Polytetrafluoroethylene (PTFE for short),It is also called Teflon,[5]Commonly known as "plastic king", it is made by polymerization of tetrafluoroethylene as monomerPolymer, the chemical formula is (CtwoFfour）n. It has excellent heat resistance and cold resistance, and can be used for a long time at - 180~260 º C.This material has the characteristics of acid resistance, alkali resistance and resistance to various organic solvents, and is almost insoluble in all solvents.At the same time, polytetrafluoroethylene has the characteristics of high temperature resistance, and its friction coefficient is extremely low, so it can be used as a lubricant and also become an ideal coating for easy cleaning the inner layer of water pipes.
On October 27, 2017, the list of carcinogens published by the International Agency for Research on Cancer of the World Health Organization (WHO) was preliminarily sorted out for reference, and polytetrafluoroethylene was included in the list of category 3 carcinogens.
Chinese name
teflon
Foreign name
Polytetrafluoroethylene（PTFE）
Alias
Teflon[5]、Plastic King
chemical formula
(CtwoFfour)n
CAS login number
9002-84-0
EINECS login number
204-126-9
Melting point
321 to 344 ℃
Boiling point
400 ℃
Water solubility
Insoluble in any solvent
Appearance
White solid
Monomer molecular weight
one hundred point zero one five
Heat capacity
1.50J/g°C[1]
Modulus of elasticity
0.390 - 0.750 GPa[1]
Hardness
fifty-eight[1]
resistivity
tenfourteen- 10nineteenΩ.cm[1]
Dielectric constant
2.-0-2.1[1]
thermal conductivity
0.167 - 0.300 W/m.K[1]
Refractive index
1.37（20℃）[1]
Storage conditions
Normal temperature, airtight, dark, ventilated and dry place
1. Stable under normal temperature and pressure, avoiding wet, hot and high temperature.No real melting point, slowly decomposes above 450 ℃ and directly turns into gas.At 327 ℃, the mechanical strength suddenly disappears.Insoluble in any solvent.In addition to reacting with molten alkali metal, it is not corroded by any substance, even inhydrofluoric acid、Aqua regiaOr fuming sulfuric acid, sodium hydroxide, and no change.
2. White, odorless, tasteless, non-toxic powder, commonly known as the "King of Plastics".It has excellent chemical stability, corrosion resistance, sealing, high lubrication, non viscosity, electrical insulation and good anti-aging endurance.High temperature resistance, operating temperature up to 250 ℃.It is resistant to low temperature and has good mechanical toughness at low temperature. Even if the temperature drops to - 196 ℃, it can maintain 5% elongation.Corrosion resistant, inert to most chemicals and solvents, resistant to strong acids and alkalis, water and various organic solvents.Good weather resistance, with the best aging life in plastics.High lubrication is the lowest friction coefficient among solid materials.No adhesion, which is the smallest surface tension among solid materials, and does not adhere to any substance.It is non-toxic and physiologically inert, and has no adverse reaction after long-term implantation as an artificial blood vessel and organ.
Solubility
Insoluble in any solvent
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1. Character: There are three types: granular, powdery and dispersed liquid. It is transparent when it is neutral, and becomes grayish white with increased thickness
The preparation of tetrafluoroethylene monomerTrichloromethaneAs raw material, useAnhydrous hydrofluoric acidFluoride trichloromethane at a reaction temperature above 65 ℃, use antimony pentachloride as catalyst, and finally use hot cracking method to produce tetrafluoroethylene.Tetrafluoroethylene can also be prepared by the reaction of zinc with tetrafluorodichloroethane at high temperature.The preparation of polytetrafluoroethylene is in an enamel or stainless steel polymerizer. The polytetrafluoroethylene is prepared by radical polymerization of tetrafluoroethylene with water as the medium, potassium persulfate as the initiator, ammonium perfluorocarboxylate as the dispersant, fluorocarbon compounds as the stabilizer, and tetrafluoroethylene[4]。At the same time, different polytetrafluoroethylene materials have different preparation processes, such as:
1. Granular PTFE material is produced by suspension polymerization with little or no dispersant in aqueous medium.Granular polytetrafluoroethylene material is mainly used in compression, isostatic pressing and plunger extrusion processing methods.
2. The water-based water-based PTFE dispersion uses the same water-based polymerization, and more dispersants are used and stirred.Water based dispersions are mainly used in coating and film casting methods.
3. Fine powder Fine powder PTFE is a small white particle made by controlled emulsion polymerization.Fine PTFE powder can be processed into thin sheets by paste extrusion or additives to improve wear resistance.
application area
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1. Corrosion protection: PTFE materials have been widely used in petroleum, textile and other industries due to their outstanding corrosion resistance.The representative ones include exhaust pipes, steam pipes, high, medium and low pressure pipes, valves, etc.Especially in the harsh environmental conditions such as low temperature and anti sticking, where conventional materials cannot be used, PTFE has more advantages.
2. Electronic and electrical aspects: polytetrafluoroethylene has a relatively small dielectric constant, so it can be used to prepare enameled wires for use in micro motors.In addition, the fluoroplastic film has certain selective permeability to various gases, so this feature can be used to prepare oxygen sensors.Nowadays, various forms of PTFE materials play an important role in the field of electronic and electrical insulation.PTFE glass lacquered cloth and glass cloth are used to make insulating materials with high temperature and high frequency, which can be used in satellite communication, computer, etc;PTFE film is used to make capacitors as insulation layer, gasket, cable, etc. between instruments;PTFE thin-walled pipes with different diameters are used for outgoing line sleeves, heat shrinkable pipes, spiral pipes, insulated water pipes of generators, etc.
3. In medical treatment: polytetrafluoroethylene has excellent biocompatibility. In recent years, many people have carried out in-depth research on it as a biomaterial. In recent years, PTFE membrane has been developed at home and abroad to be used as artificial organs, such as artificial blood vessels, heart valves, etc. For example, in clinical practice, it is used as a prosthetic scaffold material in artificial blood vessels and nasal plastic surgery,Good results have been achieved.
4. In the aspect of architecture: PTFE resin is coated on the superfine glass fiber fabric, which is characterized by light weight, high strength, fire and flame resistance, good self-cleaning, free from ultraviolet radiation, fatigue resistance, distortion resistance, aging resistance, long service life, high light transmittance and little heat absorption.It is precisely because of this cross era invention of membrane materials that membrane structure buildings become modern permanent buildings.
5. Low friction performance In terms of load: because its friction coefficient is relatively low compared with most solid materials, filled PTFE has gradually evolved into an excellent oil-free lubrication material for various parts.It has a wide range of applications, including chemical equipment bearings, piston rings, supporting sliders of steel roof truss and bridge erection swivel.
Calculate chemical data
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1. Drainage parameter calculation reference value (XlogP): 0
2. Number of hydrogen bond donors: 0
3. Number of hydrogen bond receptors: 0
4. Number of rotatable chemical bonds: 0
5. Number of tautomers: none
6. Topological molecular polar surface area 0
7. Number of heavy atoms: 0
8. Surface charge: 0
9. Complexity: 0
10. Number of isotope atoms: 0
11. Determine the number of atomic structure centers: 0
12. Number of uncertain atomic structure centers: 0
13. Determine the number of chemical bond structural centers: 0
14. Number of indeterminate chemical bond structure centers: 0
three billion nine hundred and four million six hundred and ten thousand
Storage and transportation
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Operation precautions
Closed operation, providing good natural ventilation conditions.Operators must be specially trained and strictly abide by the operating procedures.It is recommended that operators wear self-priming filter type dust masks.Keep away from kindling and heat sources, and smoking is strictly prohibited in the workplace.Use explosion-proof ventilation systems and equipment.Avoid dust generation.Avoid contact with oxidants.Load and unload gently during transportation to prevent damage to packaging and containers.Fire fighting equipment and leakage emergency treatment equipment of corresponding types and quantities shall be provided.
Precautions for storage
Store in a cool and ventilated warehouse.Keep away from kindling and heat sources.It shall be stored separately from oxidant and shall not be mixed.Equip with corresponding types and quantities of fire-fighting equipment.The storage area shall be equipped with appropriate materials to contain leakage
Hazard Overview
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Invasion route: no data
Health hazard: The product is basically non-toxic, but the pyrolytic composition, content and toxicity of PTFE often increase with the increase of heating temperature.Inhalation of thermal decomposition products may cause poisoning.Mild poisoning manifested fever and "cold like" symptoms;In severe cases, respiratory irritation symptoms, chemical bronchitis, pneumonia, and even pulmonary edema and myocardial damage occur.Long term low concentration exposure to its pyrolysis products often leads to headache, dizziness, insomnia, nightmares, memory loss, fatigue, low back pain, etc.
Environmental hazard: no data
Flammability hazard: This product is flammable.
First aid measures
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Skin contact: no data
Eye contact: no data
Inhalation: quickly leave the site to a place with fresh air.Keep the respiratory tract unobstructed.If breathing is difficult, give oxygen.If breathing stops, perform artificial respiration immediately.Get medical attention.
Ingestion: no data
toxicology data
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Tumorigenicity: infusion test in rats: TDLo: 80 mg/kg;Mice infusion test: TCLo: 1140 mg/kg.
Ecological data
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This substance may be harmful to the environment, and special attention should be paid to water bodies.
