Abstract: A process has now been discovered that permits the simultaneous crosslinking and derivation of an, optionally hydrogenated, polymer whose backbone is composed of a conjugated diene, an unsaturated nitrile and an unsaturated carboxylic acid in the presence of a coupling/condensing agent. This permits the preparation of a novel polymeric material that is an optionally hydrogenated polymer of a conjugated diene, an unsaturated nitrile and a derived unsaturated acid. It has also been found that this novel polymeric material has unexpected and valuable properties.