A new class of macromolecular monomers (hereinafter called "macromonomers") comprises the polymerized product of at least one of an ethenylarene and a conjugated diene monomer, the product having a terminal omega-alkenyl group of at least four carbon atoms. The novel macromonomer can be copolymerized with ethylene and alpha-olefin monomers to form graft copolymers having pendant side-chains. The graft copolymers are useful as coating and molding compositions. The macromonomers can be useful as coatings on chromatographic supports for analytical and preparative separation of chemical mixtures.