The kinetic of non-isothermal crystallization of Poly (ethylene terephthalate-co-sodium-5-sulfo-iso-phthalate) (PETI) was investigated using differential scanning calorimetry (DSC). Various macrokinetic models namely the Avrami, Tobin, Ozawa, and Ziabicki were used to describe the non-isothermal crystallization process of PETI. Both of the Avrami crystallization rate constant and the Tobin crystallization rate constant were observed to increase with increasing cooling rate. The Avrami model is better than the Tobin model to describe the non-isothermal crystallization process of PETI. The Ozawa crystallization rate K-0 was found to decrease with increasing cooling rate, while Ziabicki's kinetic crystallizability parameter G(z) was found to increase with increasing cooling rate. The effective energy barrier Delta E for non-isothermal crystallization process of PETI, analyzed based on the differential iso-conversional method of Friedman, was found to be an increasing function of the relative crystallinity. (C) 2016 Elsevier B.V. All rights reserved.