PVC resin is a white powder commonly used to produce thermoplastics. Other members of the vinyl family can be used for similar applications, but PVC tends to be the most popular member of that family.
About 80% of production involves suspension polymerization. Emulsion polymerization accounts for about 12%, and bulk polymerizationaccounts for 8%. Suspension polymerization affords particles with average diameters of 100â€“180 Î¼m, whereas emulsion polymerization gives much smaller particles of average size around 0.2 Î¼m. VCM and water are introduced into the reactor along with a polymerization initiator and other additives. The contents of the reaction vessel are pressurized and continually mixed to maintain the suspension and ensure a uniform particle size of the PVC resin. The reaction is exothermic and thus requires cooling. As the volume is reduced during the reaction (PVC is denser than VCM), water is continually added to the mixture to maintain the suspension.