The fractionation and characterisation of propylene-ethylene random copolymers

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dc.contributor.advisorVan Reenen, A. J.
dc.contributor.authorHarding, Garethen_ZA
dc.contributor.otherUniversity of Stellenbosch. Faculty of Science. Dept. of Chemistry and Polymer Science.
dc.date.accessioned2008-07-14T12:08:29Zen_ZA
dc.date.accessioned2010-06-01T09:06:53Z
dc.date.available2008-07-14T12:08:29Zen_ZA
dc.date.available2010-06-01T09:06:53Z
dc.date.issued2005-12en_ZA
dc.descriptionThesis (MSc (Chemistry and Polymer Science))--University of Stellenbosch, 2005.
dc.description.abstractThis study involves the fractionation and characterisation of three propyleneethylene random copolymers. The fractionation technique used in the study was temperature rising elution fractionation (TREF). The TREF fractions were subsequently analysed offline by crystallisation analysis fractionation (CRYSTAF), differential scanning calorimetry (DSC), 13C NMR, high-temperature gel-permeation chromatography (HT-GPC), and wide-angle x-ray diffraction (WAXD). The effect of the ethylene comonomer on the crystallisability of the propylene was investigated, along with the effect of the comonomer on the type of crystal phase formed during the crystallisation. The results show that the comonomer inhibits the crystallisation of the copolymer and that as the ethylene content increases, the crystallisation and melting points decrease. It was also shown that the higher the ethylene content, the more of the γ-phase crystal type is formed. The distribution of the comonomer throughout the copolymers was also investigated. The results show that there is an uneven distribution of the comonomer with most of the comonomer accumulating in the amorphous areas, and very little actually being incorporated in the crystalline regions. It was also observed that the fractions eluting at the highest temperatures had considerably higher polydispersities and lower molecular weights than the fractions eluting just before them. The highest temperature fractions also have lower melting and crystallisation temperatures than the preceding fractions. This has been attributed to a nucleation effect by the sand support used during the TREF fractionation.en_ZA
dc.identifier.urihttp://hdl.handle.net/10019.1/3123
dc.language.isoenen_ZA
dc.publisherStellenbosch : University of Stellenbosch
dc.rights.holderUniversity of Stellenbosch
dc.subjectPolypropyleneen_ZA
dc.subjectPolyethyleneen_ZA
dc.subjectPolymers separationen_ZA
dc.subjectPolymers analysisen_ZA
dc.subjectDissertations -- Polymer scienceen_ZA
dc.subjectTheses -- Polymer scienceen_ZA
dc.subject.otherChemistry and Polymer Scienceen_ZA
dc.titleThe fractionation and characterisation of propylene-ethylene random copolymersen_ZA
dc.typeThesisen_ZA
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