The study of seeded emulsion polymerization of vinyl acetate in the absence of emulsifiers,
with potassium persulfate as an initiator has been conducted in order to investigate
the kinetics and mechanism of particle nucleation. Poly(vinyl acetate) latex particles are
stabilized by the ionic end groups from decomposition of initiator. The polymerization
behaviour of vinyl acetate in the water phase has been clarified.
The variation of the polymerization rate with changes in initiator concentration,
monomer-polymer ratio, and stirring speed were determined. The polymerization rate of
seeded emulsion polymerization of vinyl acetate is dependent on the initiator concentration
to the 0.60 ± 0.05 power, however, it is independent of the monomer-polymer ratio. There
was no significant change in polymerization rate when the stirring rate was changed from
50 to 150 rpm, but, the polymerization rate was considerably reduced when the stirring rate
was increased to 300 rpm.
New small particles were formed in the system where the monomer-polymer ratio was
substantial large (that is the system containing a small amount of seed particles).
The emulsifier-free emulsion polymerization of vinyl acetate in the absence of seed
particles was also investigated. It was found that the polymerization rate is proportional to
the 0.69 power of initial monomer concentration.
A Master's Thesis. Submitted in partial fulfilment of the requirements for the award of Master of Philosophy of Loughborough University.