A new iterative model-free (isoconversional) method with integration over a given range of conversion for determination of the activation energy using non-isothermal data recorded at several heating rates has been suggested The advantages of applying this method in comparison with often used linear and nonlinear isoconversional methods are put in evidence The suggested method was applied to experimental non-isothermal data for degradation of polyvinyl chloride decomposition of ammonium perchlorate and crystallization of poly(ethylene terephthalate) melt The so obtained values of the activation energy were compared with those resulting from other methods of analysis (C) 2010 Elsevier B V All rights reserved