Emulsionspolymerisation

Emulsion polymerisation, or emulsion polymerization, is a type of radical polymerization conducted in water in which monomer is dispersed as droplets or micelles stabilized by surfactants. The aqueous phase contains a surface-active agent that stabilizes the dispersed droplets or micelles, and polymerization proceeds within these dispersed domains to form polymer particles, typically yielding a latex. Initiation is usually from water-soluble initiators (for example persulfates) that generate radicals in the continuous phase and enter the droplets or micelles to start chain growth. The polymerization is carried out under controlled temperature and agitation, and particle growth is governed by micellar or droplet dynamics, coagulation control, and stabilizer efficiency.

Common monomers include styrene, butadiene, vinyl acetate, and various acrylates and methacrylates; copolymerization allows the synthesis of a wide range of materials for paints, coatings, adhesives, and paper or textile finishes. The method provides high conversion, rapid kinetics, and the possibility to obtain high solids dispersions with relatively low viscosity.

Advantages include effective heat management in water, ease of scale-up, and the ability to produce latexes with narrow particle size distributions. Disadvantages include residual surfactant and stabilizer in the final polymer, sensitivities to impurities, and the need for purification in some applications.

Emulsion polymerisation is widely used to manufacture latex paints, coatings, adhesives, and synthetic rubbers. See also radical polymerization, suspension polymerization, and latex technology.