Thermal degradation of polymers. I. Aspects of polytetrafluoroethylene degradation

Abstract The mechanism of the thermal degradation of polytetrafluoroethylene is investigated. It is shown that the chain transfer reaction should not be ignored and that a reasonable explanation for the observation that monomer is almost the exclusive product of vacuum thermal degradation is the rate of diffusion and volatilization of larger fragments from the polymer. Diffusion of tetrafluoroethylene and hexafluoropropylene through polytetrafluoroethylene was studied. The diffusivities are 72 and 39 × 10 −10 cm. 2 /sec. for C 2 F 4 and C 3 F 6 , respectively, at 24°C. An apparatus for measuring the weight and temperature of degrading polymers under vacuum is also described.