Studies of the Chemical Mechanism of Smoke Particulates Formation During the Combustion of Chlorinated Polymers

Abstract

Results of qualitative and quantitative chemical analyses of stable combustion products found in smoke particulates of chlorinated pofymers are described. Chemical composition profiles have been established in both nonflaming and flaming modes, comparing pofyvinylchloride (PVC) samples with nonchlorinated polypropylene (PP). The nonflaming combustion analysis indicates similarity between the PVC and PP samples, suggesting similar degradation processes. In the flaming combustion of these polymers mainly aromatic compounds were identified, supporting a stepwise ring growth mechanism leading to the formation of the multi-ring structure of soot nuclei. The main influence of the chlorine atom appears in the higher production of the substituted polycycloaromatic hydrocarbons (PAH), which in turn may account for the observation that a higher quantity of soot is released during the combustion of PVC than during the combustion of non-chlorinated polymers. Finally, the presence of additives upon PVC soot formation seems to affect the physical rather than the chemical processes that influence smoke particulate formation.