A series of polyamides and poly(amide–imide)s were prepared by the direct poly-condensation of 2,2-bis(4-aminophenoxy) benzonitrile [4-APBN] with aromatic dicarboxylic acids and bis(carboxyphthalimide)s in N-methyl-2-pyrrolidone [NMP] with triphenyl phosphite and pyridine as condensing agents. The synthesis of 4-APBN involves a nucleophilic displacement reaction in dipolar aprotic solvent with the alkali metal salt of p-aminophenol and an activated aromatic dichloro compound. Bis(carboxyphthalimide)s were prepared by condensation of 4,4′-diaminodiphenylsulfone, 3,3′-diaminodiphenylsulfone, 4,4′-diaminodiphenylether, 4,4′-diaminodiphenylmethane, 3,3′-diaminobenzophenone, and trimellitic anhydride at a 1:2 molar ratio. The inherent viscosities of the resulting polymers were found to be in the range of 0.31–0.93 dl/g and glass transition temperatures between 235 and 298 °C. All polymers were soluble in aprotic polar solvents such as dimethylsulfoxide and NMP. The results of thermogravimetry revealed that all the polymers showed no significant weight loss before 400 °C. Wide-angle X-ray diffractograms revealed that all polymers were found to be amorphous except for the polyamide derived from isophthalic acid and polyamide–imides derived from diaminodiphenylether and diaminobenzophenone based bis(carboxyphthalimide)s.
Dr. Akanksha Saxena Pandit, Rao, V. L., Prabhakaran, P. V., and Ninan, K. N., “Synthesis and characterization of polyamides and poly(amide–imide)s derived from 2,2-bis(4-aminophenoxy) benzonitrile”, European Polymer Journal, vol. 39, pp. 401 - 405, 2003.