Nomenclature
CAS number: 9002-84-0
Tetrafluoroethene homopolymer; tetrafluoroethylene polymer; polytetrafluoroethylene resin; polytef; PTFE; Fluon (ICI); Teflon (DuPont); Tetran (Elf Atochem).
Description and references
A highly stable thermoplastic tetrafluoroethylene, q.v., homopolymer.
Composed of at least 20,000 C2F4 monomer units
linked into very long unbranched chains. Prepd by polymerization
of tetrafluoroethylene: Plunkett, US 2230654 (1941 to Kinetic Chem.); Brubaker, US 2393967; Joyce, US 2394243 (both 1946 to du Pont); Hanford, Joyce, J. Am. Chem. Soc. 68, 2082 (1946); Renfrew, US 2534058 (1950 to du Pont); C.
E. Schildknecht, Vinyl and Related Polymers (Wiley, New York, 1952) pp 483-494. Account of discovery by Roy
J. Plunkett: A. B. Garrett, J. Chem. Educ. 39, 288 (1962). Reviews: M. M. Renfrew,
E. E. Lewis, Ind. Eng. Chem. 38, 870-877 (1946); R. W. Moncrieff, Man-Made Fibres (John Wiley, New York, 4th ed., 1963)
pp 512-517; McCane in Encyclopedia of Polymer
Science and Technology vol. 13, N. M. Bikales,
Ed. (Interscience, New York, 1970) pp 623-654; S. V. Gangal in Kirk-Othmer Encyclopedia of Chemical Technology vol. 11 (Wiley-Interscience, New York, 4th ed., 1994)
pp 621-644.
Properties
Nonflammable, high polymer. White translucent
to opaque solid (depending on thickness). Very inert chemically.
Useful temp range from cryogenic to +260°. Melts
to an extremely viscous gel at 327° and
reverts to the gaseous monomer at temperatures above 400°. d 2.2. Shore hardness
55-56. Tensile strength 3500-4500 psi. Flexural modulus ≈80,000-90,000
psi at room temp. Brittle point below -80°. Dielectric constant
(at 60 to 3 × 109 cycles) 2.0-2.05. Not affected by water,
aqua regia, chlorosulfonic acid, acetyl chloride, boron fluoride,
hot nitric acid, boiling solns of sodium hydroxide, and organic solvents.
Not wetted by water. No substance has been found which will dissolve
the polymer at moderate temperatures, but prolonged contact with fluorine,
hot plasticizers and polymeric waxes is not recommended. Is subject
to cold flow at high pressure. Because of its high melt viscosity
molding and sintering techniques similar to those used in powder metallurgy
are normally used for fabrication.Caution
Potential symptom of overexposure
by inhalation to the heated polymer is polymer fume fever, characterized
by dizziness, headache, nausea, chills, weakness, cough, chest tightness,
sore throat, pyrexia. See Clinical
Toxicology of Commercial Products, R. E. Gosselin et al., Eds. (Williams & Wilkins, Baltimore, 5th ed., 1984)
Section II, p 412; Patty's Industrial Hygiene
and Toxicology vol. 2E, G. D. Clayton, F. E.
Clayton, Eds. (John Wiley & Sons, New York, 4th ed., 1994) 3791-3793.Use
For hookup and hookup-type wire in electronic equipment;
in computer wire, electrical tape, electrical components, spaghetti
tubing. Seals and piston rings, basic shapes, bearings, mechanical
tapes, coated glass fabrics. As tubing and sheets for chemical laboratory
and process work; for lining reaction vessels; for gaskets and pump
packings, sometimes mixed with graphite or glass fibers; as electrical
insulator esp in high frequency applications; filtration fabrics;
protective clothing. Prosthetic aid.