Mathematical method for polymerised styrene butadiene rubber 1502 pyrolysis residue and gasoline differentiation

During fire investigation, gasoline, as a common accelerant, is produced by petroleum cracking. However, the pyrolysis residues of other petrochemicals may interfere with gasoline identification. Polymerised styrene butadiene rubber (SBR) 1502 has combustion characteristics highly consistent with those of gasoline, thus having a great effect on gasoline identification. This study investigated the pyrolysis process of SBR 1502 by using thermogravimetric–differential scanning calorimetry (TG–DSC) and gas chromatography–mass spectrometry (GC–MS) to examine the residues during combustion stages, including pyrolysis and nonpyrolysis stages. The results indicated that 2,3-dimethylnaphthalene in the pyrolysis residues of SBR 1502 in pyrolysis stages 2 and 3 was lacked. However, when SBR 1502 only undergoes the first pyrolysis stage or even earlier (Nonpyrolysis stage), the characteristic components in the residue are similar to gasoline. In addition, mathematical methods were applied to analyse relevance and differences between SBR 1502 and gasoline. The conclusion was that the Pearson product-moment correlation was > 0.990, which may interfere with the identification, and principal component analysis could efficiently distinguish them. The current results can provide an accurate and feasible basis for fire investigation.