What is Emulsion Polymerization?

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.

Emulsion

  • 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.

Advantages

  1. Heat control is easy. Easy agitation.
  2. The rate of polymerization is high.
  3. A very high molecular weight polymer is obtained.
  4. The final product can be used as-is and does not generally need to be altered or processed.

Disadvantages

  1. Costly
  2. The product contains high impurity.

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