What is Teflon?
Teflon, chemically defined polytetrafluoroethylene (PTFE), is a synthetic polymer of tetrafluoroethylene entirely made up of carbon and fluorine; characterized by a high molecular weight, it shows a completely solid consistency.
Teflon has strong hydrophobic properties, thanks to the high electronegativity of fluorine; moreover, it boasts one of the lowest coefficients of friction currently known (reason for its use in the kitchen as a non-stick coating for pots, pans, dripping pans, utensils, etc.).
Being not very reactive, partly due to the strength of the bonds between carbon and fluorine, it is often used for the production of containers and pipes for very reactive and corrosive chemical liquids.
If used as a lubricant, Teflon reduces friction, therefore the wear and energy consumption of the machines.
Last but not least, Teflon is also used as a grafting material in surgical procedures.
Risks of Pyrolysis
Teflon is best known for its use as a non-stick coating on pans and other kitchen utensils, as it is hydrophobic and highly heat resistant.
However, by letting a Teflon-coated pan be subjected to the flame of a stove, the compound undergoes a degradation proportional to time and specific temperature.
In fact, the pyrolysis (thermochemical decomposition) of Teflon is detectable at 200 ° C (392 ° F) for the generation of various gases and fluorocarbon-based sublimates. Nonetheless, an old animal study (from 1955) concluded: "it is unlikely that, at temperatures below 250 ° C (482 ° F), these products could be generated in significant quantities that could harm the health of the animal organism”.
This means that, while being stable and non-toxic at lower temperatures, Teflon instead begins to deteriorate significantly when these reach around 260 ° C (500 ° F) and probably decomposes strongly above 350 ° C (662 ° F). . These by-products of Teflon pyrolysis have been shown to be lethal to birds and cause flu-like symptoms in humans.
Meat is generally cooked between 204 and 232 ° C (399 and 450 ° F), and most fats start smoking before the temperature reaches 260 ° C (500 ° F). However, remember that there are at least two edible oils that boast a higher smoke point, namely the "refined safflower oil and the "avocado oil (palm, one of the most used in the world, has a smoke point of about 245 ° C).
Risks of Ingesting Teflon
The risk of ingesting Teflon with food is different, but still probable.
This material can hide in food if scraped from the surfaces that contain it by means of metal tools (spatulas, forks, spoons, ladles, etc.); in fact, to prevent this from happening, it is advisable to use specially designed tools made of softer materials.
Although it is in any case sufficient to avoid vigorously rubbing the non-stick Teflon cooking utensils in order not to ingest any fragments, it is however necessary to specify that the very small parts possibly taken with food do not undergo any digestion and / or absorption; in other words, they pass through the digestive tract and are totally expelled with feces.
Perfluorooctanoic acid
L"perfluorooctanoic acid (PFOA) is a chemical element sometimes used in the production of Teflon; this would be used as a surfactant in the polymerization of certain Teflon emulsions (mixtures). Currently, many manufacturers have completely discontinued its use, as it tends to persist indefinitely in the environment and is toxic-carcinogenic to animals.
PFOA has been detected in the blood of over 98% of the general population of the United States and its levels are highest in chemical plant workers as well as the surrounding population.
Americans' exposure to perfluorooctanoic acid is mainly due to the dumping of waste into the ocean and near the Ohio River valley over the past fifty years.
PFOA is detectable in industrial waste, stain resistant carpets, carpet cleaning fluids, anti-dust products, microwave popcorn bags, water and food themselves, and some non-stick cookware which obviously contain Teflon enriched with perfluorooctanoic acid.
As a result of a class-action (mass lawsuit) against "DuPont", three epidemiologists have conducted some studies on the population surrounding a chemical plant that has been exposed to higher levels of PFOA than the general population. The investigations concluded that there is probably a "direct association" between PFOA exposure and six types of health impairment, such as: kidney cancer, testicular cancer, ulcerative colitis, thyroid disease, hypercholesterolemia and hypertension in pregnancy.
On the other hand, considering the health implication linked to the use of non-stick Teflon pans with greater specificity, this is considered completely insignificant.
Property
Teflon is a thermoplastic polymer, with a solid consistency and white color (at room temperature); its density is about 2200 kg / m3. According to "DuPont", the melting point is 327 ° C (620 ° F); at -268.15 ° C (-450.67 ° F) it maintains a "high strength, toughness and self-lubrication, while at temperatures above -79 ° C (-110 ° F) it also has good elasticity.
The friction coefficient of Teflon (measured on liquid steel) is between 0.05 and 0.10, which is the lowest third of any known solid material (after the "Aluminum Magnesium Boride and the Diamond Like Carbon). Teflon cannot be crosslinked like an elastomer, has no "memory" and is often used as a gasket material.
Other Applications
The main application of Teflon (50% of production) is in the wiring of aerospace and computer applications, for example the connection of wires, coaxial cables etc.
In industrial applications it is used where a sliding action is required, such as joints, gears, sliding plates, etc.
Teflon film is also widely used in the production of carbon fiber and glass fiber composites, on which it is interposed to prevent materials from sticking.
