Polytetrafluoroethylene (PTFE) is a fluoropolymer discovered by Roy J. Plunkett (1910–1994) of DuPont in 1938. It was introduced as a commercial product in 1946.
PTFE has the lowest coefficient of friction (against polished steel) of any known solid material. It is used as a non-stick coating for pans and other cookware. PTFE is very non-reactive, and so is often used in containers and pipework for reactive chemicals. According to DuPont its melting point is 327 °C, but its properties degrade above 260 °C.
Other polymers with similar composition are known with the PTFE: fluorinated ethylene-propylene (FEP) and perfluoroalkoxy polymer resin (PFA). They retain the useful properties of PTFE of low friction and non-reactivity, but are more easily formable. FEP is softer than PTFE and melts at 260 °C; it is highly transparent and resistant to sunlight.
PTFE is either synthesized by the emulsion polymerization of tetrafluoroethylene monomer under pressure, using free-radical catalysts or it may be produced by the direct substitution of hydrogen atoms on polyethylene with fluorine, using polyethylene and fluorine gas at 20 °C
PTFE Encapsulation
Combines excellent chemical and temperature resistance of PTFE o-rings with elasticity of its core material of Viton or Silicone. PTFE FEP Encapsulates (encloses) the core material of either silicone or Viton elastomer.
These O-rings are oil resilient and heat resistant. The PTFE FEP encapsulation provides sealing effect, and the inner elastomer provides constant pressure of the encapsulation to the sealing surface. Good for sealing corrosive fluids. PTFE coating makes them virtually impervious to most solvents and chemicals.
Average total shore A hardness:
85-90 shore A silicone core
90-95 shore A Viton core
The PTFE FEP encapsulation complies with part 177 of Title 21 of the Food and Drug Administration’s regulations for safe use as articles or components of articles for producing, manufacturing, processing , preparing, treating, packaging, transporting, or holding food in accordance with regulation 177.1550
PTFE Encapsulated Silicone Color is clear with a brick red inner ring.
PTFE Encapsulated Viton Offers greater chemical resistance than silicone. Color is clear with a black inner ring.
Temperature range: -75° F to +400° F.
Meets ASTM D2000 2BE720A14B14E14E34F17.
Temperature: -40° to 250° F
Color is black.