Modeling of supercritical CO2 extraction of contaminants from post-consumer polypropylene: Solubilities and diffusion coefficients in swollen polymer at varying pressure and temperature conditions
Supercritical CO2 extraction mechanism can be simplified to a process controlled by diffusion and solubility. Diffusion coefficient and solubility depend strongly on contaminant molecular structure. Important role played by the matrix swelling by SCCO2 pressure on the diffusion coefficient enhancement. Swelling induced by CO2 pressure decreases the activation energy for diffusion of contaminants in polypropylene. Pressure has a positive effect on solubility in supercritical CO2, whereas temperature effect is complex.