A composition is disclosed comprising a styrenic first polymer, nanoclay, and an emulsifier compound, which can be blended with an additional polymer. A nanocomposite exhibits improved heat resistant properties and stiffness. In one embodiment, the additional polymer is poly(phenylene ether). An article and a method for the preparation a nanocomposite are also disclosed. In one embodiment, the process of obtaining a nanocomposite comprises emulsion polymerizing styrenic monomers in the presence of an aqueous dispersion of nanoclay and emulsifier compound, wherein an aqueous mixed dispersion comprising styrenic polymer and nanoclay is formed; coagulating the aqueous mixed dispersion with a coagulating agent to form a coagulated mixed dispersion comprising nanoclay and styrenic polymer; solidifying the coagulated mixed dispersion to form a polymeric clay concentrate comprising the nanoclay and the styrenic polymer as a carrier resin; and mixing the polymeric nanoclay concentrate, directly or indirectly with an additional polymer to form a nanocomposite.