Plasticised chlorinated poly(vinyl chloride)-PY/GC/MS studies pertinent to the role of FeOOH as a smoke suppressant

This paper describes experiments and results that have been obtained from a pyrolysis/gas chromatography/mass spectroscopy study on chlorinated polyvinyl chloride (CPVC-65% Cl) containing two commercially available plasticisers, namely, DOP and Santicizer 2148 with and without modest amounts of an iron (III) smoke suppressing compound. Careful analysis of the mass spectra obtained from the pyrolysis products has shown that the smoke suppressing effect of basic iron (III) oxide (FeOOH) is essentially the result of two sets of chemical reactions. This iron compound reacts with the CPVC polymer and the plasticisers present. Increased amounts of char formed from the CPVC combined with changes in the path of decomposition during pyrolysis of both plasticisers to give fewer smoke precursor molecules resulted in a significant reduction in smoke formation.