New aromatic co-polyamide-imides (coPAIs) containing both carboxyl and hydroxyl groups
in the repeating units were synthesized for the first time. Transport, thermal and
morphological properties of dense nonporous membranes from PAIs obtained using the
diacid chloride of 2-(4-carboxyphenyl)-1,3-dioxoisoindoline-5-carboxylic acid and
diamines 5,5′-methylene-bis (2-aminophenol)) and 3,5-Diaminobenzoic acid, taken in
molar ratios of 7:3, 1:1, and 3:7, have been studied. High levels of membrane permeability
accompanied by high selectivity for mixtures of liquids with significantly different
polarities were determined by realization of intra- and intermolecular interactions
in polymer, which was proved by thermal analyses and hydrodynamic characteristics
of coPAIs. This effect is discussed in the context of the effectiveness of intermolecular
interactions between polymer chains containing carboxyl and hydroxyl functional groups.
