Virgin PTFE sheet from AK Rubber has the following properties.
Excellent resistance to continuous service temperatures up to 260 oC and, for limited periods, even to higher temperatures; the low temperature resistance of the product allows satisfactory performance at as low as -200 oC.
PTFE Processes a high inertness towards nearly all known chemicals. It is only attacked by elemental alkali metals, chlorine trifluoride and elemental fluorine at high temperatures and pressure
PTFE is insoluble in all solvents up to temperatures as high as 300 oC (572oF) Certain highly fluorinated oils only swell and dissolve PTFE at temperatures close to the crystalline melting point.
FDA Approved (Code of federal regulation 21 CFR Ch.1 revised as of April 1st 1991 edition), Sections 175.105 – 175.300 – 176.170 – 176.180 – 177.1520 – 177.1550 – 177.2600 – 178.3570. “Perfluorocarbon Resins” of the Food and Drug Administration