A novel curing agent, poly (amide-amidic acid) (PAA), was used to cure tetraglycidyl 4,4'-diaminodiphenylmethane (TGDDM). The initial cure and exothermic peak temperatures increased with increase in PAA content. The mechanism for the cure of TGDDM/PAA was proposed which involved, besides TGDDM cure, PAA imidization in the system. Examination of the morphology of the fractured surface using scanning electron microscopy showed that curing with PAA improved more the fracture toughness as compared to the conventional 4,4'-diaminodiphenylsulfone (DDS), and rendered TGDDM more fire resistant with higher char yield. (C) 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012