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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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Extension Properties of Graphs and Structures
Klavík, Pavel ; Nešetřil, Jaroslav (advisor) ; Širáň, Jozef (referee) ; Hell, Pavol (referee)
Extension Properties of Graphs and Structures Pavel Klavík The main motivation for graph drawing and geometric representations is finding ways to visualize graphs efficiently to make their structure as understandable as possible. In this thesis, we are concerned with structural properties which are implied for graphs having certain geometric representations. We study two types of geometric representations: inter- section representations in which the vertices are represented by geometric sets while the edges are encoded by their intersections, and planar embeddings of planar graphs which are drawing of graphs into the plane without crossing edges. The existence of geometric representations can be used to deduce additional information about graphs. The main idea of this thesis is to ask what extra information can be deduced from the structure of all possible geometric representations. In Part I, we study the partial representation extension problems for intersection rep- resentations. Aside from the graph, the input also gives a partial representation, which prescribes a representation of an induced subgraph. We ask whether this partial repre- sentation can be extended to a full representation of the input graph without altering the predrawn sets. I introduced this problem in 2010 in my Bachelor's thesis. We...
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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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