Emulsion Polymerization is one of the most important methods for polymerization. It is a type of radical polymerization that usually starts with an emulsion incorporating water, monomer, and surfactant. The most common type of emulsion polymerization is an oil-in-water emulsion, in which droplets of monomer (the oil) are emulsified (with surfactants) in a continuous phase of water. Water-soluble polymers, such as certain polyvinyl alcohols or hydroxyethyl celluloses, can also be used to act as emulsifiers/stabilizers. The name “emulsion polymerization” is a misnomer that arises from a historical misconception. Rather than occurring in emulsion droplets, polymerization takes place in the latex/colloid particles that form spontaneously in the first few minutes of the process. These latex particles are typically 100 nm in size and are made of many individual polymer chains.
- The technique is used for the production of a large number of commercial plastics & elastomers.
- The system consists of water-insoluble monomer, dispersion medium & surface-active agents ( soaps and detergents ) and a water-soluble initiator ( potassium per sulphat/ H2O2, etc )
- The monomer is dispersed in the aqueous phase, hot as discrete droplets, but as a uniform emulsion.
- The size of the monomer droplet is around 0.5 to 10 v.
- This method is widely used for the production of polyvinyl chloride, polyethylene, polystyrene.
- Heat control is easy. Easy agitation.
- The rate of polymerization is high.
- A very high molecular weight polymer is obtained.
- The final product can be used as-is and does not generally need to be altered or processed.
- The product contains high impurity.