Which polymerization method is commonly used for PVC production?

Several polymerization methods are used for PVC (polyvinyl chloride) production, but the most common methods are suspension polymerization and emulsion polymerization. Suspension polymerization involves dispersing vinyl chloride monomer as droplets in water, using a suspending agent to prevent the droplets from coalescing. The polymerization is initiated within these droplets, resulting in PVC particles with a relatively large particle size (typically 50-200 micrometers). Emulsion polymerization also involves dispersing vinyl chloride monomer in water, but it uses a surfactant to create micelles, which are small aggregates of surfactant molecules that solubilize the monomer. The polymerization is initiated within these micelles, resulting in PVC particles with a much smaller particle size (typically 0.1-3 micrometers). While both suspension and emulsion polymerization are widely used, suspension polymerization is often favored for producing PVC resins used in rigid applications, while emulsion polymerization is often used for producing PVC resins used in flexible applications. Another method, bulk polymerization, is used but less common than suspension and emulsion. It involves polymerizing the monomer in the absence of a dispersing medium.