Views: 3 Author: Site Editor Publish Time: 2023-02-16 Origin: Site
Polytetrafluoroethylene (hereinafter referred to as PTFE), also known as Teflon, is a polymer compound made of tetrafluoroethylene by polymerization, with excellent chemical stability, corrosion resistance, high and low temperature resistance, electrical insulation, surface non-stick, etc., which is less than many other engineering plastics, it solves many problems in the chemical, petroleum, electrical, pharmaceutical and other fields, and therefore has the "king of plastics It has solved many problems in chemical, petroleum, electrical, pharmaceutical and other fields, so it has the name of "King of Plastics". So, how was Teflon (polytetrafluoroethylene) discovered?
In the first 50 years of the 20th century, DuPont was like Google, Tesla and SpaceX nowadays, always with new inventions and creations to set the trend of the times. After the commercialization of Freon, they found a new business opportunity.
Roy Plunkett, a chemist at DuPont's Jackson Laboratory, came to DuPont in 1932 to work on organic fluorine, and in the summer of 1938, Plunkett was working on the preparation of chlorofluorocarbons (CFCs), and although the previous successful commercial CFCs were chlorofluoroalkanes, he became interested in chlorofluoroolefins.
He chose the simplest one, tetrafluoroethylene, which he stored in dry ice cooled cylinders for further study. One day, he opened the cylinder with his assistant, hoping that the tetrafluoroethylene would vaporize through a flow meter into the reactor. But before long, they found that the flow of tetrafluoroethylene had stopped, and the mass of the cylinder showed that there was still quite a bit inside. Plunkett shook the cylinder and found some solids rattling around inside.
He took the valve off and poured some white powder out of the cylinder. Then he used a hacksaw to saw the cylinder open, and found that there was still a considerable amount of white powder inside. In 1945, DuPont registered the trademark of Teflon for PTFE, which was called Teflon in Chinese.
The DuPont trademark has always been synonymous with a product. We need these great innovative companies for our development
Once Teflon was made, it was found to be a really superb material. It is very resistant to cold, even to temperatures as low as -269.3 degrees Celsius. It is simply trivial at the temperature level of dry ice, liquid nitrogen, liquid oxygen, liquid air, and it even stays golden in liquid helium. Its heat resistance is not as excellent as its cold resistance, but it can also withstand temperatures up to 250 degrees.
It is particularly resistant to corrosion, whether it is strong acids and bases, such as sulfuric acid, hydrochloric acid, nitric acid, caustic soda and even aqua regia, or strong oxidizers, such as potassium dichromate, potassium permanganate, can not move it half a hair. It can be said that its chemical stability exceeds that of glass, ceramics, stainless steel, and even gold and platinum. We know that even gold and platinum will dissolve in aqua regia, however, Teflon remains the same when boiled in aqua regia for dozens of hours.
It is also particularly difficult to be wetted, and it does not swell and its weight does not increase when it is immersed in water for a year. So far, no solvent has been found that can make Teflon swell.
French engineer Marc Gregoire, a lover of fishing, was often annoyed by tangled fishing lines. He found that the surface of the Teflon coating was particularly smooth, so he applied the Teflon to his fishing line. Sure enough, if his fishing line got tangled together, it would untangle smoothly with a gentle tug.
In 1954, his wife Colette saw this and had the idea that if Teflon was applied to the surface of the pan, wouldn't that save a lot of worry in the future, no longer having to worry about pancakes getting on the pan. Griguaer listened to his wife's suggestion and immediately put his brain to work, and developed a way to combine Teflon and aluminum, and the world's first "non-stick" pan was born.
Previously, there is a network article mentioning that the surface of the non-stick pan Teflon is highly toxic substances, and calls on everyone to boycott non-stick pans; there are some people propose that the use of non-stick pans to cook some acidic food, will release carcinogenic substances. This is a little ignorant fearless, PTFE is a very stable substance, completely chemically inert, acidic food so little acid from the aqua regia is still far away, how may react with PTFE? As long as you do not let the non-stick pan dry-fire, to more than 250 degrees high temperature, PTFE will not even melt, not to mention decomposition.
Therefore, we still need to understand the chemistry of ah, in order to better life.
Teflon, the king of plastics, is not only used in the kitchen, because it is particularly smooth, in the machinery of various bearings, gears, pulleys can be used to do it. Since there are equipment friction parts should not be oil lubrication, such as in the lubricating grease will be dissolved by the solvent and failure of the occasion or paper, pharmaceutical, food, textile and other industrial areas of the product needs to avoid lubricant staining, which makes the filling PTFE material to become the most ideal material for mechanical equipment parts without oil lubrication (direct load bearing). PTFE has the lowest coefficient of friction of any known solid material, and it performs far better than phenolic resins, nylon, and probably only ultra-high molecular weight polyethylene can match it.
This excellent property of PTFE coating has been used in the coating of many composite materials, even in aircraft in the aviation industry.
High-end composite materials are mostly carbon fiber and glass fiber, both of which are much weaker than PTFE in terms of corrosion resistance, so they are coated with a layer of PTFE to provide a good barrier. This is not only used in the aviation industry, but also in other areas such as construction, such as the world-famous Burj Al Arab in Dubai.
The Burj Al Arab, also known as the "Sailboat Hotel", is the world's first seven-star hotel. Its exterior is made of fiberglass coated with Teflon, a surface film material that is resistant to ultraviolet light, fire, day and night temperatures and sandstorms. At night, they turn into a giant projection screen, indulging luxury to the extreme.
With the continuous development of material application technology, the three major disadvantages of PTFE material: cold flow, difficult to weld, and difficult to melt processability are being gradually overcome, thus making it more promising in a variety of fields such as optics, electronics, medicine, petrochemical oil transfer and impermeability.
In addition, the dielectric properties of PTFE are particularly good, and its dielectric properties are independent of frequency and do not change with temperature, which allows it to be used as a very good insulating material in electrical appliances.