Styrene-butadiene rubber pyrolysis: Products, kinetics, modelling

The pyrolysis of SBR (styrene-butadiene rubber) was investigated by a dynamic thermogravimetric apparatus, where it is possible to treat samples in form of cylinders with a weight of about 30 g. Various heating rates between 0.1 and 1 degrees C/s were investigated. A distributed parameter model able to describe heating inside the sample and its kinetics of decomposition was built. The pyrolysis enthalpy seems to be a very important parameter; its best fitting value was identified equal to 200 kJ/kg. Light gases produced by pyrolysis were analyzed and the influence of heating rate and sample size on the pyrolysis products (gases, tar, and char) was studied. This investigation showed that for big samples (some tenths of grams) the influence of heating rate on the pyrolysis products is often less important than for few mg samples, as often reported in the literature. Different pyrolysis conditions lead to strong variation of light gas yield, but the molar fraction of most of the light gases is almost constant. (C) 2008 Elsevier B.V. All rights reserved.