Abstract
A series of exceptionally heat-stable thermoplastic fluorochlorocarbons derived from chlorotrifluoroethylene and commercially available under the trade name Kel-F are highly resistant to a large number of chemicals. Their properties make them particularly attractive for use as thermoplastic protective coatings and in the form of molded separators. Some aspects of the development work and results obtained in solving corrosion problems are presented in this article.
The use of diaphragms of this material in Saunders' type valves has solved many difficult commercial operating and corrosion problems. Suitably designed "O" rings and gaskets have solved gasketing problems in some highly corrosive systems. Other similar applications are being studied.
The application of these coatings to protect metal surfaces exposed to corrosive systems is being studied via dispersions of finely divided plastic in a volatile vehicle. Preliminary data on the vapor permeability of the films prepared from dispersion indicate it to be superior to most other plastic films tested.
The performance of the coatings is dependent to a large extent on the molecular weight of the polymer. Molecular degradation of the polymer during the fusion operation and subsequent heat aging is influenced by various metals; in some cases excessive degradation has resulted.
The coatings have been tested in the laboratory with a large variety of corrosive materials and numerous field tests are under way.
