The instant invention relates to poly(maleimide-co-alkenyl benzene) centipede polymer and a method for producing the polymer by reacting a poly(alkenyl benzene-co-maleic anhydride) in the presence of a primary amine in a substantially dry state. The invention is further directed to a process for blending the poly(maleimide-co-alkenyl benzene) centipede polymer with elastomeric polymers, in combination with, or in substitution of, conventional extender oils, to produce extended polymers having improved properties such as tensile strength, maximum elongation, tear strength, damping properties, and the like.