magistrsko delo magistrskega študijskega programa II. stopnje Strojništvo
Peter Tomšič (Author), Lidija Slemenik Perše (Mentor)

Abstract

Izdelke iz polimernih materialov izdelujemo z različnimi tehnološkimi procesi, kot so brizganje, ekstrudiranje, termoformiranje in pihanje. Končne lastnosti izdelka, proizvedenega iz delno kristaliničnih polimerov, so v veliki meri odvisne od notranje strukture, ki se formira med predelovalnim procesom. Nanjo vplivamo s številnimi parametri. Eden pomembnejših je hitrost, s katero oblikovan izdelek shladimo. V eksperimentalnem delu magistrske naloge smo raziskovali, kako hitrost ohlajanja vpliva na reološke, termične in morfološke lastnosti polietilena nizke gostote (LDPE) in polietilena visoke gostote (HDPE). Za izbrana materiala smo s pomočjo diferenčne dinamične kalorimetrije (DSC) določili vpliv različnih hitrosti ohlajanja na temperature faznih sprememb in izračunali delež kristalne strukture za posamezno hitrost ohlajanja. Pri enakih temperaturnih pogojih smo izvedli reološke meritve, ki so nam pomagale razumeti vpliv hitrosti temperaturnih sprememb na reološke lastnosti. Z optičnim polarizacijskim mikroskopom pa smo opazovali, kako se pri tem spreminja morfologija materialov.

Keywords

magistrske naloge;LDPE;HDPE;diferencialna dinamična kalorimetrija;reologija;kristaliničnost;viskoznost;morfologija;

Data

Language: Slovenian
Year of publishing:
Typology: 2.09 - Master's Thesis
Organization: UL FS - Faculty of Mechanical Engineering
Publisher: [P. Tomšič]
UDC: 536.54:678.675(043.2)
COBISS: 120246019 Link will open in a new window
Views: 265
Downloads: 30
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Other data

Secondary language: English
Secondary title: The effect of cooling rate on rheological, thermal and morphological properties of low- and high-density polyethylene
Secondary abstract: Plastic products are prepared by various technological processes, such as injection moulding, extrusion, thermoforming and blowing. Final properties of the semi-crystalline polymer product largely depend on the internal structure formed during the manufacturing process. The formation of the internal crystalline structure depends on various parameters. One of the most important ones is the cooling rate. In the experimental part of the master's thesis, the research was focused on the effect of cooling rate on the rheological, thermal and morphological properties of low-density polyethylene (LDPE) and high-density polyethylene (HDPE). Differential scanning calorimetry (DSC) was used to determine the influence of different cooling rates on phase transitions temperatures. Moreover, for each cooling rate, the percentage of the crystal structure – degree of crystallinity was calculated. Rheological measurements were performed at the same temperature conditions and the results were used to understand the impact of the rate of temperature changes on rheological properties. Finally, the changes in morphology were followed by using an optical polarizing microscope.
Secondary keywords: master thesis;differential scanning calorimetry;rheology;crystallinity;viscosity;morphology;
Type (COBISS): Master's thesis/paper
Study programme: 0
Embargo end date (OpenAIRE): 1970-01-01
Thesis comment: Univ. Ljubljana, Fak. za strojništvo
Pages: XX, [70] str.
ID: 16345602
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