Free energies of formation of fluorocarbons and their radicals. Thermodynamics of formation and depolymerization of polytetrafluoroethylene

Abstract

Abstract Enthalpies and free energies of formation of a group of aliphatic fluorocarbons and their radicals for 298.15°K. and the ideal gaseous condition are calculated from the available experimental heat and entropy data, extended by means of empirical series treatments. The polymerization of tetrafluoroethylene and the thermal breakdown of the resulting polymer are recognized as thermodynamically equivalent processes, differing only in the sign of the thermal quantities involved. Free energy changes attending various intermediate steps in the free radical‐initiated polymerization are calculated. The heat and free energy of polymerization are highly exothermal at 298.15°K., compared with those for other olefinic compounds. At high temperatures reversal of the synthesis steps is to be expected. Initiation of degradation need not occur merely by reversal of the termination process, although this possibility is not excluded.