Non-isothermal crystallization and Subsequent melting behaviour of iPP/sPP blends of various compositions were investigated by differential scanning calorimetry (DSC). Results revealed that sPP crystallizes at a slower rate than iPP. This effect is attenuated when the cooling rate is increased up to 20 degrees C/min and 25 degrees C/min. DSC scans showed that stability of primary crystallites of sPP and perfection of iPP crystallites were both increased by decreasing cooling rate. Effective activation energy (Delta E-Xt) of sPP, calculated using Friedman iso-conversional method, was found to be lower in iPP/sPP blend than in neat sPP whereas Delta F-X1 of iPP is not modified. Results were analysed through Avrami, Ozawa and Mo models. They both showed a decrease of crystal growth dimensionality for both iPP and sPP in iPP/sPP blends compared with neat iPP and sPR The kinetic parameters U and K-g were determined by the Hoffman-Lauritzen theory. (C) 2008 Elsevier BV. All rights reserved.