An investigation of emulsion polymerisation of butyl acrylate in batch and semibatch
reactors has been carried out. The important phenomena of particle formation and
kinetics in semibatch emulsion reactors with neat monomer feed and monomer
emulsion feed have been studied. An investigation of batch emulsion polymerisation
of butyl acrylate was also undertaken in order to provide the supporting evidence to
elucidate particle formation in the semibatch emulsion process.
Different start-up procedures were studied to determine their effect on the particle
formation and kinetics of the polymerisation reaction. The effects of monomer
distribution, emulsifier distribution, initiator distribution, feed rate, temperature and
pre-period time on the particle formation and steady-state rate of polymerisation were
investigated. Experimental studies reveal that particle formation in semibatch
emulsion polymerisation is influenced by partitioning of ingredients, such as
emulsifier and monomer, between the charge and the feed rate and controlling the
growth rate of particles at monomer-starved conditions. The latter is applied by
adjusting the monomer or monomer emulsion feed rate at a desired level.
Changes in start-up procedure were found to have a significant effect not only on the
transients before a steady-state, but also on the ultimate steady-state rate of
polymerisation reaction achieved and final number of particles obtained. All variables
affecting primary and secondary particle formation, and especially emulsifier
concentration, could equally influence the steady-state rate of polymerisation reaction.
Evidence was obtained indicating that secondary nucleation can occur through
homogenous nucleation. The particle size distribution (PSD) development in the
course of reaction for the semibatch emulsion process was investigated. Partitioning
of ingredients between the charge and the feed and monomer starved nucleation were
founa to be the main two factors that control the PSD and number of particles formed.
A Doctoral Thesis. Submitted in partial fulfilment of the requirements for the award of Doctor of Philosophy of Loughborough University.