Fluorinated ethylene propylene
Encyclopedia
FEP
Density
Density
The mass density or density of a material is defined as its mass per unit volume. The symbol most often used for density is ρ . In some cases , density is also defined as its weight per unit volume; although, this quantity is more properly called specific weight...

2150 kg/m3
Flexural modulus
Flexural modulus
In mechanics, the flexural modulus is the ratio of stress to strain in flexural deformation, or the tendency for a material to bend. It is determined from the slope of a stress-strain curve produced by a flexural test , and uses units of force per area...

(E)
586 MPa
Pascal (unit)
The pascal is the SI derived unit of pressure, internal pressure, stress, Young's modulus and tensile strength, named after the French mathematician, physicist, inventor, writer, and philosopher Blaise Pascal. It is a measure of force per unit area, defined as one newton per square metre...

Tensile strength
Tensile strength
Ultimate tensile strength , often shortened to tensile strength or ultimate strength, is the maximum stress that a material can withstand while being stretched or pulled before necking, which is when the specimen's cross-section starts to significantly contract...

(t)
23 MPa
Pascal (unit)
The pascal is the SI derived unit of pressure, internal pressure, stress, Young's modulus and tensile strength, named after the French mathematician, physicist, inventor, writer, and philosopher Blaise Pascal. It is a measure of force per unit area, defined as one newton per square metre...

Elongation @ break 325%
Folding endurance Varies
Notch test
Melting point
Melting point
The melting point of a solid is the temperature at which it changes state from solid to liquid. At the melting point the solid and liquid phase exist in equilibrium. The melting point of a substance depends on pressure and is usually specified at standard atmospheric pressure...

260 °C
Maximum operating
temperature 204 °C
Water absorption (ASTM) <0.01 % after 24 hours
Dielectric constant
Dielectric constant
The relative permittivity of a material under given conditions reflects the extent to which it concentrates electrostatic lines of flux. In technical terms, it is the ratio of the amount of electrical energy stored in a material by an applied voltage, relative to that stored in a vacuum...

(Dk)
at 1MHz
Hertz
The hertz is the SI unit of frequency defined as the number of cycles per second of a periodic phenomenon. One of its most common uses is the description of the sine wave, particularly those used in radio and audio applications....

2.1
Dissipation factor
at 1MHz
Hertz
The hertz is the SI unit of frequency defined as the number of cycles per second of a periodic phenomenon. One of its most common uses is the description of the sine wave, particularly those used in radio and audio applications....

0.0007
Arc resistance < 300 seconds
Resistivity
Resistivity
Electrical resistivity is a measure of how strongly a material opposes the flow of electric current. A low resistivity indicates a material that readily allows the movement of electric charge. The SI unit of electrical resistivity is the ohm metre...

at 50% R.H.
Relative humidity
Relative humidity is a term used to describe the amount of water vapor in a mixture of air and water vapor. It is defined as the partial pressure of water vapor in the air-water mixture, given as a percentage of the saturated vapor pressure under those conditions...

> 1016 Ω
Ohm
The ohm is the SI unit of electrical resistance, named after German physicist Georg Simon Ohm.- Definition :The ohm is defined as a resistance between two points of a conductor when a constant potential difference of 1 volt, applied to these points, produces in the conductor a current of 1 ampere,...

m

Fluorinated ethylene propylene or FEP is a copolymer of hexafluoropropylene
Hexafluoropropylene
Hexafluoropropylene is a compound with the formula C3F6. It is a fluorocarbon alkene in which all of the hydrogen atoms in propylene are replaced by fluorine atoms. It is used as a chemical intermediate....

and tetrafluoroethylene
Tetrafluoroethylene
Tetrafluoroethylene is a chemical compound with the formula C2F4. It is the simplest alkene fluorocarbon. This gaseous species is used primarily in the industrial preparation of polymers.-Properties:...

. It differs from the PTFE (polytetrafluoroethylene
Polytetrafluoroethylene
Polytetrafluoroethylene is a synthetic fluoropolymer of tetrafluoroethylene that finds numerous applications. PTFE is most well known by the DuPont brand name Teflon....

) resins in that it is melt-processible using conventional injection molding and screw extrusion techniques. Fluorinated ethylene propylene was invented by DuPont
DuPont
E. I. du Pont de Nemours and Company , commonly referred to as DuPont, is an American chemical company that was founded in July 1802 as a gunpowder mill by Eleuthère Irénée du Pont. DuPont was the world's third largest chemical company based on market capitalization and ninth based on revenue in 2009...

and is sold under the brandname Teflon® FEP. Other brandnames are Neoflon® from Daikin or Dyneon® FEP from Dyneon/3M.

FEP is very similar in composition to the fluoropolymer
Fluoropolymer
A fluoropolymer is a fluorocarbon based polymer with multiple strong carbon–fluorine bonds. It is characterized by a high resistance to solvents, acids, and bases.-History:Fluoropolymers were accidentally discovered in 1938 by Dr. Roy J...

s PTFE (polytetrafluoroethylene)
Polytetrafluoroethylene
Polytetrafluoroethylene is a synthetic fluoropolymer of tetrafluoroethylene that finds numerous applications. PTFE is most well known by the DuPont brand name Teflon....

and PFA (perfluoroalkoxy polymer resin)
Perfluoroalkoxy
Perfluoroalkoxy or PFA is a type of fluoropolymer with properties similar to polytetrafluoroethylene . It differs from the PTFE resins in that it is melt-processable using conventional injection molding and screw extrusion techniques....

. FEP and PFA both share PTFE's useful properties of low friction and non-reactivity, but are more easily formable. FEP is softer than PTFE and melts at 260 °C; it is highly transparent and resistant to sunlight.

## Properties

Useful comparison tables of PTFE against FEP, PFA
Perfluoroalkoxy
Perfluoroalkoxy or PFA is a type of fluoropolymer with properties similar to polytetrafluoroethylene . It differs from the PTFE resins in that it is melt-processable using conventional injection molding and screw extrusion techniques....

and ETFE
ETFE
Ethylene tetrafluoroethylene, ETFE, a fluorine based plastic, was designed to have high corrosion resistance and strength over a wide temperature range. ETFE is a polymer, and its systematic name is poly. ETFE has a very high melting temperature, excellent chemical, electrical and high energy...

can be found on DuPonts website, listing the mechanical, thermal, chemical, electrical and vapour properties of each, side by side.

In terms of corrosion resistance, FEP is the only other readily available fluoropolymer that can match PTFE's own resistance to caustic agents, as it is a pure carbon-fluorine structure and fully fluorinated .

Thermally, FEP stands out from PTFE and PFA by having a melting point of 260 °C (500 °F), around forty degrees lower than PFA and lower again than PTFE .

Electrically, PTFE, FEP and PFA have identical dielectric constants, but FEP's dielectric strength is only surpassed by PFA. However, whilst PFA has a similar dissipation factor to PTFE, FEP's dissipation is around six times that of PFA and EFTE (making it a more non-linear conductor of electrostatic fields) .

Mechanically, FEP is slightly more flexible than PTFE. Perhaps surprisingly, it does not withstand repetitive folding as well as PTFE. It also features a poorer co-efficient of dynamic friction, is softer and has a slightly lower tensile strength than PTFE and FAP .

A noteworthy property of FEP is that it is vastly superior to PTFE in some applications involving exposure to detergents n

ETFE
ETFE
Ethylene tetrafluoroethylene, ETFE, a fluorine based plastic, was designed to have high corrosion resistance and strength over a wide temperature range. ETFE is a polymer, and its systematic name is poly. ETFE has a very high melting temperature, excellent chemical, electrical and high energy...

, in many ways, can be thought of as belonging to a different group, as it is essentially a high strength engineering version of the others featuring what are likely to be considered slightly diminished properties in the other fields when compared with PTFE, FEP and PFA .

## Applications

Due to its flexibility, extreme resistance to chemical attack and optical transparency, this material, along with PFA
Perfluoroalkoxy
Perfluoroalkoxy or PFA is a type of fluoropolymer with properties similar to polytetrafluoroethylene . It differs from the PTFE resins in that it is melt-processable using conventional injection molding and screw extrusion techniques....

is routinely used for plastic labware and tubing that involves critical or highly corrosive processes. Brand GmbH, Finemech, Savillex and Nalgene are well known laboratory suppliers that makes extensive use of the two materials.

Another application are sheet linings for chemical equipment where fabric backed PFA sheets (SYMALIT® PFA). The use of a PFA liner allows to replace expensive metals and alloys like Inconel
Inconel
Inconel is a registered trademark of Special Metals Corporation that refers to a family of austenitic nickel-chromium-based superalloys. Inconel alloys are typically used in high temperature applications. It is often referred to in English as "Inco"...

or Hastelloy
Hastelloy
Hastelloy is the registered trademark name of Haynes International, Inc. The trademark is applied as the prefix name of a range of twenty two different highly corrosion-resistant metal alloys loosely grouped by the metallurgical industry under the material term “superalloys” or “high-performance...

with lined carbon steel or lined FRP
Fibre-reinforced plastic
Fibre-reinforced plastic is a composite material made of a polymer matrix reinforced with fibres. The fibres are usually fibreglass, carbon, or aramid, while the polymer is usually an epoxy, vinylester or polyester thermosetting plastic...

. Examples are SYMALIT® PFA lined columns, scrubbers, reactors and pipes which stand harsh environments like concentrated HF and HCl and halogens.
Another application is for Co-axial cables like RG-316
In manufacturing high-quality composite parts, such as in the aerospace industry, FEP film can be used to protect molds during the curing process. In such applications, the film is called "release film" and is intended to prevent the curing adhesive polymer (e.g. the epoxy in a carbon fibre/epoxy composite laminate) from bonding to the metal tooling. One example is the A-5000 FEP release film by Richmond Aircraft Products (see link).