Title: Polytetrafluoroethylene
CAS Registry Number: 9002-84-0
CAS Name: Tetrafluoroethene homopolymer
Additional Names: tetrafluoroethylene polymer; polytetrafluoroethylene resin; polytef; PTFE
Trademarks: Fluon (ICI); Teflon (DuPont); Tetran (Elf Atochem)
Literature 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.
Melting point: Melts to an extremely viscous gel at 327° and reverts to the gaseous monomer at temperatures above 400°
Density: d 2.2
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. |