A poly[(butylene succinate)-co-adipate] (PBSA) nanocomposite containing 3 wt% organically modified montmorillonite exhibited an improvement in tenacity (elongation at break) as compared to the neat PBSA. The nanocomposite also showed moderate improvement in tensile modulus and strength. The small-angle X-ray scattering and transmission electron microscopy were used to investigate the exact tenacity improvement mechanism in the nanocomposite. (C) 2010 Elsevier Ltd. All rights reserved.