Abstract: Based polystyrene(PS)/CO2 foaming system, using cell model, three mathematical model for bubble growth were derived based on different constitutive equations: Newtonian fluid, power law fluid, and dewitt fluid. Comparing with experimental results, the effect of physical parameters such as melt elasticity and non-Newtonian nature on the bubble growth process was studied. It was showed that dewitt model was suitable for the bobble growth, the melt elasticity promoted the bobble growth in the early growth, the non-Newtonian behavior of the melt had effect in the whole bobble growth process.

Key words: carbon dioxide, simulation, polystyrene, foaming, constitutive equations, bubble growth