Copolymer - metal composites are very interesting materials for engineering applications, as they offer tailored properties from the composing materials, such as flexibility, low density, conductivity, among others. Sulfonated polystyrene was synthesized by emulsion polymerization in an aqueous medium using Brij (polyoxyethylene 23 dodecyl ether) as surfactant. The composite material was obtained through the reduction of the metallic salt (BiCl3 or SnCl2) in a solution of dymethylformamide and the copolymer, and Brij as stabilizers. Scanning electron microscopy images evidenced evenly distributed particles of metal. Isolated particles were observed in the case of Tin, while Bismuth showed bunches, as reported in previous publications. Differential scanning calorimetry tests depicted the expected behavior of Tg for the sulphonated polystyrene with small variations in the composites. A peak for the melting point around 232 °C was observed for tin, while the system Polymer–Bi had no evidence of bismuth melting point, these differences could be related to bismuth crystal size.