CO₂ Induced Foaming Behavior of Polystyrene near the Glass Transition

Figure 3

Photograph of a PS (1 mm thick × 20 mm diameter) sample 600 sec after the onset of depressurization after holding at 24 bar (CO₂ pressure) and 100°C for 2 hours, the photograph shows the location of three impinged bubbles and one free bubble that are considered here (scale of images is 6 × 6 mm).