Cell nucleation and growth (foam expansion) were initiated by the thermodynamic instability created by depressurization
Depressurization rates, dp/dt, of 4bar/s and 14bar/s were used here. Stabilization of the foam structures resulted from cooling induced by the pressure release and maintained by the cooling system of the chamber. Figure 1 summarizes the foaming parameters used for the different materials. A minimum of five foams were prepared for each set of conditions and for each material.