The Evolution of Hydrogen Fluoride from Hydrofluoro-Elastomers

Summary

Hydrofluoro-elastomers comprise one of the most thermally stable elastomer systems currently available. Because of their chemical structure, there is the possibility of elimination of hydrogen fluoride from the polymer chains at elevated temperatures. This is analogous to the splitting out of hydrogen chloride from poly(vinyl chloride). If the hydrofluoro-elastomers are used as seals, or sealants, in contact with metals such as titanium, the presence of hydrogen fluoride may cause stress corrosion cracking. The available data on the evolution of hydrogen fluoride from hydrofluoro- elastomers are reviewed. It is shown that the type of formulation used in producing a practical rubber system is critical in this respect. Although substantial advances have been made in solving the technological aspects of the problem, there are still many unanswered questions relating to the mechanisms of the various processes involved.