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The correlation of the molecular structure of polyolefins with environmental stress cracking resistance
Thesis (MSc (Chemistry and Polymer Science))--University of Stellenbosch, 2006.
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| Other Authors: | |
| Format: | Thesis |
| Language: | English |
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Stellenbosch : University of Stellenbosch
2008
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| _version_ | 1867614037450162176 |
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| access_status_str | Open Access |
| author | Shebani, Anour Nasser |
| author2 | Van Reenen, Albert J. |
| author_browse | Shebani, Anour Nasser Van Reenen, Albert J. |
| author_facet | Van Reenen, Albert J. Shebani, Anour Nasser |
| author_sort | Shebani, Anour Nasser |
| collection | Thesis |
| dc_rights_str_mv | University of Stellenbosch |
| description | Thesis (MSc (Chemistry and Polymer Science))--University of Stellenbosch, 2006. |
| format | Thesis |
| id | oai:scholar.sun.ac.za:10019.1/2751 |
| institution | Stellenbosch University (South Africa) |
| language | English |
| last_indexed | 2026-06-10T12:45:40.057Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from SUNScholar — Stellenbosch University Repository |
| publishDate | 2008 |
| publishDateRange | 2008 |
| publishDateSort | 2008 |
| publisher | Stellenbosch : University of Stellenbosch |
| publisherStr | Stellenbosch : University of Stellenbosch |
| record_format | dspace |
| source_str | SUNScholar — Stellenbosch University Repository |
| spelling | oai:scholar.sun.ac.za:10019.1/2751 The correlation of the molecular structure of polyolefins with environmental stress cracking resistance Shebani, Anour Nasser Van Reenen, Albert J. University of Stellenbosch. Faculty of Science. Dept. of Chemistry and Polymer Science. Environmental stress cracking (ESR) Impact polypropylene copolymer Environmental stress cracking resistance (ESCR) Dissertations -- Polymer science Theses -- Polymer science Chemistry and Polymer Science Thesis (MSc (Chemistry and Polymer Science))--University of Stellenbosch, 2006. This study concerns the phenomenon of environmental stress cracking resistance (ESCR) in three impact polypropylene copolymers (IPPCs). The main purpose was to correlate the ESCR with their properties such as microstructure, molecular weight (MW), molecular weight distribution (MWD), crystallinity and morphology. Initially the selection of a suitable test method and an active stress cracking agent (SCA) were the preliminary concerns. The Bell telephone test was used to evaluate SCAs, while a published procedure for determining ESCR of ethylene based plastics was adapted for the purpose of this study. Isopropanol was selected as SCA. Polymers were fully characterized by FTIR, 13C NMR, DSC and high temperature GPC. Optical microscopy was used to investigate craze formation and crack growth, and scanning electron microscopy (SEM) was used to study the morphology of the polymers. Since IPPCs are known to have multi-fraction copolymeric structures and each of these fractions has significantly different average properties, fractions were selectively removed from the materials, either by solvent extraction at room temperature, or by TREF fractionation. The effect of removing these fractions on the ESCR was determined. The effect of the molecular composition of the three IPPCs on the ESCR of these materials, as well as the effect of the removal of the selected molecular fractions on the ESCR, morphology and molecular characteristics are discussed and compared. Conclusions are drawn as to the factors controlling ESCR in these materials. 2008-07-29T09:11:08Z 2010-06-01T08:57:26Z 2008-07-29T09:11:08Z 2010-06-01T08:57:26Z 2006-12 Thesis http://hdl.handle.net/10019.1/2751 en University of Stellenbosch application/pdf Stellenbosch : University of Stellenbosch |
| spellingShingle | Environmental stress cracking (ESR) Impact polypropylene copolymer Environmental stress cracking resistance (ESCR) Dissertations -- Polymer science Theses -- Polymer science Chemistry and Polymer Science Shebani, Anour Nasser The correlation of the molecular structure of polyolefins with environmental stress cracking resistance |
| title | The correlation of the molecular structure of polyolefins with environmental stress cracking resistance |
| title_full | The correlation of the molecular structure of polyolefins with environmental stress cracking resistance |
| title_fullStr | The correlation of the molecular structure of polyolefins with environmental stress cracking resistance |
| title_full_unstemmed | The correlation of the molecular structure of polyolefins with environmental stress cracking resistance |
| title_short | The correlation of the molecular structure of polyolefins with environmental stress cracking resistance |
| title_sort | correlation of the molecular structure of polyolefins with environmental stress cracking resistance |
| topic | Environmental stress cracking (ESR) Impact polypropylene copolymer Environmental stress cracking resistance (ESCR) Dissertations -- Polymer science Theses -- Polymer science Chemistry and Polymer Science |
| url | http://hdl.handle.net/10019.1/2751 |
| work_keys_str_mv | AT shebanianournasser thecorrelationofthemolecularstructureofpolyolefinswithenvironmentalstresscrackingresistance AT shebanianournasser correlationofthemolecularstructureofpolyolefinswithenvironmentalstresscrackingresistance |