Description of tire pyrolysis by thermal degradation behaviour of main components

In the first part of this work, several straight rubbers (natural rubber, three styrene-butadiene rubbers with different styrene and oil contents and butadiene rubber) are characterized by thermogravimetric/mass spectrometric (TG/MS) analysis. Additionally, the influence of three typical tire additives ZnO, sulfur and carbon black on the thermal degradation of the straight rubbers is analyzed by TG/MS experiments. In the second part, rubber mixtures and tire parts are investigated by TG/MS and gaschromatographic/mass spectrometric (GC/MS) measurements. It turned out that the GUMS spectra of the volatile pyrolysis products of rubber mixtures can be composed from the spectra of their rubber components. The multi-step DTG curves of the rubber mixtures can be separated in sections according to the thermal decomposition of their straight elastomers. DTG curves of tire parts are superposed from the DTG curves of their main rubber components, with sufficient approximation of the experimental DTG curves. Furthermore, from TG experiments formal kinetic parameters are derived for the investigated straight rubbers. The thermal decomposition of tire parts can then also be calculated with the formal kinetic parameters for the thermal decomposition of their rubber components. (c) 2005 Elsevier B.V. All rights reserved.