General aspects of emulsion polymerisation

An ab initio emulsion polymerisation involves the emulsification of one or more monomers in a continuous aqueous phase and stabilisation of the droplets by a surfactant. In a seeded emulsion polymerisation, one starts instead with a preformed seed latex. Usually, a water-soluble initiator is used to start the free-radical polymerisation. The locus of polymerisation is within the submicron polymer particles (either formed during the process or added at the start), which are swollen with monomer during the polymerisation process, and dispersed in the aqueous phase. The final product is a latex comprising a colloidal dispersion of polymer particles in water. Ab initio emulsion polymerisation differs from suspension, mini- and microemulsion polymerisations in that the particles form as a separate phase during the polymerisation process. The particle size is much smaller than those formed in a suspension polymerisation. 

1980)), can be no more than 10s orders of magnitude less than the time during which the latex particle is polymerising. 

The fact that particles in an emulsion polymerisation are small, much smaller than those in a (conventional) emulsion, indicates that polymerisation does not occur in the monomer droplets. If a surfactant is used above the critical micelle concentration (CMC), in the system, then micelles form. A micelle is an aggregate of 10 surfactant molecules. 

Emulsion polymerisation kinetics have important differences from solution and bulk polymerisations. These differences can lead to many advantages for example, an increase in molar mass can be achieved without reducing the rate of polymerisation. Emulsion polymerisation is known for its relatively high rates of polymerisation and high molar masses as compared to other polymerisation techniques. A disadvantage of emulsion polymerisation is the presence of surfactant and other additives, which may result in deleterious properties under some circumstances. 

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