Terpolymers having 1,4-diketo functionalities and a carbonyl group concentration of about 5-20% of polymer weight can be conveniently cured by heating with an aromatic primary diamine or its precursor and a catalytic amount of an acid having a pKa of at most about 3. Cured polymers have good physical properties and are suitable in such applications as, for example hose, tubing, wire coatings, gaskets, and seals.