Thermal decomposition of polytetrafluoroethylene in various gaseous atmospheres

Abstract

The effects of various gaseous atmospheres on the thermal decomposition of polytetrafluoroethylene have been investigated in the range 450 to 5000 C. Both catalysis and inhibition were observed . The inhibitory substances, chlorine, hydrogen, carbon tetrachloride, and toluene, all produced marked changes in the mechanism of polytetrafluoroethylene decomposition. Whereas the normal degradation reaction in a vacuum produces mainly monomer, the inhibited reactions give large fragments plus side reactions such as the defluorination of the skeletal carbon structure. The results can be interpreted in terms of previous theoretical treatments of chain mechanisms for polymer decomposition and lead to the conclusion that, although the inhibited reactions produce little monomer and are highly random, the relatively high rates observed indicate induced decomposition by the inhibitory substances. Energetic considerations are discussed and appear consistent with the postulated mechanisms.