Polytetrafluoroethylene


The discovery of polytetrafluoroethylene, (PTFE) was accidentally made by Roy Plunkett working for Kinetic Chemicals in 1938 on April 6th. Roy was using the gas, tetrafluoroethylene in a the manufacture of a new refrigerant. During one experiment the pressure of the gas bottle containing tetrafluoroethylene stopped flowing before its weight signalled that it was empty. The gas could not have just disappeared so Roy out of curiosity sawed the bottle apart.

Inside the bottle was a white waxy substance that was slippery to the touch. Instead of dismissing the finding, Roy sent this material for analysis. The results showed that it was a polymerised perfluoroethylene, (that is many groups of perfluroethylene joined together by chemical bonds), and it was surmised that the iron inside the gas container acted like a catalyst under high pressure.

Polytetrafluoroethylene Formation, Source: Wikimedia Commons

Kinetic Chemicals decided to patent this new fluorinated plastic in 1941 and registered the Teflon trademark in 1945. An early use for Teflon was as a material to coat the valves and seals in pipes at the K-25 uranium enrichment plant Oak Ridge, Tennessee that held the highly reactive uranium hexafluoride. This is because as well as being slippery, Teflon is non-reactive. Another use of Teflon is as a lubricant. Its slippery nature reduces friction, wear and energy consumption in machinery.

By 1948, DuPont, the founder of Kinetic Chemicals was producing over 900 tons of Teflon per year. At this time though, it had not been introduced to the kitchen so people still needed to know how to fry an egg without it sticking to the fry pan. I argue that this is an important skill to have regardless!

Teflon is used as a coating on pans and other cookware including utensils. Its non-reactive properties and heat resistance makes it an ideal coating. The first Teflon coated pan was produced in 1954 by French engineer, Marc Grégoire under the brand name Tefal after his wife urged him to try the material he was using on his fishing tackle on her cooking pans. In 1961, American inventor, Marion A Trozzolo who had been using Teflon on scientific equipment marketed the first USA made Teflon coated frying pan, dubbed “The Happy Pan“.

The coefficient of friction of plastics is measured against polished steel. Teflon’s coefficient friction is 0.05-0.10 which makes it the third lowest of any known solid material. It means that Teflon is very slippery and this slipperiness is due to a resistance to van der Waals forces. It is so slippery that it is the only known surface to which a gecko cannot attach to.

About these ads

3 Comments

Filed under chemistry365, Science

3 responses to “Polytetrafluoroethylene

  1. markuspaul

    what was written about Polytetrafluoroethylene is suggest me beautiful information but i found many other blog that suggest me that using teflon cookware, worrying news today about the high levels of a potentially carcinogenic chemical, which is found in most of our kitchens.So that More than 55% of cancers occur in people aged 65 years or older. A number of studies have found that older patients are less likely to receive a comprehensive treatment for their cancer.

    • Without knowing what this carcinogenic material is, it is difficult to respond to your comments.

      As for the rate of cancers in older people, what is your source for this statistic and what was it in reference to? The rates of cancers varies amongst different groups of people for a whole host of reasons.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s