Abstract: Pyrolysis models represent the fundamental mechanism of fire spread modelling, and are also important tools for assessing the flammability properties of materials. Within these models the reaction rates of materials can be characterized by a set of parameters such as the preexponential factor (A), the energy of activation (E) and the reaction mechanism f(a). To obtain automatically a reaction scheme we use in this paper the change in mass loss rate during pyrolysis. This is possible by hypothesizing that the polymer mass loss rate is a chain of stable successive processes characterized by a constant mass loss rate. Once the reaction scheme is fixed, we suppose Arrhenius-like behaviour obtaining the kinetic triplet for each reaction step; the apparent activation energy, the pre-exponential factor and the global reaction mechanism. The interpretation was applied to thermo-oxidation and decomposition of lineal low-density polyethylene performed by simultaneous thermal analysis.

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