Theoretical analysis of the devolatilizing performance of an intermeshing co‐rotating twin‐screw extruder with a type of square‐channel flighted element

Abstract

AbstractThe local film interfaces in the long vent section of an intermeshing, co‐rotating twin‐screw extruder (ICoTSE) with square‐channel flights (SFs) and the exposure time to the vapor phase were analyzed. A theoretical overall film‐interface geometry factor (OFIGFcal) was calculated from a new devolatilization (DV) model proposed previously by the authors, and the predictions were compared to the experimental results (OFIGFexp) for polystyrene/ethylbenzene (PS/EB). The OFIGF represents a measure of the devolatilization performance of the long vent section. The ratio of the experimental to the predicted apparent film interface areas was 5.5, which demonstrates the enhancing effect of the roughness and bubble‐forming behavior of the film interfaces on DV. The predicted concentrations of EB in the PS melt at the exit of the long vent section agreed well with experimental results.