American painter, art instructor, and beloved television host Bob Ross once said, “We don’t make mistakes. We just have happy accidents.” Ross understood that even when things do not go as planned, something unexpectedly wonderful can result.
Scientific discovery is rampant with examples of happy accidents that changed the world. As it turns out, many of society’s most famous inventions were merely errors made by scientists pursuing unrelated goals:
Like those great discoveries, polytetrafluoroethylene, or PTFE, was created by a happy accident.
PTFE was discovered by chemist Dr. Roy Plunkett while attempting to develop a coolant gas. He was experimenting with tetrafluoroethylene (TFE) for synthesis of useful refrigerants. On the morning of April 6, 1938, the TFE gas inside had polymerized into a waxy white powder, polytetrafluoroethylene (PTFE) resin.
Plunkett had analyzed the white powder, which was conclusively proven to be PTFE. The slippery PTFE could not be dissolved in any solvent, acid, or base, and upon melting formed a stiff, clear gel without flow. The accidental discovery of PTFE revolutionized the plastics industry during World War II and led to various applications not otherwise possible.
In the over 80 years since its discovery, PTFE (often referred to as Teflon®1) has revolutionized the production of a multitude of essential goods and enriched the capabilities of many vital industries. With a robust characteristic profile, a wide breadth of applications, and its unique mechanical properties, it’s no surprise that PTFE is regarded as a wonder material.
The unique properties of PTFE have led to a wide variety of applications, including food preparation, electronics, aviation, medical implants, and so much more. Before we look at the various industries, let’s look at some of the characteristics of this wonder material:
Characteristics like chemical inertness, heat resistance, excellent electrical insulation, and a low coefficient of friction enable PTFE to be used in a wide variety of applications, including seals, gaskets, compressor valves and pump parts, wire insulation, insulated transformers, printed circuit boards, textiles, and surface coatings.
This robust profile makes PTFE a versatile material for an incredible number of products, shapes, and design applications. Some of PTFE’s basic near net shapes include discs, rods, tubes, blocks, sheets, balls, plates, and molded blanks (also known as billets).
PTFE can also be custom designed into very intricate parts and components subject to some of the highest quality standards and specifications. PTFE’s diversity of application makes it perfect for so many industries that drive our world.
You may have heard people ask the question: If nothing sticks to Teflon, how does Teflon stick to pots and pans? The answer is Teflon’s slick surface is due to the fluorine that surrounds its molecules.
Almost all other materials are repellent to these fluorine atoms, preventing them from sticking to Teflon. However, by chemically modifying one side of the Teflon, chemists can break away many of the fluorine atoms on the surface and mitigate Teflon’s natural anti-adhesion characteristics.
The changes to one side of the Teflon are done with a reducing agent that breaks the strong bonds between the fluorine and the carbon, allowing the fluorine to bond together. This leaves the carbon free. The free carbon, which forms into unsaturated hydrocarbons, is sticky enough to get the Teflon sheet to stick to a pan.
PTFE is most commonly known for its nonstick characteristics and its prevalence as a coating in food preparation products like pots, pans, and more. Outside of the kitchen, PTFE plays a significant role in a host of industries. Let’s take a look at some of those industries and the key benefits at work:
At this point, it might be easy to think of PTFE as the picture-perfect thermoplastic material. Like all materials, PTFE has its own share of limitations, including sensitivity to creep and abrasion, low radiation resistance, and difficulties of joining.
Depending on the application and environment, some of PTFE’s limitations can be improved with the addition of fillers or additives. Let’s take a look at some of the more common fillers and additives as well as some of their benefits:
If not for an accident on the morning of April 6, 1938, the world as we know it would likely be a very different place. We have only scratched the surface on the many applications for PTFE. Scientists and chemists are constantly experimenting with PTFE and discovering new and safe applications for this amazingly versatile material.
Tough, flexible, waterproof – the list goes on. So do the potential opportunities for PTFE to positively impact the world. Every day, scientists uncover a new way PTFE can improve a product or resource – often by happy accident – and we anticipate many more discoveries in the future.
PTFE is a thermoplastic that cannot be handled using typical polymer processing procedures due to its high viscosity. PTFE is processed by cold shaping followed by heat treatment (also known as sintering), which causes the polymer particles to fuse together to produce a solid molding.
Some of the production techniques/manufacturing processes for granular and fine powder polymers are:
Some of the production techniques/manufacturing processes for melt processable fluoropolymers are:
To learn more about the production capabilities for your next project, for custom-engineered components or near net shapes, contact us today.
1The Teflon® trademark was coined by DuPont and registered in 1945; the first products were sold commercially under the trademark beginning in 1946.