GAS-TRANSPORT IN POLYMERS BASED ON BISPHENOL-A

Permeation measurements for CO//2, CH//4, O//2, N//2, and He weer made with three polymers based on bisphenol-A, namely a polyhydroxyether, a polyetherimide, and a polyarylate. Measurements were also made for CO//2 and CH//4 in polysulfone. The data for CO//2, CH//4, and N//2 plus previous data for these gases in polycarbonate and polysulfone were combined with equilibrium gas sorption data and analyzed with the dual mode/partial immobilization model and the more recent gas-polymer-matrix model. A comparison of the two models was done on the basis of physical interpretations of the resulting parameters. The diffusion coefficient for the Henry's law population was related to the kinetic diameter of the gas. The infinite dilution, Henry's law population was related to the kinetic diameter of the gas. The infinite dilution, Henry's law, and Langmuir diffusion coefficients were related to the free volume of the polymer. The work suggests a means of order-of-magnitude estimation of diffusion coefficients from polymer density and molecular structure.