Full Text Available
Note: Clicking the button above will open the full text document at the original institutional repository in a new window.
Identifying structural defects in end-chain functionalised polyolefins and copolymers from chain walking polymerisation
Thesis (PhD)--Stellenbosch University, 2025.
Saved in:
| Main Author: | |
|---|---|
| Other Authors: | |
| Format: | Thesis |
| Published: |
Stellenbosch : Stellenbosch University
2026
|
| Subjects: | |
| Tags: |
No Tags, Be the first to tag this record!
|
| _version_ | 1867614100533542912 |
|---|---|
| access_status_str | Open Access |
| author | Ndlovu, Petronella Zabesuthu |
| author2 | Lederer, Albena |
| author_browse | Lederer, Albena Ndlovu, Petronella Zabesuthu |
| author_facet | Lederer, Albena Ndlovu, Petronella Zabesuthu |
| author_sort | Ndlovu, Petronella Zabesuthu |
| collection | Thesis |
| dc_rights_str_mv | Stellenbosch University |
| description | Thesis (PhD)--Stellenbosch University, 2025. |
| format | Thesis |
| id | oai:scholar.sun.ac.za:10019.1/134733 |
| institution | Stellenbosch University (South Africa) |
| last_indexed | 2026-06-10T12:46:40.081Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from SUNScholar — Stellenbosch University Repository |
| publishDate | 2026 |
| publishDateRange | 2026 |
| publishDateSort | 2026 |
| publisher | Stellenbosch : Stellenbosch University |
| publisherStr | Stellenbosch : Stellenbosch University |
| record_format | dspace |
| source_str | SUNScholar — Stellenbosch University Repository |
| spelling | oai:scholar.sun.ac.za:10019.1/134733 Identifying structural defects in end-chain functionalised polyolefins and copolymers from chain walking polymerisation Ndlovu, Petronella Zabesuthu Lederer, Albena Stellenbosch University. Faculty of Science. Dept. of Chemistry and Polymer Science. Polyolefins Copolymers -- Analysis Macromolecules -- Structure Polymerase chain reaction Thesis (PhD)--Stellenbosch University, 2025. Ndlovu, P. Z. 2025. Identifying structural defects in end-chain functionalised polyolefins and copolymers from chain walking polymerisation. Unpublished doctoral dissertation. Stellenbosch: Stellenbosch University [online]. Available: https://scholar.sun.ac.za/items/e06c5e5d-f829-4fff-b442-f1f4cfc8e593 ENGLISH ABSTRACT: Most commodity polymers are olefin-based homopolymers or random copolymers, but advanced applications require complex block, star, or graft copolymers for enhanced functionality in blend compatibilization, elastomers, nanolithography, and self-assembled nanoparticles for drug/gene delivery, imaging, and nanoreactors. Polyolefins’ hydrophobicity is ideal for encapsulating hydrophobic molecules, but functionalisation remains challenging. Advances in chain-walking (CW) polymerisation catalysts enable one-pot synthesis of branched, dendritic polyolefins, improving encapsulation efficiency for drug delivery. Combining CW polymerisation with other synthetic techniques like ring-opening polymerisation yields block and graft copolymers with tailored properties. As the synthesis of branched polymers with complex architectures becomes more refined, there has been a growing demand for advanced characterisation methods to correlate polymer structure with performance properties to verify the success of synthesis. This work explores several advanced techniques for the separation and characterisation of these block and graft copolymers with a focus on key parameters such as molar mass, degree of branching, and chemical composition (degree of functionalisation, block length, and graft arms). Part of this study reviews high temperature interaction chromatography of polyolefins with emphasis on solvent and temperature gradient. The first experimental section investigates the characterisation of hydroxyl-functionalised poly(hex-1-ene) from chain walking polymerisation using a Ni (II) catalyst, which serves as a microinitiator for the ring-opening polymerisation of polycaprolactone (PCL) to form a block copolymer (BCP). These functionalised polymers and their resulting BCPs are comprehensively analysed using advanced analytical techniques like multi-detector size exclusion chromatography (SEC) and interaction chromatography (IC), providing detailed insights into the microstructure of the polymers. Hyphenating IC and SEC in a two-dimensional analysis allows for the correlation of chemical composition distribution (CCD) to molar mass distribution (MMD). The study demonstrates the enhanced resolution capabilities of these techniques when applied at both room and high temperatures to help understand the fidelity of the synthesis. In the final part of the study, graft copolymers from chain-walking polyethylene grafted with linear polystyrene arms are characterised for the first time using the same characterisation techniques applied to BCPs. Furthermore, the study introduces the use of multidetector thermal field-flow fractionation (ThFFF), a channel-based separation method, for determining polymer conformations and polystyrene distribution along the polyethylene backbone in a single experiment. This breakthrough enabled a more precise and detailed analysis of the complex polymer structures. This work is particularly novel in its use of liquid chromatography techniques, combined with spectroscopic methods, to analyse copolymers from chain walking polymerisation, establishing notable correlations between the polymer structure and its properties. AFRIKAANSE OPSOMMING: Geen opsomming beskikbaar. Doctoral 2026-01-06T06:37:49Z 2026-01-06T06:37:49Z 2025-12 Thesis https://scholar.sun.ac.za/handle/10019.1/134733 Stellenbosch University xx, 177 pages : illustrations application/pdf Stellenbosch : Stellenbosch University |
| spellingShingle | Polyolefins Copolymers -- Analysis Macromolecules -- Structure Polymerase chain reaction Ndlovu, Petronella Zabesuthu Identifying structural defects in end-chain functionalised polyolefins and copolymers from chain walking polymerisation |
| title | Identifying structural defects in end-chain functionalised polyolefins and copolymers from chain walking polymerisation |
| title_full | Identifying structural defects in end-chain functionalised polyolefins and copolymers from chain walking polymerisation |
| title_fullStr | Identifying structural defects in end-chain functionalised polyolefins and copolymers from chain walking polymerisation |
| title_full_unstemmed | Identifying structural defects in end-chain functionalised polyolefins and copolymers from chain walking polymerisation |
| title_short | Identifying structural defects in end-chain functionalised polyolefins and copolymers from chain walking polymerisation |
| title_sort | identifying structural defects in end chain functionalised polyolefins and copolymers from chain walking polymerisation |
| topic | Polyolefins Copolymers -- Analysis Macromolecules -- Structure Polymerase chain reaction |
| url | https://scholar.sun.ac.za/handle/10019.1/134733 |
| work_keys_str_mv | AT ndlovupetronellazabesuthu identifyingstructuraldefectsinendchainfunctionalisedpolyolefinsandcopolymersfromchainwalkingpolymerisation |