat tax offers simpler and more effective tax system, refuses double taxation or that motivates more to economic activity. On the contrary critics say that this tax system is unfair because is advantage only for rich people and reduces budget revenues. In the next chapter I analyze and...
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The Effect of Temperature Annealing on Structure-Property Relationship of Oriented Polypropylene
Sadílek, Jiří ; Jančář, Josef (referee) ; Kohout,, Jan (referee) ; Hell,, Jaroslav (referee) ; Kučera, Jaroslav (advisor)
The aim of this work is to study the effect of thermal history to structure and properties not only of oriented polypropylene monofilaments with different orientation but of course of isotropic non-oriented polypropylene. Term thermal history includes thermal regimes from alpha relaxation temperature (T?) to melting temperature (Tm). This work consists of three parts. The changes of dynamic mechanical properties, strength, deformation and tensile modulus of polypropylene samples according to annealing temperature (Ta) are described in the first part of this work. In the second part, the changes of crystal phase are observed. Preferentially, calorimetric behaviour (DSC), changes of crystal dimensions and orientation function of crystal phase (X-ray) are observed. Measured values from the first and the second part of this work were used for calculation of total orientation function of PP samples. Rheological measurements are shown in the third part of this thesis. Rheological measurements consist of short isothermal creep, shrinkage of free tapes and static deformation at higher temperatures. Measured rheological values were performed using rheological models. Using these models characteristics of entropic spring, instantaneous elasticity and viscosity and tendency to get to state of ease were calculated.
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|
|
Study of relation between conditions of the test FNCT (Full Notched Creep) and the rate of crack grow SCG (Slow Crack Growth) for evaluating HDPE cut growth resistance
Porubský, Tomáš ; Sadílek, Jiří (referee) ; Petrůj, Jaroslav (advisor)
Theoretical part of this thesis presents summary of material and testing parameters which influence SCG and consequently the duration of the FNCT test. The experimental part focuses on modification of testing conditions of FNCT test in order to minimize the test time. FNCT tests were performed for four types of surfactants: Arkopal N110, Sodium dodecylbenzensulfonate (NaDBS), Disponil LDBS55 and Simulsol SL8. The most pronounced accelerating effect was observed for NaDBS surfactant, which in comparsion with commonly used Arkopal N110 doubled the test speed at the same concentration (11 %) and other test conditions. The accelerating effect of NaDBS was also observed for two different PE grades: Liten VB85 and VL 20N. Under the test conditions 80 °C and 4 MPa, 5% NaDBS water solution caused for VL 20N almost 12,5-fold acceleration compared to conventional 2% Arkopal N110 and almost 8,5-fold acceleration for VB 85. The correlation between wettability of surfactant solution and FNCT time to fracture was found.
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