Expanded graphite (EG) was prepared by the exfoliation of expandable graphite under microwave irradiation. Aromatic polydisulfide/EG nanocomposites were then fabricated by absorbing cyclic (arylene disulfide) oligomers into the pores of EG. Subsequently, the nanocomposite precursor was hot-molded at 200 degrees C to carry out simultaneously the in situ ring-opening polymerization of these oligomers via free radical mechanism. The resulting aromatic polydisulfide/EG nanocomposite exhibited a intercalated nanostructure as evidenced by transmission electron microscopy (TEM) observation. Short carbon fiber (SCF) was used to further reinforce aromatic polydisulfide/EG nanocomposites. Consequently, the ternary polydisulfide/EG/SCF nanocomposites showed superior mechanical properties and good electrical conductivity. The ternary nanocomposites can be used as electrically conductive materials to prepare the bipolar plates of polymer electrolyte membrane fuel cell. (c) 2005 Elsevier B.V. All rights reserved.