9002-84-0 Usage
Description
Poly(tetrafluoroethylene), commercially known as PTFE, is a strong, tough, waxy, and nonflammable synthetic resin with a carbon backbone chain and a structure formula of [CF2-CF2]n. It is produced through the free-radical polymerization of tetrafluoroethylene and is known for its slippery surface, high melting point, and extreme chemical inertness. PTFE exhibits high thermal stability, excellent chemical resistance, low dielectric constant, and low surface energy, making it a versatile material for various applications.
Uses
Used in Cookware Industry:
Poly(tetrafluoroethylene) is used as a non-stick coating for cookware due to its slippery surface and high thermal resistance.
Used in Inks, Plastics, Coatings, and Lubricants Industry:
Poly(tetrafluoroethylene) is used as an ingredient in inks, plastics, coatings, and lubricants for its chemical inertness, low friction coefficient, and resistance to chemical attack.
Used in Mechanical Parts Industry:
Poly(tetrafluoroethylene) is used as gaskets, seals, bearings, gears, and other machine parts due to its low friction, high thermal stability, and resistance to chemical attack.
Used in Linings, Insulation, Membranes, and Adhesives Industry:
Poly(tetrafluoroethylene) is used as liners, insulation, membranes, and adhesives for its chemical inertness, high thermal resistance, and low surface energy.
Used in Plumbing Work:
Teflon tape, made of Poly(tetrafluoroethylene), is commonly used in plumbing work for its non-stick properties and resistance to chemical attack.
Used in Rainproof Garments:
Poly(tetrafluoroethylene) is used to produce rainproof garments due to its hydrophobic nature and chemical inertness.
Used in Electronic Equipment and Computer Wire Industry:
Poly(tetrafluoroethylene) is used for hookup and hookup-type wire in electronic equipment, computer wire, electrical tape, electrical components, and spaghetti tubing due to its excellent dielectric properties and resistance to high temperatures.
Used in Chemical Laboratory and Process Work:
Poly(tetrafluoroethylene) is used as tubing and sheets for chemical laboratory and process work, for lining reaction vessels, and for gaskets and pump packings due to its chemical resistance and high thermal stability.
Used in Cosmetic Preparations:
Poly(tetrafluoroethylene) is used as a bulking agent in cosmetic preparations to improve the formulation's feel and spreadability, and it may also have some waterproofing potential.
Used in Industrial Applications:
Poly(tetrafluoroethylene) is used in industrial applications under extreme conditions of heat and chemical activity, such as bearings, valve seats, packings, gaskets, coatings, and tubing, due to its insolubility, resistance to heat and chemical attack, and low coefficient of friction.
Used in Plastic Modification:
Polytetrafluoroethylene powder is used for plastic modification, with average particle sizes of 3-5 and 10-20 micrometers, for its unique properties, including no self-coagulation, no electrostatic effect, good intermiscibility, low molecular weight, good dispersion, high self-lubrication, and low friction coefficient.
Preparation
Poly(tetrafluoroethylene) is prepared from tetrafluoroethylene and consists of repeating units in a predominantly linear chain:
F2C=CF2 --->[-CF2-CF2-]n
Tetrafluoroethylene polymer has the lowest coefficient of friction of any solid. It has remarkable chemical resistance and a very low brittleness temperature (100C). Its dielectric constant and loss factor are low and stable across a broad temperature and frequency range. Its impact strength is high.
Preparation
The preferred commercial method of preparation of polytetrafluoroethylene
(PTFE) is by suspension polymerization. The details of the procedures
employed have not been disclosed but it appears that two main processes are
in use. In the first process, the conventional techniques of suspension polymerization are used to produce a granular product suitable for moulding and
extrusion. The tetrafluoroethylene is polymerized under pressure in stainless
steel autoclaves with a free radical initiator such as ammonium persulphate.
The reaction is rapid and exothermic and requires careful control. The
polymer granules are collected, washed and dried. In the second process,
conditions are adjusted to give a dispersion of polymer of much finer particle
size and lower molecular weight. The product may be stabilized and employed in latex form in such uses as film casting, coating and impregnation of
fibres. Alternatively, the product may be coagulated to give a powder (often
called 'dispersion polymer') used mainly for the extrusion of thin flexible
sections.
References
http://pslc.ws/macrog/ptfe.htm
https://global.britannica.com/science/polytetrafluoroethylene
https://en.wikipedia.org/wiki/Polytetrafluoroethylene#Other
History
The polymerized form of TFE was discovered accidentally by researchers at DuPont in 1938. During the mid-1930s, DuPont was investigating the development of new chlorofl uorocarbons (CFCs) for use as refrigerants. DuPont joined with General Motors to form a company called Kinetic Chemicals to combine their efforts in this area. Plunkett examined the properties of the substance. He discovered that the substance was inert to other chemicals, had a high melting point, and was very slippery. Plunkett also worked on duplicating the conditions necessary to produce it from TFE. He applied for a patent for polytetrafl uoroethylene polymers in 1939, which was granted in 1941 (U.S. Patent 2230654). He assigned the patent to Kinetic Chemicals. DuPont registered the term Tefl on in 1945 and introduced Tefl on products the next year.Teflon is best known for its use in cookware, but its use in this area followed original industrial
applications in gaskets, sealers, tape, and electrical insulation. Th ese applications were a
direct result of the use of PTFE for military purposes during World War II.
Production Methods
Polytetrafluoroethylene is generally made from tetrafluoroethylene
gas by free-radical polymerization under pressure
with oxygen, peroxides, or peroxydisulfates. The “granular
resins” have medium-size particles that range from 30 to
600 mm. Colloidal aqueous dispersions, made by a different
process, are concentrated to about 60% by weight of the
polymer and have particles that average about 0.2 mm.
Coagulated dispersions with agglomerates that average
450mm are also available .
The use of PTFE as a release agent in coatings and certain
other food contact applications is permitted under FDA
regulations .
Hazard
Evolves toxic fumes on heating. Question-
able carcinogen.
Health Hazard
Fumes of heated polytetrafluoroethylene (PTFE) cause polymer fume fever,
an influenza-like syndrome.
Safety Profile
The finished polymerized compound is inert under ordinary condtions. There have been reports of “polymer fume fever” in humansexposed to pyrolysis products, whch also are irritants. Smohng should be prohibited in areas where ths material is being fabricated or, in general, where there may be dust from it. Exposure to pyrolysis or decomposition products appears to be the chief health-related problem. Questionable carcinogen with experimental tumorigenic data by implant. Incompatible with fluorine, sodmm potassium alloy. Under the proper conditions it undergoes hazardous reactions with boron, magnesium, or titanium. When heated to above 750°F it decomposes to yield highly toxic fumes of F-.
Carcinogenicity
Animal studies have not demonstrated
that this polymer is carcinogenic. No data are
available in humans. The polymer is not classifiable as to
its human carcinogenicity. However, the EPA found that
perfluorooctanoic acid (PFOA), a chemical used to produce
PTEE is a “likely carcinogen.
Environmental Fate
PTFE is the most stable of all TFE polymers and under physiological
conditions does not release any components (IARC
Monograph 74, 1999). PTFE is very inert chemically; only alkali
metals and fluorine under pressure attack PTFE (Hazardous
Substances Data Bank (HSDB)). There are no known ecotoxicological
effects for PTFE (DuPont MSDS, 2011).
Toxicity evaluation
There is no apparent mechanism of toxicity for orally administered
PTFE as no toxicologically significant effects were
observed following oral administration to rats for up to
90 days. The lack of toxicity is most likely due to the following:
(1) gastrointestinal absorption of PTFE is negligible given its
extremely high molecular weight (1 000 000–10 000 000 for
PTFE fine powder); (2) PTFE is chemically inert under physiologic
conditions; and (3) PTFE is not metabolized (Donovan
et al., 1990; Kim, 1996; Veber et al., 2002). The mechanism
of action of subcutaneously injected PTFE in mice is attributed
to localized inflammation consistent with a foreignbody
response; similar effects were seen following subareolar
injection in rabbits and dogs, and periurethral injections
in dogs.
When PTFE is heated or exposed to temperatures ≥200°C,
it will decompose and release toxic vapors that cause polymerfume
fever in humans.
Check Digit Verification of cas no
The CAS Registry Mumber 9002-84-0 includes 7 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 4 digits, 9,0,0 and 2 respectively; the second part has 2 digits, 8 and 4 respectively.
Calculate Digit Verification of CAS Registry Number 9002-84:
(6*9)+(5*0)+(4*0)+(3*2)+(2*8)+(1*4)=80
80 % 10 = 0
So 9002-84-0 is a valid CAS Registry Number.
