Teflon

Here in this slide, all the necessary description of Teflon is preset.

1. Teflon Prepared by: Muhammad arslan Tahir Registration No: 2018-mm-14

2. OUTLINE What is Teflon? History of Teflon Production Process Properties Filter performance comparison Processing of Teflon Roadmap to make Teflon Gaskets Advantages of Teflon Main advantages of Teflon Coatings Teflon Wires Effective aspects of Teflon wires Various uses of Teflon wires Carbon filled PTEF Other applications Safety related issues Eco-toxicity

3. WHAT Is Teflon? Polytetrafluoroethylene  ( PTFE ) is a synthetic  fluoropolymer  of  tetrafluoroethylene  that has numerous applications. The well-known brand name of PTFE-based formulas is  Teflon  by  Chemours .  Chemours was a  spin-off  from  DuPont , which originally discovered the compound in 1938.Another popular brand name of PTFE is Syncolon by Synco Chemical Corporation. Chemical Formula: ( C 2 F 4 ) n

4. HISTORY OF TEFLON PTFE was accidentally discovered in 1938 by  Roy J. Plunkett  while he was working in New Jersey for  DuPont . As Plunkett attempted to make a new  chlorofluorocarbon  refrigerant, the  tetrafluoroethylene  gas in its pressure bottle stopped flowing before the bottle's weight had dropped to the point signaling "empty." Since Plunkett was measuring the amount of gas used by weighing the bottle, he became curious as to the source of the weight, and finally resorted to sawing the bottle apart. He found the bottle's interior coated with a waxy white material that was oddly slippery. Analysis showed that it was polymerized perfluoroethylene , with the iron from the inside of the container having acted as a catalyst at high pressure .  Kinetic Chemicals patented the new fluorinated plastic (analogous to the already known  polyethylene ) in 1941 ,  and registered the Teflon trademark in 1945.

5. PRODUCTION PROCESS: PTFE is produced by free-radical polymerization of tetrafluoroethylene. The net equation is n F2C=CF2 → −(F2C−CF2)n− Because tetrafluoroethylene can explosively decompose to tetrafluoromethane and carbon, special apparatus is required for the polymerization to prevent hot spots that might initiate this dangerous side reaction. The process is typically initiated with persulfate, which homolyzes to generate sulfate radicals: [ O3SO−OSO3]2− ⇌ 2 SO4•− The resulting polymer is terminated with sulfate ester groups, which can be hydrolyzed to give OH end-groups . Because PTFE is poorly soluble in almost all solvents, the polymerization is conducted as an emulsion in water. This process gives a suspension of polymer particles. Alternatively, the polymerization is conducted using a surfactant such as PFOS

6. Properties: PTFE is a  thermoplastic   polymer , which is a white solid at room temperature, with a density of about 2200 kg/m 3 . According to research, its melting point is 600 K (327 °C; 620 °F ).  It maintains high strength, toughness and self-lubrication at low temperatures down to 5 K (−268.15 °C; −450.67 °F), and good flexibility at temperatures above 194 K (−79 °C; −110 °F ).  PTFE gains its properties from the aggregate effect of  carbon-fluorine bonds , as do all fluorocarbons. The only chemicals known to affect these carbon-fluorine bonds are highly reactive metals like the  alkali metals , and at higher temperatures also such metals as aluminum and magnesium, and fluorinating agents such as  xenon difluoride  and  cobalt(III) fluoride .  At temperatures above 650–700 °C (1,200–1,290 °F) PTFE undergoes de-polymerization.

7. Filter PERFORMANCE comparison:

8. Processing of Teflon:

9. Roadmap to make Teflon gasket:

10. Advantages of Teflon: 1- Low friction – this means that moving parts that are coated in PTFE will slide with ease, causing less heat, less wear & tear & reducing fire risk. PTFE’s coefficient of friction is the third-lowest of any known solid material 2- Self-cleaning – as PTFE is a non-stick material, dirt won’t stick to it. 3- Effective at a wide range of temperatures – PTFE can handle extremes of temperature that are suitable for many applications. It is effective at continuous surface temperatures up to 260 degrees centigrade and much higher temperatures can be sustained over shorter periods 4- Long-term weather-ability – PTFE is an extremely durable material. For example, it is not affected by ultraviolet and is resistant to oxidation, discoloration, and embrittlement 5- Non-flammability – PTFE offers extraordinary resistance to high temperature and flames because it has a very high melting point and auto-ignition temperature 6- Chemical resistance to corrosive reagents – this means that most chemicals don’t affect it & so it’s the go-to choice for most industries. It’s often used as a gasket where aggressive chemicals are used 7- Great electrical properties – PTFE offers high electrical resistance and dielectric strength

11. 1- It is non-stick 2- It is heat-resistant and cold-resistant 3- It is chemical-resistant 4- It has great electrical properties 5- A wide range of products can be coated in Teflon™ 6- It has an excellent service life, retaining its properties over a long period of time 7- It has a low refractive index, meaning that the product’s visual appearance won’t change after light exposure 8- It doesn’t biodegrade meaning it lasts 9- It is completely resistant to water, making it a great barrier to water & resistant in all ranges of humidity 10- It’s relatively inert: Teflon™ is inert to all solvents and chemicals agents except molten alkali metals and hot fluorine gas Main advantages of Teflon coating services:

12. When it comes to wires, the universe of wires is not constrained to few conventional wires, for example, copper wires etc. The progressive change took them facilitate which give solid variations like Silver Plated Copper Electrical Wire, PTFE Insulated Silver Plated Copper Wire, Silver Coated Copper Wire, and so on. Teflon wires  are additionally a noteworthy piece of the universe of wires that have been viewed as significant for its charming properties. It has noteworthy resistance properties of the chemicals, temperature, dampness, and power which make it simple to enter the opposition without significantly more noteworthy exertion. The perfect material is considered in influencing the wires for its unwavering quality and strength to notwithstanding for the most strenuous applications. Teflon wires:

13. 1- This kind of wires have high dielectric strength 2- These are extremely high operating temperatures. 3- Contains low dissipation factor and also unchanged by susceptibility to humidity, liquid, and moisture Along with these, other features are as following: These Insulated wires are suitable for a wide frequency range Silver plated conductors or your choice of conductor Provides resistance to UV radiation, stress, mold , and chemicals PTFE insulated wires are not subject to creeping or deformity over time Effective aspects of Teflon wires:

14. There are numerous qualities such as electrical resistances, temperature, moisture and chemical that make it an excellent material whenever tools,  products , and components require being reliable in even the most demanding applications. In Medical Field: PTFE covered wires give perfect scope and assurance when medical gadgets require a smooth coating that is smooth, thin, artificially idle, exact and equipped for withstanding a wide assortment of conditions. It’s non-chipping complete settles on it a covering of decision when complete quality is foremost for the two feel and administrative details. At PWI, our forte is protecting the sort of miniaturized scale PTFE covered wire that is habitually utilized as a part of the therapeutic instrumentation, inserts, and different gadgets.   VARIOUS USES OF TEFLON WIRES:

15. Carbon Filled  PTFE  was developed to provide a PTFE based material with improved mechanical strength. PTFE on its own has excellent frictional properties, elasticity and wear resistance but relatively poor mechanical strength and tends to fail in high PV applications . Carbon Filled PTEF Properties: Carbon in itself is a brittle material with poor wear properties and mechanical strength. However with the two combined in Carbon Filled PTFE formulations, the resultant material has excellent mechanical and wear properties, retains the excellent frictional properties and is an excellent choice for seals and rings in dynamic and high pressure applications. Carbon filled PTFE also provides good thermal conductivity, low permeability and is also electrically conductive making it a good choice for anti-static applications. CARBON FILLED PTEF:

16. 1- It is often found in ski bindings as a non-mechanical AFD (anti-friction device) 2- It can be stretched to contain small pores of varying sizes and is then placed between fabric layers to make a waterproof, breathable fabric in outdoor apparel . 3- It is used widely as a fabric protector to repel stains on formal school-wear, like uniform blazers . 4- It is frequently used as a lubricant to prevent captive insects and other arthropods from escaping. 5- It is used as a film interface patch for sports and medical applications, featuring a pressure-sensitive adhesive backing, which is installed in strategic high friction areas of footwear, insoles,  ankle-foot orthosis , and other medical devices to prevent and relieve friction-induced blisters, calluses and foot ulceration. Other Application of Teflon are as:

17. 6- Expanded PTFE membranes have been used in trials to assist  trabeculectomy  surgery to treat glaucoma . 7- Powdered PTFE is used in  pyrotechnic compositions  as an  oxidizer  with powdered metals such as  aluminum  and  magnesium . Upon ignition, these mixtures form carbonaceous  soot  and the corresponding metal  fluoride , and release large amounts of heat. They are used in  infrared decoy flares  and as  igniters  for  solid-fuel rocket   propellants .   Aluminum and PTFE is also used in some  thermobaric  fuel compositions. 8- Powdered PTFE is used in a suspension with a low-viscosity, a zeotropic mixture of siloxane ethers to create a lubricant for use in twisty puzzles . 9- In optical  radiometry , sheets of PTFE are used as measuring heads in spectroradiometers and broadband radiometers (e.g.,  illuminance  meters and  UV   radiometers ) due to PTFE's capability to diffuse a transmitting light nearly perfectly. Moreover, optical properties of PTFE stay constant over a wide range of wavelengths, from UV down to near  infrared . In this region, the ratio of its regular transmittance to diffuse transmittance is negligibly small, so light transmitted through a  diffuser  (PTFE sheet) radiates like  Lambert's cosine law . Thus PTFE enables sinusoidal angular response for a detector measuring the power of optical radiation at a surface, e.g. in solar  irradiance  measurements.

18. 10- Certain types of bullets are coated with PTFE to reduce wear on the rifling of firearms that uncoated projectiles would cause. PTFE itself does not give a projectile an armor-piercing property . 11- Its high corrosion resistance makes PTFE useful in laboratory environments, where it is used for lining containers, as a coating for magnetic stirrers, and as tubing for highly corrosive chemicals such as  hydrofluoric acid , which will dissolve glass containers. It is used in containers for storing  fluoroantimonic acid , a  super acid . 12- PTFE tubes are used in gas-gas heat exchangers in gas cleaning of waste incinerators. Unit power capacity is typically several megawatts. 13- PTFE is widely used as a  thread seal tape  in plumbing applications, largely replacing paste thread dope. 14- PTFE membrane filters are among the most efficient industrial air filters. PTFE-coated filters are often used in  dust collection systems  to collect  particulate matter  from air streams in applications involving high temperatures and high particulate loads such as coal-fired power plants, cement production and steel foundries . 15- PTFE grafts can be used to bypass  stenotic   arteries  in peripheral vascular disease if a suitable autologous  vein  graft is not available. 16- Many bicycle lubricants and greases contain PTFE and are used on  chains  and other moving parts subjected to frictional forces (such as  hub bearings ). 17- EPTFE is used for some types of  dental floss .

19. SAFETY RELATED ISSUES Pyrolysis  of PTFE is detectable at 200 °C (392 °F), and it evolves several  fluorocarbon  gases and a  sublimate . An animal study conducted in 1955 concluded that it is unlikely that these products would be generated in amounts significant to health at temperatures below 250 °C (482 °F ).Products like non-stick coated cookware have had their  PFOA  removed since 2013  and prior to this products containing  PFOA  weren't found to be major sources of exposure . While PTFE is stable and nontoxic at lower temperatures, it begins to deteriorate after the temperature of cookware reaches about 260 °C (500 °F), and decomposes above 350 °C (662 °F ).  The degradation by-products can be lethal to  birds ,  and can cause  flu-like symptoms  in humans—see  polymer fume fever . Meat is usually fried between 204 and 232 °C (399 and 450 °F), and most oils start to  smoke  before a temperature of 260 °C (500 °F) is reached, but there are at least two cooking oils (refined  safflower oil  at 265 °C (509 °F) and  avocado oil  at 271 °C (520 °F)) that have a higher  smoke point . However these cases of polymer fume fever were mostly present in people who had cooked at 390 °C (734 °F) for ⪰4 hours .

20. ECOTOXICITY Sodium trifluoroacetate  and the similar compound chlorodifluoroacetate can both be generated when PTFE undergoes thermolysis, as well as producing longer chain polyfluoro- and/or polychlorofluoro- (C3-C14) carboxylic acids which may be equally persistent. Some of these products have recently been linked with possible adverse health and environmental impacts and are being phased out of the US market. [61] Perfluorooctanoic acid (PFOA) is sometimes used in the process of making PTFE/Teflon, although it is burned off during this process and is not usually present in significant quantities in the resultant PTFE

21. SIMILAR POLYMERS The Teflon trade name is also used for other polymers with similar compositions: Perfluoroalkoxy alkane  (PFA) Fluorinated ethylene propylene  (FEP) These retain the useful PTFE properties of low friction and non reactivity , but are also more easily formable. For example, FEP is softer than PTFE and melts at 533 K (260 °C; 500 °F); it is also highly transparent and resistant to sunlight .

22. 1- Up until 2015, Teflon was made using a chemical called  perfluorooctonoic acid , or PFOA. It is a suspected carcinogen, hormone disruptor, and reproductive toxin. It is also highly persistent, which means once it enters the environment it does not leave (think of what this means for our drinking water, seafood, and farmland soils). 2- While it is thought that most of the  carcinogenic chemicals  are eliminated during manufacture, small amounts may remain. And  when Teflon is overheated , these chemicals can enter the food being cooked. It is a known toxin to birds, which is why Teflon products (including self-cleaning ovens) include a warning to  remove any birds  from the room when being heated. Exposure to Teflon that has been overheated can result in flu-like symptoms in humans (metal or  polymer fume fever ). 3- Because of the concerns to human health and the environment around PFOA, many manufacturers are phasing it out, including the  Teflon  brand. However, there is little to no information about what the alternative process or chemicals are. The good news is, there are alternatives. Dangers of Teflon: