Modelling of the High‐Impact Polystyrene Morphogenesis

Summary: High‐impact polystyrene (HIPS) is a hetero‐phase polymer with the so‐called salami morphology. Salami morphology is formed by a continuous PS phase containing micron‐sized PB domains. PB domains contain submicron‐sized irregular PS occlusions. In our modeling work we addressed several weak points of Cahn‐Hilliard model of HIPS salami morphology evolution. The weakest point of Cahn‐Hilliard model is the inherently present Ostwald ripening destabilizing or competing with graft‐stabilized domains. Two mechanism of formation of HIPS morphology are supported by the model: (i) encapsulation of graft‐stabilized PS‐rich domains in PB particles, and (ii) polymerization of styrene dissolved in PB‐rich phase and subsequent phase separation leading to PS occlusions in PB domains.