Thesis (MSc)--Stellenbosch University, 2014. / ENGLISH ABSTRACT: Novel poly(methacrylic acid)-graft-poly(dimethylsiloxane) copolymers were synthesised by
conventional free radical reactions using a poly(dimethylsiloxane) macromonomer. The
polymers were electrospun to investigate how the fibre morphology can be modified by
manipulating the electrospinning solution parameters, and to determine the possibility of using
the polymers as new materials for the production of polymer nanofibre hydrogels. The
electrospinning solution parameters were varied by electrospinning the highly amphiphilic
copolymers in solvents with variable solvent qualities. Scanning Electron Microscopy (SEM) and
Field Emission Scanning Electron Microscopy (FE–SEM) was used to investigate the fibre
morphology. Internal morphology was studied using a freeze fracture technique prior to FE-SEM
imaging. It is revealed that the polymers in this study does not form any fine structure or pores
even when self-assembled structures are present in the solution. Attempts were made to
visualise any self-assembled structures of films produced from dilute solutions using TEM.
Further studies included investigating the fibres properties, primarily with regards to their rate
and extent of moisture and water uptake. The fibres showed hydrogel behaviour and the PDMS
content were found to have an impact on the hydrogel stability. Post electrospinning crosslinking
of the nanofibres was also explored. / AFRIKAANSE OPSOMMING: Unieke ent-kopolimere wat bestaan uit poli(metielakrielsuur) (PMAS) en poli(dimetielsiloksaan)
(PDMS) is gesintetiseer deur middel van 'n “ent-deur” vryeradikaalkopolimerisasie. 'n PDMS
makromonomeer is vir hierdie doel gebruik. Die polimere is geëlektrospin om vesels te vorm.
Die doel was om die invloed van verkillende strukture in oplossing op die veselmorfologie te
bepaal. Die moontlikheid om hierdie nanovesels as gels te gebruik is ook ondersoek. Die
amfifiliese kopolimere is geëlektrospin uit die oplossing waarin dit wisselende oplosbaarheid
toon. Skandeer elektron mikroskopie (SEM) is gebruik om die morfologie te ondersoek. Die
interne morfologie van die vesels is ondersoek deur die vesels te vries en in die gevriesde
toestand te breek. Die studie het getoon dat geen strukture op, of binne, die vesels vorm nie,
selfs al moes daar assosiasie tussen segmente van die polimere gewees het. Hierdie tipe
assosiasies sou strukture in die oplossing tot gevolg gehad het. 'n Poging is aangewend om die
strukture in oplossing te visualiseer deur transmissie elektron mikroskopie (TEM) van dun films
te ondersoek. Films is vanaf verdunde oplossings gevorm. Ander studies het ingesluit om die
eienskappe van die vesels te ondersoek, met die fokus op hoeveel en hoe vinnig die vesels
waterdamp en water kon absorbeer. Die vesels het soos 'n gel reageer. Hierdie gedrag is
beïnvloed deur die hoeveelheid PDMS wat 'n definitiewe invloed op die stabiliteit van die gel
gehad het. Kruisverbindings van die vesels, nadat dit geëlektrospin is, is ook ondersoek.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:sun/oai:scholar.sun.ac.za:10019.1/86620 |
| Date | 04 1900 |
| Creators | Meltz, Freda-Jean |
| Contributors | Mallon, Peter, Klumperman, Bert, Stellenbosch University. Faculty of Science. Dept. of Chemistry and Polymer Science. |
| Publisher | Stellenbosch : Stellenbosch University |
| Source Sets | South African National ETD Portal |
| Language | en_ZA |
| Detected Language | Unknown |
| Type | Thesis |
| Format | xiii, [124] p. : ill. |
| Rights | Stellenbosch University |
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