Solubilities of Sub- and Supercritical Carbon Dioxide in Polyester Resins

In supercritical carbon dioxide (CO2) assisted polymer processes the solubility of CO2 in a polymer plays a vital role. The higher the amount of CO2 dissolved in a poly-mer the higher is the viscosity reduction of the polymer. Solubilities of CO2 in polyester resins based on propoxy-lated bisphenol (PPB) and ethoxylated bisphenol (PEB) have been measured using a magnetic suspension bal-ance at temperatures ranging from 333 to 420 K and pressures up to 30 MPa. An optical cell has been used to independently determine the swelling of the polymers, which has been incorporated in the buoyancy correc-tion. In both polyester resins, the solubility of CO2 in-creases with increasing pressure and decreasing tem-perature as a result of variations in CO2 density. The experimental solubility has been correlated to the Sanchez–Lacombe equation of state. POLYM. ENG. SCI.