Modeling of Two-Step Supercritical CO2 Foaming to Fabricate Poly(ε-caprolactone) Scaffolds

A mathematical model was developed based on the Amon and Denson model for supercritical foaming (SCF) with a two-step depressurization rate. The model was provided according to the law of conservation of momentum, the law of conservation of mass, and a reformulation of the shell size for the second step of depressurization in comparison with the shell size for the first step of depressurization. The model was validated using the experimental data of SCF from polycaprolactone plus CO2 at 300 bar, 50 degrees C, a solubilization time of 2 h, a first depressurization rate of 28.6 bar min(-1), and a second depressurization rate of 200 bar min(-1). The comparison showed a significant improvement of the model accuracy for predicting the average pore radius of the scaffold compared to the original Amon and Denson model.