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Effect of catalystic system on the structure of E/P copolymers
Kolomazník, Vít ; Kratochvíla,, Jan (referee) ; CSc, Zdeněk Buráň, (advisor)
Thesis is focused on structural study of ethylene-propylene copolymers (E/P copolymers) produced by gas phase polymerization. Goal of work was to determine the effect of used catalysts on the distribution of ethylene units in the resulting material. Three E/P copolymers were prepared on commercial Ziegler Natta catalysts with diether or phthalate based internal donors. The copolymers were fractionated according crystallization ability and molar mass. Next, the mass content and the distribution of the ethylene units in the copolymer were determined in each fraction by nuclear magnetic resonance (NMR). Together with other structural analytical methods, phthalate internal donor has been found to produce ethylene blocks under certain conditions, while the diether ID lacks this ability.
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Effect of controlled degradation on the structure of high-impact polypropylene
Pragerová, Barbora ; Kratochvíla,, Jan (referee) ; CSc, Zdeněk Buráň, (advisor)
This thesis deals with the effect of controlled degradation on the structure of ethylene-propylene copolymers. The studied samples were produced in reactor as a heterophase mixture of homopolymer PP and~E/P copolymer on Ziegler-Natta catalysts. Two samples were degraded to a higher melt flow index using peroxides. These materials were then compared with reactor-prepared samples of the same melt flow index. In total, six samples of E/P copolymers were investigated, i.e. two series of three comparison samples each. For all samples, the melt flow index and the soluble fraction in xylene were determined (using the standard method according to XS-ISO 16152 and also XS-FIPA). Furthermore, in order to obtain detailed information about the structure of these materials, the granular samples were first subjected to TREF (Temperature rising elution fractionation. Each sample was separated into three fractions for which the molecular weight distribution was then determined by gel permeation chromatography (GPC). Nuclear magnetic resonance C13 NMR provided additional information. Changes in the structure of the E/P copolymers after controlled degradation were evaluated, and these degraded materials were also compared with their reactor equivalents produced directly with a higher melt flow index.
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Effect of controlled degradation on the structure of high-impact polypropylene
Pragerová, Barbora ; Kratochvíla,, Jan (referee) ; CSc, Zdeněk Buráň, (advisor)
This thesis deals with the effect of controlled degradation on the structure of ethylene-propylene copolymers. The studied samples were produced in reactor as a heterophase mixture of homopolymer PP and~E/P copolymer on Ziegler-Natta catalysts. Two samples were degraded to a higher melt flow index using peroxides. These materials were then compared with reactor-prepared samples of the same melt flow index. In total, six samples of E/P copolymers were investigated, i.e. two series of three comparison samples each. For all samples, the melt flow index and the soluble fraction in xylene were determined (using the standard method according to XS-ISO 16152 and also XS-FIPA). Furthermore, in order to obtain detailed information about the structure of these materials, the granular samples were first subjected to TREF (Temperature rising elution fractionation. Each sample was separated into three fractions for which the molecular weight distribution was then determined by gel permeation chromatography (GPC). Nuclear magnetic resonance C13 NMR provided additional information. Changes in the structure of the E/P copolymers after controlled degradation were evaluated, and these degraded materials were also compared with their reactor equivalents produced directly with a higher melt flow index.
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Effect of catalystic system on the structure of E/P copolymers
Kolomazník, Vít ; Kratochvíla,, Jan (referee) ; CSc, Zdeněk Buráň, (advisor)
Thesis is focused on structural study of ethylene-propylene copolymers (E/P copolymers) produced by gas phase polymerization. Goal of work was to determine the effect of used catalysts on the distribution of ethylene units in the resulting material. Three E/P copolymers were prepared on commercial Ziegler Natta catalysts with diether or phthalate based internal donors. The copolymers were fractionated according crystallization ability and molar mass. Next, the mass content and the distribution of the ethylene units in the copolymer were determined in each fraction by nuclear magnetic resonance (NMR). Together with other structural analytical methods, phthalate internal donor has been found to produce ethylene blocks under certain conditions, while the diether ID lacks this ability.
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