Developing marker technologies to probe complex polymers and products

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dc.contributor.advisorVan Reenen, Alberten_ZA
dc.contributor.advisorLutz, Marietjieen_ZA
dc.contributor.authorLiprini, Marehette Suzanneen_ZA
dc.contributor.otherStellenbosch University. Faculty of Science. Dept. of Chemistry and Polymer Science.en_ZA
dc.date.accessioned2022-11-15T21:07:13Zen_ZA
dc.date.accessioned2023-01-16T12:51:54Zen_ZA
dc.date.available2022-11-15T21:07:13Zen_ZA
dc.date.available2023-01-16T12:51:54Zen_ZA
dc.date.issued2022-11en_ZA
dc.descriptionThesis (PhD) -- Stellenbosch University, 2022.en_ZA
dc.description.abstractENGLISH ABSTRACT: Fluorescent imaging has proven to be a valuable tool across a wide variety of applications. It can help with detecting, locating and observing the interactions between different molecules. This study used fluorescence to evaluate interactions, provide detection and trace different components within complex polymer systems. Cellulose nanowhiskers (CNW) were isolated and characterized, then labelled using fluorescent labelling with fluorescein 5(6)-isothiocyante (FITC) and rhodamine B (RhB). The attachment of the fluorescent dyes was easily observed with fluorescence microscopy. Fluorescently labelled cellulose nanowhiskers (CNW) were incorporated into different crystalline fractions of two different types of polypropylene impact copolymers (CMR 648 and CMR 348). This part of the study focused on the visually assessing the interactions between the different crystalline fractions within polypropylene impact copolymers. The different fractions of the copolymers were first evaluated in the form of solvent-cast films. The solvent-cast films showed strong associations between the 30 oC fraction and the 60 oC fraction, as well as between the 60 oC fraction and the 80 oC fraction. The fluorescent images showed no strong association between the 30 oC fraction and the 80 oC fraction in the absence of the 60 oC fraction. The fraction interactions were also evaluated after mechanical agitation in the melt, followed by injection moulding. The injection-moulded samples showed the same interactions visually as observed with the solvent-cast films. The visual assessment after extracting the labelled 30 oC fraction and 60 oC fraction also showed that the labelled CNW did not migrate out of the fractions into which they were incorporated. The next section of this study focused on the detection of fluorescently labelled markers within paint samples. CNW labelled with fluorescent dyes were incorporated into two types of paint. The paint films were evaluated with confocal fluorescence microscopy and the different paint samples could be identified. The fluorescent markers could still be detected within the paint films even after accelerated weather testing by implementing confocal fluorescence microscopy (CFM), lambda scanning, and unmixing. The last part of the study focused on the release of ethyl formate from different polymer films of polylactic acid (PLA) and polyethylene glycol (PEG). The intrinsic fluorescence associated with the ethyl formate precursor, PLA and PEG was used to track the release of the ethyl formate after exposure to humidity and humidity with citric acid. The release could easily be tracked visually with CFM.en_ZA
dc.description.abstractAFRIKAANS OPSOMMING: Die gebruik van fluoresserende middels het bewys dat dit 'n baie waardevolle hulpmiddel kan wees in 'n wye reeks van toepassings. Dit kan bydra tot die naspeuring, opsporing en evaluering van interaksies tussen verskillende molekules. Hierdie studie het gebruik gemaak van fluoressensie as hulpmiddel om effektiewelik interaksies, identifikasie en die vrystelling van verskillende komponente binne komplekse polimeerstelsels te evalueer. Sellulose nanovesels (SNV) was eerstens geïsoleer en gekarakteriseer. Daarna was die SNV gemerk met fluoresserende merkers. Die SNV is gemerk met fluoressien 5(6)-isotiosianaat (FITC) en rhodamien B (RhB) onderskeidelik. Die aanhegting van die fluoresserende merkers was maklik waargeneem met behulp van fluoressensie mikroskopie. Die sellulose nanovesels (SNV) gemerk by wyse van fluoressensie is in kristallyne fraksies van twee verskillende tipes polipropileen impak kopolimere (CMR 648 en CMR 348) geïnkorporeer. Hierdie deel van die studie het gefokus op die visuele assessering van die interaksies tussen die verskillende kristallyne fraksies binne polipropileen impak kopolimere. Die verskillende fraksies van die kopolimere is eers in die vorm van films geëvalueer. Die films het sterk assosiasies tussen die 30 oC fraksie en die 60 oC fraksie sowel as tussen die 60 oC fraksie en die 80 oC fraksie getoon. Die fluoressensie mikroskopie fotos het geen sterk assosiasies tussen die 30 oC fraksie en die 80 oC fraksie in die afwesigheid van die 60 oC fraksie getoon nie. Die fraksie interaksies was ook geëvalueer na meganiese roering in die verhitte toestand gevolg deur spuitgiet. Die spuitgiet monsters het dieselfde interaksies visueel getoon as wat waargeneem was gedurende die evaluasie van die films. Die visuele assessering na die onttrekking van die gemerkte 30 oC fraksie en 60 oC fraksie onderskeidelik, het ook getoon dat die gemerkte SNV nie uit die fraksies waarin hulle geïnkorporeer was migreer het nie. Die volgende afdeling van hierdie studie het gefokus op die opsporing van fluoresserende merkers binne verfmonsters. Sellulose nanovesels wat gemerk was met fluoresserende kleurstowwe was in twee tipes verf geïnkorporeer. Die verf films was met gefokusde fluoressensie mikroskopie (GFM) geëvalueer en die verskillende verf monsters kon geïdentifiseer word. Die opsporing van die fluoresserende merkers kon steeds binne die verf films opgespoor word, selfs na versnelde weertoetsing met behulp van GFM gekombineerd met lambda-skandering. Die laaste deel van die studie het gefokus op die vrystelling van etielformaat uit verskillende polimeerfilms wat bestaan het uit poli(melksuur) (PLA) en poli(ëtileenglikol) (PEG). Die intrinsieke fluoressensie wat geassosieer word met die etielmetanoaatvoorloper, die PLA en die PEG onderskeidelik, was gebruik om die vrystelling van die etielmetanoaat na blootstelling aan humiditeit en humiditeit met sitroensuur te monitor. Die vrystelling kon maklik visueel gevolg word met GFM.en_ZA
dc.description.versionDoctoralen_ZA
dc.format.extentxxiii, 150 pages : illustrationsen_ZA
dc.identifier.urihttp://hdl.handle.net/10019.1/126135en_ZA
dc.language.isoen_ZAen_ZA
dc.publisherStellenbosch : Stellenbosch Universityen_ZA
dc.subjectConfocal fluorescence microscopyen_ZA
dc.subjectFluorescent polymersen_ZA
dc.subjectPolypropyleneen_ZA
dc.subjectCellulose nanocrystalsen_ZA
dc.subjectPolypropylene impact copolymersen_ZA
dc.subjectEthyl formateen_ZA
dc.subjectUCTDen_ZA
dc.titleDeveloping marker technologies to probe complex polymers and productsen_ZA
dc.typeThesisen_ZA
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Doctoral Degrees (Chemistry and Polymer Science)