Thesis (MSc)--University of Stellenbosch, 2005. / ENGLISH ABSTRACT: Chemical and molecular tagging agents have illustrated their diversity in a number of
different applications. One of the most significant applications includes the use of chemical
tagging agents for product registration in industry. Industrial enterprises producing good
products need to ensure product authenticity to prevent duplication through piracy and
unscrupulous industrialists. Fluorescent probes are chemical compounds that satisfy most
of the technical and commercial aspects that are required to be excellent tagging agents.
They are generally quick to synthesize, do not affect the product integrity, display little or
no impact on the uses of the product or the environment and they can be identified by
relatively simple detection procedures. The aim of the present study was to synthesize
fluorescent polymers as tagging agents for the paint industry.
7-Hydroxy-2H-chromen-2-one (A1) and 7-hydroxy-4-methyl-2H-chromen-2-one (B1),
commercially available fluorescent hydroxyl compounds, were selected as the starting
materials. An esterification reaction resulted in the production of 2-oxo-2H-chromen-7-yl
acrylate (A2) and 4-methyl-2-oxo-2H-chromen-7-yl acrylate (B2), which are acrylic-type
monomers that were required for polymerisation. Studies showed that fluorescence was
maintained during the esterification.
Copolymers poly(MMA-co-A2), poly(MMA-co-B2), poly(BA-co-A2) and poly(BA-co-B2),
synthesized via homogeneous free radical initiated copolymerisation, revealed how
copolymer compositions were affected by the feed compositions and the pattern of
monomer incorporation over time. This was investigated by following individual monomer
consumption rates by 1H-NMR spectroscopy. Fluorescence studies revealed that the
fluorescence behaviour of A2 and B2 was maintained during the copolymerisation.
Latex particles, with fluorescent behaviour, were synthesized via in situ miniemulsion
polymerisation. High molecular weight copolymers with monodisperse particle sizes (nm
range) were obtained. A bench-top UV lamp and UV-reflectance studies confirmed the fact that fluorescent latex
particles can be identified and quantified respectively, when dispersed in paints that are
either free of titanium dioxide or paints that contain titanium dioxide. / AFRIKAANSE OPSOMMING: Die diversiteit van chemiese en molekulêre merkers in ‘n verskeidenheid van toepassings is
al telkemale geïllustreer. Een van die mees belangrike toepassings in die industrie is die
gebruik van chemiese merkers vir produkregistrasie. Industrieë wat goeie produkte verskaf
moet die egtheid van hul produkte kan verseker deur duplikasie via nadruk (Eng: piracy)
deur ander te voorkom. Fluoresserende merkers is chemiese stowwe wat aan die meeste
van die tegniese en kommersiële vereistes voldoen om as uitstekende merkers te dien. Die
sintese van die merkers is gewoonlik nie tydrowend nie, beïnvloed nie die integriteit van
die produk nie, het min of geen impak op die gebruike van die produk of die omgewing en
kan deur relatief eenvoudige prosedures bepaal word. Die doel van hierdie studie was die
sintese van fluoresserendepolimere om as merkers in die verfindustrie te dien.
7-Hidroksie-2H-chromen-2-oon (A1) en 7-hidroksie-4-metiel-2H-chromen-2-oon (B1),
fluoresserende hidroksielverbindings wat kommersieël beskikbaar is, is gekies as
uitgangstowwe vir die bereiding van die merkers in hierdie studie. ‘n Esterifikasie-reaksie
het gelei tot die produksie van 2-okso-2H-chromen-7-ielakrilaat (A2) en 4-metiel-2-okso-
2H-chromen-7-ielakrilaat (B2). Hierdie produkte is tipiese akrilaat-tipe monomere wat
benodig word vir polimerisasie. Ondersoeke het getoon dat fluoressensie behoue tydens
esterifikasie gebly het.
Die kopolimere poli(MMA-ko-A2), poli(MMA-ko-B2), poli(BA-ko-A2) en poli(BA-ko-B2)
is deur homogene vry-radikaal-geïnisieerde kopolimerisasie gesintetiseer. Daar is vasgestel
hoe die kopolimeersamestelling geaffekteer is deur die samestelling van die reagense (Eng:
feed composition) en die patroon van monomeer inkorporasie met tyd. Dit was ondersoek
deur die tempo van verbruik van die individuele monomere d.m.v. 1H-KMR spektroskopie
te bepaal. Daar is verder vasgestel dat die fluoressensie van A2 en B2 gedurende
kopolimerisasie behoue gebly het. Latekspartikels, met fluoressensie gedrag, is via in-situ
mini-emulsie-polimerisasie gesintetiseer. Hoë molekulêre massa kopolimere met
monodisperse partikelgroottes (in die order van nanometers) is verkry. Deur van ‘n UV-lamp en UV-refleksie studies gebruik te maak is daar bepaal dat
fluoresserende latekspartikels in polimere, in verf - wat of titaniumdioksied bevat of geen
titaniumdioksied bevat nie -, beide geïdentifiseer and gekwantifiseer kan word.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:sun/oai:scholar.sun.ac.za:10019.1/16414 |
| Date | 12 1900 |
| Creators | Ramiah, Vernon |
| Contributors | Sanderson, Ronald D., University of Stellenbosch. Faculty of Science. Dept. of Chemistry and Polymer Science. |
| Publisher | Stellenbosch : University of Stellenbosch |
| Source Sets | South African National ETD Portal |
| Language | en_ZA |
| Detected Language | English |
| Type | Thesis |
| Format | xiv, 105 leaves : ill. |
| Rights | University of Stellenbosch |
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