ABSTRACT
Interest in wiped-film devolatilization (WFD) of polystyrene (PS) at Monsanto became intense in the 1950’s with a focus on the removal of residual styrene (ST) from PS made in batch polymerization processes. Experimentation leading to a commercial ST/PS WFD happened in three distinct steps. First, a laboratory WFD was used to prove the feasibility of primary WFD using EB/PS. Second, a new laboratory WFD setup confirmed more efficient co-current devices and demonstrated the intended process. Finally, a pilot plant-scale operation. Visual observations with model fluids and geometry similar to WFD AA led Latinen to conclude that minimizing holdup and maximizing centrifugal effects was the best way to avoid surging in the WFD. High energy input and gross monomer removal have been achieved at pressures needed for convenient condensation in a primary WFD using a rotor with four rows of 45° tabs.
