Methods for of synthesizing a polymer functionalized nanoparticle are provided. The method can comprise: attaching an anchoring compound to a nanoparticle; attaching a RAFT agent to the anchoring compound; and polymerizing a plurality of butadiene-derived monomers on the anchoring compound to form a polymeric chain covalently bonded to the nanoparticle via the anchoring compound. Polymer functionalized nanoparticles are also provided that include a nanoparticle defining a surface; a butadiene-derived polymeric chain covalently bonded to the surface of the nanoparticle. Nanocomposites are also provided that include a plurality of such polymer functionalized nanoparticles dispersed within a polymeric matrix.