The comparative kinetic analysis of non-isothermal degradation process of acrylonitrile-butadiene and ethylene-propylene-diene rubber compounds. Part I

Abstract

The non-isothermal degradation processes of acrylonitrile-butadiene and ethylene-propylene-ethylidenenorbornene rubber compounds were investigated with thermogravimetric analysis (TGA) and derivative thermogravimetry (DTG), using the different calculation procedures. It was found that the acrylonitrile-butadiene (NBR) and the ethylene-propylene-diene (EPDM) rubber degradations represent the complex processes, where there are conversion regions with a constant value of the apparent activation energy (E-a). It was established that the NBR and EPDM degradation under nitrogen atmosphere can be described by the one and a half order (n = 3/2) and the first order (n = 1) reaction kinetics, respectively. A linear dependence was observed between In A and E-a at every heating rate, known as the artificial compensation effect (art-CE). It was found that the calculated differential conversion curves are in good agreement with the experimental ones, for each of the observed heating rates, thus confirming the correctness of the obtained reaction models for the NBR and EPDM degradation processes. (C) 2011 Elsevier B.V. All rights reserved.