Modeling flow and cell formation in foam sheet extrusion of polystyrene with <scp>CO₂</scp> and co‐blowing agents. Part I: Material model

Abstract In foam extrusion, process parameters, material properties, and the blowing agent have an influence on resulting properties. For safety environmental reasons, carbon dioxide (CO 2 ) has gained importance as a physical for production of low‐density polystyrene sheets. The sole use CO often leads to corrugation, open cell structures, or surface defects sheet. As alternative, mixtures based organic solvents such ethanol, acetone, ethyl acetate can be used, changing solubility flow behavior gas‐loaded melt. Modeling foaming in extrusion die could help reduce experimental effort accelerate development novel mixtures. A model approach describe melt loaded with various is developed. Part I article describes modeling that is, rheological by Carreau‐WLF shift factors temperature, pressure, effects glass transition temperature. Solubility modeled combined Henry coefficient approach, showing good agreement data. Based model, developed II this work.