Acrylonitrile-butadiene-styrene (ABS)/functionalized-graphene nanocomposites were synthesized using the solution-blending method in chloroform. A dispersion of graphite oxide was added to a solution of the ammonium salt of octadecylamine (C18) to form octadecylamine-graphene (C18-graphene), which was then used as a functionalized graphene in the preparation of ABS nanocomposite films. ABS nanocomposite films with different C18-graphene contents (03 wt %) were compared in terms of their thermomechanical properties and morphology. Despite the relatively low C18-graphene loadings studied, the nanocomposite films exhibited greatly improved thermomechanical properties compared with pure ABS. (c) 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011