Synthesis of aromatic polyamides from reactive N, N′‐isophthaloyldi(thiolactam)s and aromatic diamines under mild conditions

Solution condensation polymerization of new reactive diamides, N, N′‐isophthaloyldipyrrolidine‐2‐thione (1a) and N, N′‐isophthaloyldiperhydroazepine‐2‐thione (1b), with aromatic diamines 2 in 1‐methyl‐2‐pyrrolidone at room temperature or above leads to polyamides 3 with moderate molecular weights. The ease of aminolysis of these diamides is discussed in relation to the good leaving nature of the thiolactam moieties and an intramolecular general base catalysis. The condensation polymerization is strongly catalyzed by 1‐hydroxybenzotriazole giving aromatic polyamides with higher inherent viscosities up to 0,9 dl.g−1.