Fluorinated Ethylene Propylene

FEP (fluorinated ethylene propylene) is chemically a copolymer of hexafluoropropylene and tetrafluoroethylene. It was developed as a melt processable version of PTFE. As such, it inherits all the chemical resistance and non-stick properties of PTFE whilst offering the ability to be extruded and thermoformed. Properties include

  • Excellent thermal stability. Retains its properties in temperatures from -200 to 200 Deg C.
  • Chemically inert to almost all chemicals and solvents.
  • Retains its properties even after prolonged exposures to harsh chemical environments.
  • Non-stick quality unsurpassed by any plastic.
  • High transparency with good transmittance of UV rays and visible rays up to 98%.
  • Long term weatherability. Excellent resistance to ozone, sunlight and weather.
  • Lowest refractive index of all plastics provides low light reflection. Refractive index of water. Virtually invisible in water.
  • Non toxic. FDA approved
  • Non porous.
  • Inert to body tissue.
  • Electrical reliability. A low dielectric constant and high dielectric strength.

Trade Names for FEP resins include DuPont Teflon™, Daikin Neoflon™, Dyneon Hostaflon™, NiFlon, Sinoflon.

Property Value Units Method
Mechanical Properties
Tensile Strength, 23°C 2100-3050
Elongation at break, 23°C 240-300 %
Flexural Strength, 23°C No break at flexure D 790
Impact Strength, Izod No break
Yield Strength At 23°C 1740
Density 2.12-2.17 gm/cu.cm
Thermal Properties
Coefficient of Linear Expansion 20-100 °C 12 x 10-5 K-1 D 696
Melting Point 253-282 °C
Thermal Conductivity 1.45
Btu/hr-.ft-deg F
W/m/deg K
Service Temperature -250-200 °C
Processing Temperature 370-395 °C
Electrical Properties
Dielectric Strength, short time, 2mm MV m-1
Surface Arc-Resistance >300
(does not track)
sec D 495
Volume Resistivity, dry, @ 50% RH >1018 ohm-cm D 257
Surface Resistivity, @ 100% RH 1016 Ohm/sq D 257
Dielectric Constant, 60 to 2 x 109 cps 2.1 ε D150-81
Dielectric Strength 13-100 kV mm-1 D149
Dissipation Factor @ 60 Hz – 1 MHz <0.0001 D150-81
Other Properties
Refractive Index 1.344 nD 25 D 542
Water Absorption <0.1 % D570-81
Flame Rating+ VE-0 UL-94
Limiting Oxygen Index 95 % Oxygen D 2863
Resistance to Weathering Excellent
Specific Gravity 2.1-2.3 D792-66
Coefficient of friction 0.27–0.67 D 1894

Case Study

Elan Vital UK

Elan Vital UK were looking to develop an apparatus to analyse breath with the aim of early detection of health problems. This necessitated the patient blowing into...

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