Structure/permeability relationships of polyamide‐imides

Abstract

Abstract Structure/permeability correlations for a family of aromatic polyamide‐imides are presented. The variations in chemical structure lead to significant changes in permeability. The crystallization of PAP results in a very low permeability. The introduction of bulky group tends to increase permeability without a corresponding decrease in permselectivity. This result contributes to the inhibition of chain packing and segmental mobility. Wide‐angle X‐ray diffraction measurements of average segmental spacing of the materials and fractional free volume calculations characterize the packing of the different polymers. © 1994 John Wiley & Sons, Inc.