Rubber composition based on a highly saturated diene elastomer

A rubber composition based on at least:

• an elastomer matrix comprising more than 50 phr of a copolymer containing ethylene units and 1,3-diene units, the ethylene units in the copolymer representing more than 50 mol % of monomer units of the copolymer;
• a 1,3-dipolar compound corresponding to formula (I)
• Q-Sp-B (I),
• in which Q comprises a dipole containing at least one nitrogen atom, Sp is an atom or a group of atoms connecting Q to B, and B comprises an imidazole ring corresponding to formula (II)
• in which three of Z, Y, R and R′, which are identical or different, each represent an atom or a group of atoms, it being possible for Z and Y to form, together with the carbon atoms to which they are attached, a ring, and the fourth of Z, Y, R or R′ denotes a direct attachment to Sp;
• a filler comprising predominantly silica;
• and
• a crosslinking system comprising at least one radical polymerization initiator and a co-crosslinking agent selected from the group consisting of (meth)acrylate compounds, maleimide compounds, allyl compounds, vinyl compounds and mixtures thereof;
• wherein the copolymer containing ethylene units and 1,3-diene units is a copolymer of ethylene and of 1,3-diene, and
• wherein a content of co-crosslinking agent is within a range extending from 1 to 20 phr.