Teflon: a happy accident that shaped world history
In this blog entry I will discuss the discovery and invention of a technology everyone knows and most of us have used. The history of this product is fascinating. I believe that the course of world history may have been changed by this invention in a way that almost none of my readers is likely to be familiar with.
The discovery of Teflon™ is an example of serendipity. Serendipity means a kind of “happy accident” – an unintended discovery. In our story, the chemical firm, DuPont, and General Motors (GM) were collaborating to develop improved refrigerants. GM was not just interested in automobile air conditioning; they had also owned the home and industrial refrigeration firm, Frigidaire, for about sixty years. Early refrigeration units used costly (and potentially hazardous) coolants, including propane, ammonia, and sulfur dioxide. The two companies teamed up to form Kinetic Chemicals and evaluated various chlorofluorocarbons (CFCs) we often refer to as Freon.
Freon 114 was put into mass production for GM, which used 100% of DuPont’s output. In the late 1930s, DuPont needed to develop another refrigerant it could sell to other companies. They hired Roy Plunkett, who had just completed his Ph.D. at Ohio State.
One of Plunkett’s experiments involved reacting tetrafluoroethylene (TFE—a colorless, odorless gas made from chloroform) with hydrochloric acid. The concoction was stored in metal cylinders and kept on ice to minimize the risk of explosion. Plunkett’s assistant connected one of these cylinders, in which about 100 pounds of the new material was stored, to the test apparatus and found that nothing would flow out of the cylinder. The pressure in the cylinder had dropped to zero! There was no leak— the cylinder weighed just what it had weighed previously. Plunkett sawed open the cylinder and discovered a slippery material with fascinating physical properties.
DuPont followed up on this discovery with research on its potential applications and ways to manufacture it at a commercial scale. The timing was right for an application known then as polymerized tetrafluoroethylene (PTFE). Few of us think of this term when we use a Teflon™ coated frying pan!
But frying pans aren’t the impact on “the course of world history” that I promised you! The largest secret industrial project during WWII was the Manhattan project. The idea of building an atomic bomb to counter the potential threat of a German device was initiated in 1939 before the US had entered the war. Albert Einstein, Enrico Fermi, Leó Szilárd and others urged the US to pursue the development, but only in 1941 were the first steps of the Manhattan project taken. In December 1942, the first controlled nuclear chain reaction took place under the west stands of the Amos Alonzo Stagg field at the University of Chicago. Today’s Stagg field seats fewer than 2,000 people, but the nearby Stagg field of 1942 seated 50,000.
After this successful test, money flowed freely, and massive parallel projects in Oak Ridge, Tennessee, Hanford, Washington, and Los Alamos, New Mexico, were rapidly designed and constructed. The population around the Oak Ridge buildings grew from a few thousand to 75,000 in a few years, and the largest building in the world — K-25 — was constructed. Among other goals at Oak Ridge, significant quantities of U-235 had to be separated from the dominant U-238 isotope. U-235 is slightly lighter than U-238, and uranium hexafluoride gas (UF6) can be processed from uranium ore relatively easily. The gas diffusion process used in Oak Ridge required enormous numbers of vessels and filters and consumed a great deal of electrical power. This process has since been replaced by techniques involving centrifuges.
UF6 (known as “hex”) is highly corrosive. It would destroy conventional seals, fittings and valves. As it turns out, DuPont was selected to design the gaseous diffusion plant at Oak Ridge. PTFE was used to coat the piping and valves and eliminated the corrosion problems. Without PTFE, some have argued that the development of the atomic bomb would have been delayed at least an additional six months. Such a delay could have caused the US to pursue a direct attack on the Japanese mainland. This, of course, would have massively changed the course of history.
Furthermore,US military planners seriously evaluated the use of atomic bombs in the Korean conflict but refrained for, among other things, the lack of an ideal target. If nuclear technology had not been proven in Japan, the temptation to use the devices in Korea may have led to their use there. Thus, Teflon truly played a role in changing world history.
DuPont reserved 100% of their PTFE production for the military, with the majority of it going to Oak Ridge. Following the war, DuPont pursued numerous applications of the promising chemical. The name, Teflon, was trademarked in 1944. It saw widespread applications once DuPont devised ways to produce it in quantity at reasonable prices. The idea of using it on frying pans had occurred to DuPont but concerns about consumer perceptions of safety delayed the introduction.
A French engineer learned about a new way to apply the material and coated his fishing tackle with it to prevent snags. His wife encouraged him to try it on a frying pan, with great success. They formed a company to produce Tefal™ brand pans. Millions of non-stick pans were soon being sold with Teflon coatings. Unfortunately, some of the pans were improperly designed and the reputation of coated pans was damaged.
Today Teflon is used widely in a variety of applications and has even become an adjective meaning “non-stick”, or “slippery”, when applied to describe people whose errors or poor decisions damage their reputations.
Baker Hughes manufactures a line of specialty polymers and waxes called Polywax™, which are excellent alternatives to PTFE in certain applications such as in ink applications. They offer excellent resistance to solvents and abrasion and provide early adhesive bond strength and improved toner transfer.
There were many sources for this blog including these (1) (2) and (3) with this one being the most interesting. One source credits the Summer 2000 issue of American Heritage magazine. However, there is no such edition in their online archives.