Biodegradable crystalline poly(butylene succinate) (PBSU) are miscible with amorphous poly(vinyl phenol) (PVPh). Neat PBSU and PBSU blended with PVPh show complex melting behavior after nonisothermal melt crystallization at constant cooling rates. Both neat and blended PBSU can show one, two, or three melting peaks depending on the blend composition, cooling rate, and heating rate. A model was proposed to explain the origin of the complex melting behavior of PBSU through conventional differential scanning calorimetry (DSC) and temperature-modulated differential scanning calorimetry (TMDSC) studies. (c) 2007 Wiley Periodicals, Inc.