The invention concerns a polymer material consisting of macromolecular chains bound by hydrogen bonds, wherein: the macromolecular chains consist of a polymer skeleton whereon is fixed by at least one covalent bond a modifying agent, the modifying agent comprising, assembled in a common molecule, one or more associative groups capable of being bound by hydrogen bonds and one or more reactive groups capable of forming covalent bonds with the polymer skeleton, at least one of the associative groups of the modifying agent is an imidazolidone heterocycle, the macromolecular chains bear on average, 1 to 10 imidazolidone groups per chain. The average number of imidazolidone groups to be introduced into the macromolecular chains depends both on the average mass of said chains and the final properties desired for the material.