ABSTRACT
The suspension and emulsion polymerization of polyvinyl chloride (PVC) from vinyl chloride monomer (VCM) accounts for about 90% of the total production of PVC. PVC is insoluble in VCM, precipitates as very fine particles, and is swollen by large amounts of VCM. VCM is present during the polymerization, in particular inside the PVC particles, but also in the water phase of the slurry and in the gas phase inside the reactor. The PVC slurry is transferred to a closed slurry blend tank and from there to the stripper. Dehydro-chlorination of the PVC is known to occur at temperatures around 100°C, and a certain reduction of the whiteness is usually noted. Influence on heat stability is negligible at worst. Devolatilization of PVC also includes removal of the large amounts of water and of the still remaining traces of residual VCM.
