An improved method is provided to prepare reinforced resin nanocomposites without the need of surfactants or coupling agents. The present invention comprises the use of monomers for improving the dispersion of nano-sized materials and enhancing the particle/matrix interaction. One comprises mixing a plurality of nanoparticles with a monomer resin to form a mixture, blending a catalyst and a promoter with the mixture, and curing the blended mixture to form a polymerized nanocomposite. The monomers, which serve to stabilize the nanoparticles, are covalently bound onto the nanoparticle surface and copolymerize with non-bound monomers after introduction of a catalyst and a promoter that initiate polymerization. Without any additional surfactant or coupling agent, the resin is chemically bound onto the nanoparticle surface and protects the iron nanoparticles from agglomeration and oxidation.