National Repository of Grey Literature 102 records found  1 - 10nextend  jump to record: Search took 0.00 seconds. 
Synthesis of Mineral Oils by Oligomeration of 1-alkenes
Porubský, Tomáš ; Kučera, František (referee) ; Petrůj, Jaroslav (advisor)
The theoretical part presents a summary of existing information and procedures for the oligomerization of 1 alkenes. It also introduces suggestion of the new method for preparing poly(1-hexene) by controlled or living polymerization with nitroxyl radicals. In the experimental part was synthesized oligomer of 1-hexene with DBP or AIBN radical initiators and coordination Ziegler-Natta catalysts, which consisted of TiCl4 and organometallic compounds TIBA or TNHA. GC/MS analysis of the radical polymerization reaction mixture, showed no oligomer formation even after 6 hours. Effect of Ti/Al ratio, temperature and type of organoaluminium compund on conversion and molecular weight were investigated. Reaction products were analyzed by 1H NMR and GC/MS spectrometry. Results showed that the obtained oligomer was a mixture of oligomers with a degree of polymerization 2-9 and average molecular weight of 220-270 g/mol. Monomer conversion reached values of 72 98 %.
Photopolymerization
Kučera, Vladimír ; Petrůj, Jaroslav (referee) ; Kučera, František (advisor)
The bachelor thesis deals with the photochemistry of macromolecular substances, especially with photopolymerization and photocrosslinking reactions. In the theoretical section there is at first a summary of the current knowledge from the area of the general photochemistry and principles of photochemical reactions which are also applied in photopolymerization. There are also both types of photopolymerization analysed – cationic and free-radical, photocrosslinking reactions and photopolymerization applications. In the experimental part, the testing of two fotopolymerization systems was performed. In both of them, styrene was used as a monomer. In one case benzoin was used as a photoinitiator, in the second one there was benzoin ethyl ether used. Furthermore, the photoinitiation ability of these two photoinitiators was compared at the base of conversion and molecular weight of products that were synthetized at different concentrations of photoinitiators and different time periods of irradiation of the mercury lamp.
Creep Behaviour of High-Density Polyethylene (HDPE)
Patzelt, Petr ; Přikryl, Zdeněk (referee) ; Petrůj, Jaroslav (advisor)
The theoretical part of the thesis deals with the summary of material properties and testing parameters that influence SCG process. The experimental part is aimed on the comparison of different condition effects on the process of FNCT and PENT. Chosen temperatures for PENT were 70; 80 and 90 °C and the applied nominal stress 2,0; 2,4 and 2,8 MPa. In the case of FNCT the chosen temperatures were the same and the ligamental stress was 4 MPa for all used environments which were: water, Arkopal N110 solution and Dehyton PL solution. In addition, several experiments were measuered under applied nominal stresses 3; 4; 5; 6; 8 a 10 MPa and at 80 °C in Arkopal N110 solution. The morphology of crack surfaces was studied afterwards. The obtained data were used for evaluaion by a five parameter equation.
Polymerization of Lactides in the Melt
Horkel, Ondřej ; Tomala, Libor (referee) ; Petrůj, Jaroslav (advisor)
This bachelor thesis deals with the problematics of Lactide polymerization in the melt. Theoretical part summarizes properties of lactic acid, lactides and polylactides as well as currently used methods of their preparation. In experimental part, a set of three experiments was designed, namely dependance of viscosity average molecular weight on catalyst concentration, polymerisation temperature and polymerisation time. This was achieved by measuring cinematic viscosity using Ubbelohde viscosimeter. As a result of these experiments, it was found that one of posssible combinations of conditions resulting in high molecular weight polymers is the following: concentration ratio of catalyst towards lactide 110–4, polymerisation teperature 160 °C and polymerisation time 3 hours.
Influence of catalysts on polyurethane formation
Chadima, David ; Petrůj, Jaroslav (referee) ; Kučera, František (advisor)
The bachelor thesis deals with the influence of catalysts on polyurethane formation. The theoretical part includes basic knowledge of polyurethane chemistry complemented by a literature review contains information about catalysis and reaction mechanism of polyurethane formation. In experimental part were studied effects of catalysts N,N,N',N' tetramethylethylenediamine, Stannous octoate, 1,4-Diazabicyclo[2.2.2]octane and Dibutyltin dilaurate at the rate of synthesis of the polyurethane resin. The measurement was based on measuring the time for which the reaction mixture reaches the maximum temperature. Effective concentrations of catalysts use were calculated. By additional measurement was performed simplified calculation of the activation energy for the demonstration of the effect of temperature on the observed reaction.
Preparation and characterization of unsaturated bio-polyester resins
Žůrek, Michal ; Petrůj, Jaroslav (referee) ; Figalla, Silvestr (advisor)
The theoretical part of this work is devoted to the selection of suitable components for synthesis of a branched oligoester and their structural arrangement. Further, oligomers of lactic acid esterified with crotonic acid branched by erythritol or pentaerythritol are discussed. Crosslinking of prepared oligoesters is accomplished by free radical mechanism using vinyl acetate as reactive diluent and 2,2'-azo-bis-isobutyronitrile as initiator. Resin was cured by vinyl acetate in different mass ratios. Results show that there in an optimal ratio for curing between oligoester and reactive diluent. Using less vinyl acetate results in insufficient crosslink density or, on the contrary, using considerable excess of vinyl acetate causes rapid polymerization, that also results in lower density of crosslinking. The crosslink density was determined indirectly by extraction of the soluble part to acetone after curing and drying of the product.
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).
Study of poly(lactic acid) foams preparation
Svatík, Juraj ; Petrůj, Jaroslav (referee) ; Figalla, Silvestr (advisor)
The bachelor thesis focuses on the processing of expanded poly(lactic acid) (PLA) or polylactide and on studying of some of its properties. The theoretical part deals with several ways of processing of PLA, its properties and methods of degradation. Furthermore, this part focuses on various processing methods of expanded PLA and the phenomena affecting the expansion, such as dissolving of gases in PLA. At the end of this part, it focuses on strength properties of PLA foams. The experimental part deals with specific way of processing of expanded PLA; that is dissolving of the physical blowing agent in PLA and subsequent foaming. Specific conditions within the processing of PLA foams are investigated there, such as pressure of gas needed, size of PLA particles. Further, this part focuses on distinct types of PLA foams differing in density or processing temperature. Last, it focuses on strength characteristics of PLA foams depending on their density and processing temperature.
Study of Production and Using Mesolactide
Gažo, Peter ; Porubský, Tomáš (referee) ; Petrůj, Jaroslav (advisor)
This bachelor thesis deals with mesolactide production of D,L-lactic acid. In the theoretical part, it has been processed literature review focused on manufacturing methods of mesolactide,it´s processing and using. In the practical part, it has been investigated conditions linked to the most appropriate production of mesolactide.
Radical Polymerization of Unsaturated Organic Acids and Their Anhydrides
Chladil, Martin ; Kučera, František (referee) ; Petrůj, Jaroslav (advisor)
The aim of the thesis is to elaborate literature survay to the thema, its critical review and evaluating results

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4 Petrůj, Jakub
2 Petrůj, Jan
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