Citation

Hirschler MM. Fire Mater. 2005; 29(6): 367-382.

Copyright

(Copyright © 2005, John Wiley and Sons)

DOI

unavailable

PMID

unavailable

Abstract

The dehydrochlorination and the thermal decomposition of five PVC materials was studied using two techniques: a batch analytical method, combining ion chromatography and atomic absorption and continuous thermogravimetry. The temperatures studied ranged from 60 degrees C to 120 degrees C, over a period of almost one year (50 weeks). It was found that a very large proportion of the soluble chloride emitted early on by the PVC materials into the liquid phase is not hydrogen chloride. None of the five materials tested emitted significant amounts of HCl at temperatures lower than 105 degrees C. The emissions at 90 degrees C after 50 weeks ranged from less than 0.01 Phi g/g to 23.62 Phi g/g. Furthermore, one of the materials tested emitted virtually no HCI, even at 105 degrees C, as the amount of F[Cl measured was almost indistinguishable from the normal background of the analytical instruments (37.30 Phi g/g after 50 weeks). Numerical calculations of kinetic reaction rates and extrapolation of the results to use temperatures (40 degrees C) indicate that property stabilized PVC compounds will be unlikely to lose 1% of the mass of PVC as HCl until 2 billion years have passed. This number has no physical meaning as such and may be incorrect by a vast margin, but it clearly indicates that a 1% loss of HCl is unlikely to occur during the useful lifetime of a commercial product into which the PVC material has been fabricated. This is a conservative estimate, which ignores the much higher activation energy for dehydrochlorination at temperatures below the glass transition temperature (ca. 85 degrees C).