A nanoparticle includes a copolymer comprising a vinyl-aromatic monomer and a heterocyclic monomer. The copolymer is crosslinked with a multifunctional crosslinking agent polymerizable through an addition reaction. A nanoparticle and elastomer composition is disclosed. Several methods of mixing heterocyclic and non-heterocyclic monomer nanoparticles into an elastomer are also disclosed. These methods include mixing in a multi-elements static mixer and an intermeshing mixer with venting, among others.