The production of rubber‐modified polystyrene. I. Rheological behavior of the polymerizing system

The rheological behavior of the two‐phase systems consisting of a polystyrene‐in‐styrene phase distributed in a rubber‐in‐styrene phase is shown to exhibit increasing non‐Newtonian behavior up to the phase inversion point, as a consequence of its two phase nature. The equation is recommended for the prediction of the viscosity of the polymerizing mass up to phase inversion during the production of HIPS by the in situ bulk polymerization of styrene in the presence of dissolved rubber.