Phase equilibria of CO2-PET-phenol system and generation of PET powders bysupercritical CO2 anti-solvent

Phase equilibria of CO2=Phenol-Poly(ethylene terephthalate) (PET) ternary s ystem were investigated at 318.15 and 326.15 K and at pressures ranging fro m 6 to 17 MPa. The results show that the solubility of CO2 in PET/phenol so lution increases with pressure, and decreases with temperature. The solubil ity of PET in phenol (on CO2-free basis) decreases significantly with press ure at pressures lower than 10 MPa at 318.15 K and 11 MPa at 326.15 K, but increases slightly with pressure at higher pressures. On the basis of the p hase behavior studied, PET powders were produced by the gas anti-solvent (C AS) process, and the morphology of the precipitated PET was examined using scanning electron microscopy. (C) 2000 Elsevier Science Ltd. All rights res erved.