Method for producing expandable graphite intercalation compounds using phosphoric acids, and graphite foil

Abstract

A method for producing expandable graphite intercalation compounds uses a thermal polyphosphoric acid which is added to an intercalation agent or to graphite. Preferably, the thermal polyphosphoric acid is used in a mixture with red, fuming nitric acid. Products produced from the graphite intercalation compounds through the expanded graphite stage, such as graphite foils, graphite laminates or graphite seals, have a comparatively high fluid tightness, are relatively resistant to oxidative attack, and can have comparatively high strengths. A further advantage is a good handling ability of the thermal polyphosphoric acids. A graphite foil is also provided.

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