SOLUBILITIES AND DIFFUSIVITIES OF PERMANENT GASES IN POLY(PHENOLPHTHALEIN TEREPHTHALATE)

Solubility and diffusivity of pure carbon dioxide, methane, ethane, oxygen, argon, and nitrogen in solution-polymerized poly(phenolphthalein terephthalate) [PPha-tere] were determined from independent sorption and permeation measurements. PPha-tere absorbs ~8 wt % carbon dioxide at 35 °C (20 atm), roughly 80% more than polycarbonate or polysulfone does. The carbon dioxide permeability of PPha at 35 °C exceeds 20 Barrers. The permselectivities, defined as the ratio of pure-gas permeabilities, for CO2/CH4 and CO2/C2H6, respectively, are greater than 28 and 59 at 35 °C. The dual-mode model formalism was adopted to analyze the sorption and permeation data. Inference regarding the physical state of absorbed gas molecules is made. The equilibrium sorption parameters and the diffusion coefficients are correlated with the critical temperature of the gas and the dimension of the gas, respectively. © 1990, American Chemical Society. All rights reserved.