From Chempedia

Figure 1^[1]

April 6, 1938 was the date of one of the most influential discoveries at the Du Pont research laboratory. Working with a gas related to Freon, Dr. Roy Plunkett and his associates discovered a sample of a white, waxy material that had spontaneously formed after compressing tetrafluoroethylene. The resulting product proved to be one of the most frictionless materials known to man and would go on to be widely marketed under DuPont Teflon in 1945.^[2]

Contents 1 Chemical Properties And How Teflon Works In Pans 2 Uses 3 Harmful Effects 4 In Conclusion 4.1 Footnotes

Chemical Properties And How Teflon Works In Pans

Teflon, also known by the chemical name Polytetrafluoroethylene (PTFE), is a polymer compound of fluorine and ethylene.^[3] A polymer compound is a long molecule with repeating units that are held together by chemical bonds.^[4] Figure 2 shows the PTFE unit that is repeated. The 'R' on each C (carbon) means repeat.

    F   F
    |   |
R - C - C - R
    |   |
    F   F

Figure 2 ^[5]

The carbon atoms in the compound are completely surrounded by the electron cloud of the fluorine atoms. This causes the polymer chain to have no net charge and be non polar, making its chemical reactivity very low. PTFE also has C-F (carbon-fluorine) and C-C (carbon-carbon) single bonds that are very strong and hard to break. Because of this, large amounts of energy are required to break these bonds. Its melting point is 327°C. PTFE has the lowest coefficient of friction of any known solid compound. The coefficient of friction is a scale that is used to measure the force of friction between two materials.^[6] Its low interfacial forces, the forces between the structures surface and other materials, and the compound’s strong bonds cause the low coefficient of friction.^[7] Because of this, PTFE is slippery and nothing sticks to it. It does not even stick to itself. Therefore, substances, such as food, can easily be removed from the surfaces of pans. PTFE adheres to pans because the pan’s metal surface is sandblasted, so it is very rough with edges.^[8] Then a primer is applied, and the Teflon gets embedded into the primer and rough edges of the pan.^[9] It is then baked and dried to become non-stick.

Uses

Teflon’s chemical properties allow it to have a wide range of uses. Of these uses, the most familiar is the use of Dupont’s non-stick cookware. Dupont Teflon improves its non-stick cookware by using three coats: a "unique topcoat - for easy food release and easy cleanup, a tough mid-coat for excellent resistance to scratches and abrasions, [and a] rugged primer-for long-lasting durability." ^[10]

The unique properties of Teflon also allow it to bind to fibers making it an effective stain repellent for fabrics. As a fabric guard, Teflon is useful for fabrics such as upholstery. The stain resistant upholstery is now being used by Laura Ashley, a popular home furnishing company. The fabric can also be used on retractable roofs; for example, the NFL stadium in Houston uses the fabric for its retractable roof that is approximately 400,000 square feet.^[11]

The food processing industry utilizes Teflon because it helps prevent the degradation of tubes and nozzle holders involved in food processing. Teflon is also being used in automotive parts, semiconductor manufacturing, and pharmaceutical and biotech manufacturing.^[12] Teflon is continually being developed and its use will continue to be widespread.

Harmful Effects

Although Teflon has the obvious benefits of convenience with cooking, recent studies have shown there may be some harmful effects on the environment and on people who use the non-stick products. When Teflon is heated, it releases potentially harmful chemicals including its key ingredient, perfluorooctanioic acid (PFOA).^[13] However, most typical uses of Teflon do not use enough energy to release significant amounts of PFOA to be considered dangerous.^[14] The problem is that PFOA does not break down in the environment; therefore it remains free within the atmosphere.^[15] These chemicals can also have harmful effects on people and animals that come directly in contact with them. After Teflon is heated, fumes and particles are released into the air. There have been documented cases where this has caused birds’ lungs to hemorrhage and die. When humans come into contact with these fumes it can give them flu-like symptoms, a condition identified as "polymer fume fever."^[16] These conditions do not occur often under normal usage of Teflon products.

In Conclusion

Despite these findings, there has been little to no action taken to curve the use of Teflon. Most of the general public (almost all whom use this product) is unaware of the possible side affects of Teflon usage due to the fact that there have been limited cases involving severe health effects. Since Teflon plays such an important roll in the convenience of everyday life, usage will continue to thrive as it has since the forties. New Teflon products will continue to be manufactured due to its’ chemical properties.

Footnotes

1. ^ Figure of Teflon. [17] (accessed November 8, 2005)
2. ^ The History of Teflon, DuPont Website. http://www.mindfully.org/Plastic/Teflon/Teflon-HistoryDuPont.htm (accessed September 25, 2005).
3. ^ Wikipedia The Free Encyclopedia. http://en.wikipedia.org/wiki/Teflon (accessed September 25, 2005).# ^ Teflon Home Page. www.teflon.com (accessed September 26, 2005).
4. ^ Wikipedia The Free Encyclopedia. [18] (accessed September 25, 2005).
5. ^ Wikipedia The Free Encyclopedia. [19] (accessed September 25, 2005).
6. ^ Wikipedia The Free Encyclopedia. [20] (accessed September 25, 2005).
7. ^ Wikipedia The Free Encyclopedia. [21] (accessed September 25, 2005).
8. ^ Sally Ride Science Home Page. http://sallyrideclub.com/wondering.do?id=20041022.im.wondering (accessed September 25, 2005).
9. ^ Sally Ride Science Home Page. [22] (accessed September 25, 2005).
10. ^ Teflon Home Page. www.teflon.com (accessed September 26, 2005).
11. ^ Teflon Home Page. www.teflon.com (accessed September 26, 2005).
12. ^ Teflon Home Page. www.teflon.com (accessed September 26, 2005).
13. ^ True Health Home Page. http://www.truehealth.org/ahealn43.html (accessed September 25, 2005).
14. ^ True Health Home Page. [23] (accessed September 25, 2005).
15. ^ Dr. Joseph Mercola, Northwoods Titan Content Management System. http://www.mercola.com/2001/aug/1/teflon.htm (accessed September 25, 2005).
16. ^ Wikipedia The Free Encyclopedia. [24] (accessed September 25, 2005).

Researched and written by: Nariman Vanaki, Cameron Weir, Amy Yang, and Maria Yang.