Using polyamide-6 as charring agent in intumescent polypropylene formulations II. Thermal degradation

The fire performance of intumescent PP/APP/PA6/EVA19 blends were previously put forward in part I of this article. In the present part, the thermal and thermo-oxidative degradations of the formulations are modelled. The comparison between the kinetic data determined in this study and data from previous studies suggests that PP degrades before the reaction between APP and PA6. However it may be supposed that in the conditions of a fire (i.e. at high heating rate) both reactions occur simultaneously. Thus the development of an efficient protective structure is possible which could explain the fire properties of interest observed in the conditions of the cone calorimeter. (C) 2002 Elsevier Science Ltd. All rights reserved.