In this work, the compatibilization of polystyrene-and-nylon 6 mixtures with the ionomer, poly(styrene-co-sodium acrylate), is investigated. The ionomer was synthesized by emulsion polymerization. Scanning electron microscopy reveals that an appreciable size reduction of the dispersed phase is achieved in the whole composition range, when small amounts of the ionomer were added. IR spectroscopy and water absorption tests disclose that a chemical reaction occurs between the carboxylic group of the ionomer and the terminal amine group of the polyamide 6, which allows the compatibilization process. (C) 2003 Wiley Periodicals, Inc.