What is PTFE (Polytetrafluoroethylene)? | The Complete Guide (2023)

What is PTFE (Polytetrafluoroethylene)? | The Complete Guide (1)

PTFE or polytetrafluoroethylene is a high-performance and versatile fluoropolymer made up of carbon and fluorine atoms. A fluoropolymer is a group of plastics offering a wide array of properties and benefits. PTFE is one such fluoropolymer, and its discovery reformed the fluoropolymer group forever and paved the way for several applications.

One of the common applications for PTFE material includes non-stick coatings for kitchen cookware. Thanks, to its non-reactive nature, partly because of the strength of carbon-fluorine bonds, it is often utilized for making pipeworks and containers for reactive and corrosive chemicals.

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How is PTFE Made?

What is PTFE (Polytetrafluoroethylene)? | The Complete Guide (2)

The making of PTFE is quite similar to any other polymer. It is manufactured by the free-radical polymerization technique in an aqueous media using the addition polymerization of TFE in a batch process.

The chemical structure of PTFE is identical to polyethylene; the only major difference is that the hydrogen atoms are completely replaced by fluorine. However, the preparation methods for PE and PTFE are drastically different from each other.

The size of the fluorine atom is huge, and that forms a uniform and continuous sheath around carbon-carbon bonds and hence provides good chemical resistance, electrical inertness, and stability to the molecule.

The Interesting History of PTFE –

What is PTFE (Polytetrafluoroethylene)? | The Complete Guide (3)

Like many other great discoveries, PTFE was found accidentally. Roy J. Plunkett first discovered it in 1938. At the time, he was working in new jersey for Dupont. Plunkett’s original purpose was to make a new chlorofluorocarbon refrigerant. However, the tetrafluoroethylene gas in its pressure bottle stopped flowing before the bottle’s weight had gone to the point signaling “empty.”

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But as Plunkett measured the amount of gas used by weighing the bottle, he became interested in the source of weight and finally decided to split the bottle apart.

He found the interior of the bottle coated with a white waxy, and slippery material. Later it was named polymerized perfluoroethylene, and the iron from the container’s inside acted as a catalyst.

The new material was patented by kinetic chemicals in 1941 as new fluorinated plastic and registered the Teflon trademark in 1945. Fast forward to the year 1961, when the first US-made PTFE-coated pan was marketed in the United States as “The Happy Pan.” Since then, there is no looking back, and non-stick cookware has been one of the most common household products produced by thousands of manufacturers and available worldwide.

Interesting Read –

Characteristics and Properties of PTFE –

What is PTFE (Polytetrafluoroethylene)? | The Complete Guide (4)

PTFE is mainly available in three forms – granule, water-based dispersions, and fine powder.

  • The granular PTFE materials are produced by suspension polymerization in an aqueous medium with a meager or no dispersing agent. The granule PTFE material is mainly used in compression, isostatic, and ram extrusion methods.
  • Water-based PTFE dispersions using the same aqueous polymerization using more amount of dispersing agents with agitation. Water-based dispersions are mostly used in coatings ad film casting methods.
  • The fine powder PTFE are small, white particles made by controlled emulsion polymerization. Fine PTFE powders can be processed into thin sections by paste extrusion or additives to improve wear resistance.

Other salient properties of PTFE are excellent high and low heat resistance, electrical insulation properties, chemical inertness, low coefficient of friction (static 0.08 and dynamic 0.01), and non-stickiness over a wide range of temperatures (260 to 260°C).

  • PTFE is one of the most reliable materials in terms of chemical resistance. It is only attacked by molten alkali metals, organic halogenated compounds like chlorine trifluoride (ClF3) and oxygen difluoride (OF2), and gaseous fluorine at high temperatures.
  • The mechanical property of PTFE is also impressive but interior to other engineering plastics at room temperature. The addition of fillers has been proved as a successful way to overcome that obstacle. In its normal temperature range, PTFE exhibits some useful mechanical properties. Those properties are also hindered by processing variables such as sintering temperature, preform pressure, cooling rate, etc. Polymer attributes like molar mass particle size and particle size distribution can negatively impact mechanical properties.
  • Polytetrafluoroethylene has outstanding electrical insulating properties, low dielectric constant, and insulation pressure. The very low dielectric constant (2.0) is a result of a sophisticatedly symmetric structure of macromolecules.
  • PTFE material also shows good thermal properties without obvious degradation below 440 °C.
  • It is also attacked by air degradation and radiation, which begins at a dose of 0.02 Mrad.

Below is a table showing the specific properties and value of PTFE.

PropertyUnit
Melting Temperature (°C)320 to 340
Elongation at Break (%)300-550
Tensile Modulus (MPa)550
Surface Energy (Dynes/g)18
Dynamic Coefficient of Friction0.04
Dielectric Constant2
Refractive Index1.35
Dielectric strength (kV/mm)19.7
Appl. Temperature (°C)260

Engaging Read –

Disadvantages of PTFE Material –

The traditional PTFE material doesn’t come without some drawbacks. Here are they:

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  • Creep and abrasion sensitive
  • It can’t be processed in molten state processing methods, and the suitable methods can often come as unconventional and expansive.
  • Joining difficulties
  • High dimensional variation around glass transition temperature.
  • Low radiation resistance
  • Corrosive and prone to toxic fumes.

Importance of Fillers and Additives for PTFE –

The addition of fillers and additives can significantly improve PTFE’s mechanical properties, specifically creep and wear rate. The common fillers used are steel, carbon, glass fiber, carbon fiber, graphite, bronze, steel, etc.

Glass Fiber: Its addition will improve the creep performance and wear attributes of PTFE by affecting its low and high temperatures. Furthermore, Glass-filled compounds perform exceptionally well in oxidizing environments.

Carbon Fiber: Carbon fibers are essential in lowering creep, raising hardness, increasing flex, and a compressive modulus. The PTFE blended with carbon fiber compounds has high thermal conductivity and a lowers coefficient of thermal expansion. Carbon fiber is inert to strong bases and hydrofluoric acids (Glass fiber can withstand both). These parts are perfect for making automotive parts like shock absorbers.

Carbon: Carbon as an additive will help in reducing creep, increasing hardness, and improving the thermal conductivity of PTFE. The same results can also be achieved by blending PTFE and graphite with elevating the wear resistance of carbon-filled compounds. These blends are ideal for non-lubricated applications like piston rings found in compression cylinders.

Bronze-filled PTFE: This compound exhibits outstanding thermal and electrical conductivity making it perfectly suited for applications where apart is subjected to extreme loads and temperatures.

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Advantages of Incorporating Fillers –

  • Fillers/additives are crucial for increasing the porosity of PTFE compounds and thus affect electrical properties – it decreases the dielectric strength while increasing the dielectric constant and dissipation factor.
  • Fillers can improve the properties of PTFE substantially in both high and low temperatures.
  • The changes in chemical property can highly depend on the type of additive used, but. in general, it also leaves positive results.

PTFE Applications –

In general, fluorinated thermoplastics are utilized for high-performance applications with high heat, high purity, low temperatures, chemical inertness, non-sticking, and self-lubricating properties. Below are some of the most common PTFE uses:

Engineering bearing, non-stick surfaces, seats, plugs, fittings, valve, and pump parts.

Medical – heart patches, cardiovascular grafts, ligament replacement.

Chemical Industry –pumps, diaphragms, impellers, Coatings for heat exchangers, autoclaves, reaction vessels, tanks, containers, etc.

Automotive – valve stem seals, shaft seals, gaskets, O-rings, linings for fuel hoses, power steering, transmission, etc.

(Video) Polytetrafluoroethylene (PTFE)

Electrical & Electronics –flexible printed circuit boards, electrical insulation, etc.

Best Techniques to Process PTFE –

PTFE’s rigid polymer chain structure makes it extremely difficult to process conventional methods like injection molding and extrusion. Still, its very high melt viscosity and high melting temperature also don’t help at all. Processing technologies ideally dealing with powder metallurgy are well suited for PTFE.

  • Sintering, compression molding, pressing, ram or paste extrusion, hot stamping, machining, extrusion of pre-sintered powders on special machines.
  • Paste extrusion, which blends PTFE with hydrocarbons, is used to fabricate it into tapes, tubes, and wire insulation. The hydrocarbon will vaporize before the part is sintered.
  • Operating range -200°C to 260°C.

Engaging Read –What is PVDF (Polyvinylidene Fluoride) | A Detailed Guide

The Future of PTFE Material –

According to a leading market research company ResearchAndMarkets, the global polytetrafluoroethylene market will see a CAGR of 5.13% during the forecast period of 2019-2024.

However, the road will be full of hurdles because of the Covid-19 pandemic. As of writing this piece, the world has re-opened again after a prolonged lockdown, and a vaccine is also making the rounds of the world, but the prolonged shutdown effect will be long felt as the global economy is seeing its worst economic recession in the history of humanity.

Having said that, it’s not all doom and gloom; as the vaccine has been made and people are getting vaccinated rapidly, things can catch up faster than previously anticipated. The same can be said about the PTFE market, let alone the plastic processing industry.

The key for rapid growth lies in the Asian market; China is already the world’s largest consumer of PTFE and still has immense growth potential. Apart from China, countries like India, Indonesia, Japan, Korea, and Bangladesh hold significant potential for future growth thanks to rising household incomes and favorable government policies to trim down the economic adversities caused by the Covid-19 pandemic.

FAQs

1. Is PTFE carcinogenic?

Ans. It has been proven that PTFE is toxic to human health because it contains a carcinogenic substance called PFOA. However, there is no need to worry as PTFE non-stick coatings do not include that substance anymore.

2. What is PTFE tubing used for?

Ans. PTFE tubing is most commonly used as laboratory tubing, where chemical resistance and purity are the most important. PTFE has an extremely low coefficient of friction and is known as one of the most “slippery” substances known.

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3. What type of plastic is PTFE?

Ans. PTFE is a thermoplastic polymer belonging to a fluoropolymer made up of carbon and fluorine atoms.

4. What are PTFE sheets used for?

Ans. PTFE sheets are used in various applications, such as PTFE envelope gaskets and PTFE packings. It comes with an exceptional ability to resist gases, water, chemicals, fuels, and oil.

5. Is PTFE FDA approved?

Ans. PTFE is FDA approved and thus used in the food processing and service industry as insulators and bearings.

Suggested Read –

  • What is LDPE? | Low-Density Polyethylene | The Complete Guide
  • What is Nylon? | Different Types of Nylon | How is Nylon Made? | Key Properties | Applications
  • What is TPV Material? | A Simple and Detailed Guide
  • What is TPE Material? | The Definitive Guide
  • What is PETG Material? | The Definitive Guide
  • What is PEEK Material? | A Simple and Detailed Guide
  • What is UHMW Plastic Material? | The Definitive Guide

Final Thoughts –

That was all I had to say about PTFE plastics. Polytetrafluoroethylene, with its salient properties, should be a good choice for plastic manufacturers. Only powder form processing might be a drawback for many, but it doesn’t come without its perks.

Thanks for reading. Kindly share your thoughts in the comment box.

Have a Fantastic Day.

(Video) How to apply TEFLON (PTFE) TAPE the Proper Way! (full video in description)

FAQs

What is PTFE? ›

Polytetrafluoroethylene (PTFE) is a synthetic fluoropolymer of tetrafluoroethylene. Being hydrophobic, non-wetting, high density and resistant to high temperatures, PTFE is an incredibly versatile material with a wide variety of applications, though it's perhaps best-known for its non-stick properties.

What is polytetrafluoroethylene PTFE used for? ›

PTFE's beneficial properties enable it to be used in a wide range of applications, such as seals (including PTFE 'O' rings), PTFE gaskets, valves, wire insulation, insulated transformers, bearings, surface coatings, chemical processing equipment, chemical transport and PTFE rubber diaphragms – to name but a few.

What is PTFE made of? ›

Polytetrafluoroethylene, also known as Teflon®, is made with four ingredients — fluorspar, hydrofluoric acid, chloroform, and water, which are combined in a chemical reaction chamber heated to between 1094-1652°F (590-900°C). Creating PTFE involves 2 main phases and a series of reactions.

What's the difference between PTFE and PTFE? ›

What's the difference between Teflon™ and PTFE? There is NO DIFFERENCE. They are both exactly the same thing, the only difference between them is the name.

Is PTFE a type of plastic? ›

It isn't metal, it isn't rubber, and it also isn't exactly plastic. More specifically, PTFE is a thermoplastic polymer primarily characterised by a slippery surface, high melting point, and resistance to “attack” by almost all chemicals.

Is PTFE harmful to humans? ›

Remember that PTFE is an inert substance. It can't harm you.

What is the common name for PTFE? ›

Polytetrafluoroethylene (PTFE) is a fluoropolymer and is commonly known by its trade name, Teflon®. Unique properties of PTFE include nonreactivity, hydrophobicity, a low coefficient of friction, and good insulating properties. It is most commonly used as a nonstick coating for cookware.

How toxic is PTFE? ›

Although in its polymeric form, PTFE is considered to be non-toxic and physiologically inert, with the rise in temperature greater than 260 °C, and PTFE resin produces polymer fumes into the working environment. With further increase in temperature to 350 °C, the fumes can cause polymer fume fever in exposed workers.

Is PTFE a hard plastic? ›

PTFE (polytetrefluoroethylene) is a soft, low friction fluoropolymer with outstanding chemical resistance and weathering resistance. PTFE is stable at temperatures up to 500oF and it is often used in high temperature environments. PTFE also has excellent electrical insulating properties.

What are the advantages and disadvantages of PTFE? ›

PTFE Advantages and Disadvantages

Virgin PTFE is white and has the advantages of a very high temperature rating, extremely high lubricity, and being inert to most caustic fluids. A disadvantage is that it's also very soft.

Is PTFE the same as silicone? ›

Silicone or PTFE products are suitable for plastic-to-plastic lubrication, but the silicone will form a thicker, wetter layer that may collect dust and dirt. PTFE will have a thinner, yet harder layer that will not attract dust or absorb grime.

Is all PTFE FDA approved? ›

Features and Benefits of PTFE

Virgin grade PTFE is FDA approved and as a result can be used in high temperature areas in the food processing and service industry as insulators and bearings. The low coefficient of friction makes PTFE an excellent choice for bearing, bushing and other wear applications.

Is PTFE toxic to skin? ›

DAMAGING TO THE SKIN

Teflon (PTFE) attracts damaging free radicals to the skin and causes inflammation. Chronic inflammation can slow the skin's ability to heal itself, speeding the formation of wrinkles and exacerbating other skin conditions like acne and acne scarring.

Is PTFE man made? ›

PTFE is a synthetic, semi-crystalline polymer made up of a carbon backbone surrounded by fluorine atoms. It is produced in a free-radical addition polymerisation reaction between tetrafluoroethylene (TFE) monomers.

Is PTFE cancerous? ›

Over the years, concerns have been raised about how PTFE may affect human health. Specifically: Does PTFE cause cancer? The short answer, according to the experts, is no.

Is PTFE banned in USA? ›

Is Teflon Banned? Teflon and PTFE coatings for food applications are not banned in the United States. However, by 2014, manufacturers worked in conjunction with EPA guidance to voluntarily phase out PTFE created with long chain PFAS such as PFOA and PFOS.

What is the safest cookware to cook with? ›

The safest cookware materials are cast iron, stainless steel, 100% non toxic ceramic, glass, and enamel-coated cast iron (cast iron with a glass coating). These nonstick and non-toxic cookware are not only clean and eco-friendly but also completely safe for our health.

What are the types of PTFE? ›

Here Are 6 Common Types of Teflon Coating
  • Teflon PTFE. Polytetrafluoroethylene or PTFE is the most widely used Teflon coating. ...
  • Teflon FEP. Fluorinated Ethylene Propylene Copolymer or FEP is a completely non-porous film. ...
  • Teflon PFA. ...
  • Tetzel ETFE. ...
  • Teflon One Coat. ...
  • Teflon Dry Lubricant.
Feb 13, 2017

Who makes PTFE? ›

The polymer is synthetic and was created by E. I. du Pont de Nemours and Company (DuPont) in the 1930s. The company's chemical-producing successor, the Chemours Company, remains the largest PTFE manufacturer in the United States, generating more than one-third of industry revenue each year.

Can PTFE be absorbed through skin? ›

The CDC reports that yes, PFAS can get into your body through your skin.

When should you throw away non stick pans? ›

Nonstick Pans Do Not Last Forever

A good rule of thumb is to replace them approximately every five years. Look at your pans frequently. When they start to appear warped, discolored or scratched, be sure to stop using them.

How long does PTFE take to break down? ›

It has been estimated that the particles in Teflon will take about 4.4 million years to break down.

Is PTFE heat resistant? ›

With chemical inertness and temperature resistance ranging from -200 to 260 °C (-328 to 500 °F), Teflon™ fluoropolymers like polytetrafluoroethylene (PTFE) offer nearly unmatched versatility across applications.

Is PTFE free Safe? ›

Modern nonstick cookware is generally considered safe. The American Cancer Society states that there are no proven risks to humans from new PFOA-free nonstick cookware ( 24 ).

Is PTFE harmful to health? ›

Remember that PTFE is an inert substance. It can't harm you.

Is PTFE coating harmful? ›

At normal cooking temperatures, PTFE-coated cookware releases various gases and chemicals that present mild to severe toxicity.

Is PTFE safe to eat? ›

The knock on Teflon is that it's unsafe if consumed or absorbed into the body and can increase the chances of cancer and other diseases. While studies have shown some connections (more on that below), Teflon still exists and is used to make cookware, but the safety concerns around Teflon are mostly a thing of the past.

Is PTFE FDA approved? ›

Features and Benefits of PTFE

Virgin grade PTFE is FDA approved and as a result can be used in high temperature areas in the food processing and service industry as insulators and bearings. The low coefficient of friction makes PTFE an excellent choice for bearing, bushing and other wear applications.

Are non stick pans cancerous? ›

There are concerns that chemicals once used in the manufacturing process of Teflon could potentially increase cancer risk. Those chemicals have not been used in Teflon products since 2013. Today's Teflon is considered to be safe cookware. There's no evidence that it increases the risk of developing cancer.

What is the safest cookware for your health? ›

The safest cookware materials are cast iron, stainless steel, 100% non toxic ceramic, glass, and enamel-coated cast iron (cast iron with a glass coating). These nonstick and non-toxic cookware are not only clean and eco-friendly but also completely safe for our health.

What are the disadvantages of PTFE? ›

Depending on the application, the following disadvantages can rule out the selection of PTFE:
  • Price – it is not a low-cost polymer.
  • Production sizes – it is not easy to mass produce.
  • It cannot be cemented.
  • It can change shape under pressure.
  • It is unweldable.
Jan 11, 2019

Can PTFE be used in medical devices? ›

Polytetrafluoroethylene (PTFE) is a ubiquitous material used for implants and medical devices in general because of its high biocompatibility and inertness: blood vessel, heart, table jawbone, nose, eyes, or abdominal wall can benefit from its properties in case of disease or injury.

At what temperature does PTFE become toxic? ›

When PTFE is heated to over 280℃ (536℉), it releases toxic particles and acidic gases which are toxic when inhaled. These gases are colorless and odorless, so owners are often unaware their bird has been exposed.

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