The structure and mechanical properties of biodegradable poly(butylene succinate) (PBS)/graphene oxide (GO) composites were investigated. Chemically exfoliated GO nanosheets with an average lateral dimension of 1.50 (+/- 0.15) mu m and an average thickness of 1.18 (+/- 0.09) nm were prepared by a modified Hummers method and used for reinforcement of PBS because of its abundant oxygen-containing functional groups. The GO was dispersed as several layers in the PBS matrix through solution-blending and compression-molding methods that were characterized by transmission electron microscopy. The tensile strength, Young's modulus, and fracture energy of PBS were increased by 53, 70, and 100%, respectively, with an incorporation of 2.0 wt % of GO. The stiffness of PBS/GO composites was predicted using the HalpinTsai model and considering a two-dimensional random dispersion of GO nanoplatelets in the PBS matrix and the effective volume fraction of the reinforcement. The crystallization temperature and crystallinity of PBS were increased by the addition of GO, indicating that it acts as a nucleating agent to facilitate the crystallization of PBS. The improvement of physical and mechanical properties of biodegradable PBS with the incorporation of low loadings of GO nanoplatelets further expands its industrial uses. (c) 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013