Thesis (MSc (Chemistry and Polymer Science))--University of Stellenbosch, 2005. / Synthesis of two surfmers (cationic and anionic) was carried out and the surfmers were used
to stabilize particles in miniemulsion polymerization. Surfmers were used to eliminate
adverse effects associated with free surfactant in the final product e.g. films and coatings. The
Reversible Addition Fragmentation chain Transfer (RAFT) polymerization process was used
in miniemulsion polymerization reactions to control the molecular weight distribution. RAFT
offers a number of advantages that include its compatibility with a wide range of monomers
and solvents. Moreover block copolymer synthesis is possible via chain extension.
A comparative study between classical surfactants and surfmers was conducted in regard to
reaction rates and molar mass distribution. The rates of reactions of surfmer stabilized RAFT
miniemulsion polymerization of Styrene and MMA were similar (in most cases) to classical
surfactant stabilized RAFT miniemulsion polymerization reactions. The final particle sizes
were also similar for polystyrene latexes stabilized by surfmers and classical surfactants.
However PMMA latexes stabilized by surfmers had larger particle sizes compared to latexes
stabilized by classical surfactants.
The surfmers were also oligomerized in homogeneous media using the RAFT process and
their Mn values were estimated using UV-VIS spectroscopy. The oligosurfmers were then
used as emulsifiers in RAFT miniemulsion polymerization. The rates of reaction were slower
than rates obtain when the surfmers (monomer or oligosurfmers) were used directly as
emulsifiers in RAFT miniemulsion polymerization of styrene and MMA. The final latex
particle sizes obtained with oligosurfmers were also larger than that of latex stabilized by their
parent monomers.
The RAFT process was successfully applied in miniemulsion polymerization in both classical
surfactant and surfmer stabilized miniemulsions. The molecular weight increased with
conversion showing that the molecular weights of the polymers were controlled.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:sun/oai:scholar.sun.ac.za:10019.1/2946 |
| Date | 12 1900 |
| Creators | Matahwa, Howard |
| Contributors | Sanderson, R. 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 | English |
| Detected Language | English |
| Type | Thesis |
| Rights | University of Stellenbosch |
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