Intercalated and exfoliated nanocomposites of biodegradable poly(butylene adipate-co-terephthalate) (PBAT) and Cloisite 30B (C30B) were fabricated by a solution-casting method to study the effects of the clay loading on the crystallization behavior, thermal stability, and dynamic mechanical properties of PBAT in PBAT/C30B nanocomposites. X-ray diffraction and transmission electron microscopy results indicated the formation of exfoliated nanocomposites at low clay loadings (<5 wt %) and a mixture of exfoliated and intercalated nanocomposites with a clay content of 8 wt % throughout the PBAT matrix. Nonisothermal melt crystallization studies indicated that C30B enhanced the crystallization of PBAT, apparently because of a heterogeneous nucleation effect. Moreover, an attempt was made to quantitatively study the influence of the presence of C30B and its contents on the nucleation activity of PBAT in the PBAT/C30B nanocomposites. The thermal stability of PBAT decreased slightly in the nanocomposites. However, the storage modulus of PBAT apparently increased with the C30B loading increasing in the PBAT/C30B nanocomposites. (C) 2010 Wiley Periodicals, Inc. J Appl Polym Sci 119: 1426-1434, 2011