Gas permeation characteristics in polyarylate/poly(butylene terephthalate) blend membranes

Abstract

The permeation properties of oxygen and nitrogen in polyarylate (PAR)/poly(butylene terephthalate) (PET) blend membranes were investigated and analyzed by using a modified two-phase model. PAR and PET are amorphous and semi-crystalline polymers, respectively, and the amorphous phases of these polymers form a miscible blend. When blended, these two polymers show a volume contraction. The effect of crystallinity on gas permeation and separation properties was also examined. The crystallinity was controlled by annealing and/or by varying its PET content. The resulting gas permeation characteristics were analyzed by using the modified two-phase model, derived from the semi-logarithmic additive rule. The experimental permeability in the amorphous phase of the blend showed a marginally negative deviation from the model. The deviation may be attributable to the volume change during blending.