THE SOLUBILITY PARAMETERS OF AROMATIC POLYAMIDES

The degrees of swelling of rigid aromatic polyamide networks in various solvents, nonsolvents, and solvent mixtures were used to determine their solubility parameters. This was made possible because of the amorphous nature of the rigid networks and the low levels of intersegmental H-bonding. The solubility parameters are: delta = 23.0 (MPa) 1/2, delta(d) = 18.0 (MPa)1/2, delta(p) = 11.9 (MPa)1/2, and delta(H) = 7.9 (MPa)1/2. The determined values are believed to be good approximations of the solubility parameters of stiff linear aromatic polyamides, because of the essential identity of their structure and the stiff segments in the networks.