Teflon: the History and Story of a Slippery Beginning
This is the story of a farm boy made good. Roy J. (Joseph) Plunkett (1910-1994) was born in New Carlisle, Ohio. He attended and graduated from Newton Township High School in Pleasant Hill, Ohio. In 2007, he was inducted into the Newton High School Hall of Fame.
Plunkett majored in chemistry and got a Bachelor’s degree from Manchester College in Indiana, a Christian liberal arts school. It seems that “like minds” attract; Plunkett’s roommate at Manchester was Paul Flory, who said his remarkable professor of chemistry, Carl W. Holl, kindled his interest in science and chemistry. Flory went on to win a Nobel Prize for chemistry in 1984 for his discovery and its impact with polymers. Flory got his doctorate at Ohio State University. Plunkett, a chemistry high achiever, received his Master’s there too, and a Ph.D. in organic chemistry in 1936.
DuPont hired Flory. Soon after graduating, Plunkett came on board. Plunkett was appointed research chemist for the American division of that giant company too—Compagnie du Pont de Nemours & Company—(DuPont) in Deepwater, New Jersey; he worked in the Jackson Laboratory.
Since 1909, General Motors Corporation (GM) had been looking for a safe refrigerant. Their directive was to develop and commercialize chlorofluorocarbon (CFC) chemicals, gaseous compounds that are used in applications where things needed to be kept cold. For use in a refrigerator, they needed to replace dangerous ammonia, sulfur dioxide and propane. Ultimately, GM’s skills were in machinery not chemicals, so they looked to DuPont for a solution.
In 1930, DuPont and General Motors created a joint venture called Kinetic Chemicals Inc. The ideal refrigerant to DuPont’s way of thinking was to have it possess thermodynamic properties (heat and temperature to create energy), be noncorrosive to other machine components and be free of toxicity and flammability. DuPont eventually named the brand, Freon. First, there were two CFC’s created, named Freon 112 and 113. The partnership fell away and DuPont went looking for their own refrigerant. They came up with Freon 114.
Plunkett’s Eureka! Moment
In 1938, two years after Roy Plunkett joined the giant American chemical company, he was still looking for the company’s safe refrigerant. The current inherent chemicals –ammonia and sulfur dioxide-- were still too dangerous for use in the home.
Plunkett started using a chemical called tetrafluoroethylene or TFE that was compressed into tanks. He once stored the chemical overnight in dry ice to keep the gas from expanding too much and exploding. When nothing came out of the tank during the cooling-fluid experiment the next day, Plunkett assumed that the gas had leaked out. The only way to check his theory was to put it on a scale and weigh it. Funny, but the tank weighed the same as when it was full.
He and an assistant tried to unclog the valve to the tank with a long wire thinking it was stuffed up and prevented the substance from coming out. Nothing. Finally, Plunkett decided to open the tank and unscrewed the lid. A bunch of white waxy flakes fell out. He and his assistant sawed the tank in half, and the inside of the tank was coated with the same slippery stuff. The material had polymerized.
Plunkett surmised that the tiny gas molecules had joined to make a long chain so he named it “polytetrafluoroethylene” (PTFE).
Deciding to examine the waxy substance, Plunkett put it under some tests. He later told his wife that he was initially disappointed, thinking the experiment a complete flop. When he made a decision to test the material anyhow, he attacked it with a vengeance. He heated and froze it. Then he began digging in the cupboard to find chemicals to check its other properties.
In addition to being slippery, the glob was unfazed by other powerful chemicals, and unchanged by searing acids. The best part though, came after he dipped a plastic rod covered with the stuff into an acid. The rod dissolved in the corrosive material but did not change the white waxy coating. It also had a low surface friction so it would not stick to anything.
DuPont christened it Teflon and trademarked it in 1945. Plunkett was awarded the patent for it in 1941. Plunkett would later tell students that his mind had been prepared for the challenge by years of education, and that he had succeeded because he was trained to recognize novelty.
Teflon as a consumer product is interesting on its own. A Frenchman named Marc Grégoire was looking for something to keep his fishing gear from getting tangled and discussed Teflon with his wife Collette. She went one better and suggested that nonstick pans would be more useful. They called the coating “Tefal” and started production in 1954. The early French advertisement said, “Nothing sticks to Tefal.” The majority of pots and pans sold in the United States today are coated with one of Teflon’s cousins.
Soon Teflon revolutionized the plastics industry. In 1976, a scientist named Robert Gore co-invented a technique to expand PTFE and bind it into microstructures called Gore-Tex. This led to other applications such as stain-repellant solutions for carpets, clothing and furniture. It is also found in plumber's tape because it creates watertight seals in pipe joints. Because of its heat-bearing properties, it is used in O-rings and bearings, and as heavy-duty insulation for electronic wiring and cables. These characteristics make it perfect for coating barrels and bottles that contain corrosive industrial materials. Finally, PTFE is an essential component of dental floss!
Government and Military Teflon
Teflon was used for military nose cone material on proximity bombs and in artillery shell fuses. Its best asset for these applications: it was transparent to radar. One of the other military uses was in the production of nuclear material used in the Manhattan Project, America’s top-secret plan to build an atomic bomb.
Other uses sprang up, such as in the suits that astronauts wore. For example, as part of the U.S. Apollo program, astronauts donned thick pressure suits that had 25 layers of fabric and plastic. The outer layer was created from Teflon fibers that not only stopped from friction and wear, but also acted as a protectant against fire.
Roy Plunkett’s Legacy
Even though Roy Plunkett was known for his discovery of Teflon, he later went into management at DuPont, eventually becoming the Director of Operations, Freon & Organic Chemicals Division. He retired in 1975, after almost 40 years of service in Wilmington, Delaware.
He won these awards:
- Franklin Institute's John Scott Medal 1951
- NAM Modern Pioneer Award 1965
- AIC Chemical Pioneering Award 1969
- Plastics Hall of Fame 1973
- Moissan Award for Fluorine Chemistry 1986
- SPE John W. Hyatt Award 1988
- National Inventors Hall of Fame 1985
DuPont honored him with an award in his name, first given in 1988 to celebrate the 50th anniversary of his discovery of Teflon. The Plunkett Award recognizes those who contribute to creating important new products using Teflon.
Before his death, Plunkett said he was pleased to be credited with an invention that “…has been of great personal benefit to people—not just indirectly, but directly to real people whom I know.”
Roy J. Plunkett died of cancer in 1994.