FEP vs. PTFE

Both FEP and PTFE are thermoplastics. There are 17 material properties with values for both materials. Properties with values for just one material (14, in this case) are not shown.

For each property being compared, the top bar is FEP and the bottom bar is PTFE.

Fluorinated Ethylene Propylene (FEP)Polytetrafluoroethylene (PTFE)

Metric UnitsUS Customary Units

Mechanical Properties

Elongation at Break, %		300
Elongation at Break, %		75 to 300

Flexural Modulus, GPa		0.6
Flexural Modulus, GPa		0.4 to 1.3

Flexural Strength, MPa		24
Flexural Strength, MPa		13 to 50

Tensile Strength: Ultimate (UTS), MPa		20
Tensile Strength: Ultimate (UTS), MPa		13 to 25

Thermal Properties

Heat Deflection Temperature At 1.82 MPa (264 psi), °C		50
Heat Deflection Temperature At 1.82 MPa (264 psi), °C		66 to 70

Maximum Temperature: Mechanical, °C		200
Maximum Temperature: Mechanical, °C		260 to 270

Melting Onset (Solidus), °C		260
Melting Onset (Solidus), °C		330 to 340

Thermal Conductivity, W/m-K		0.22
Thermal Conductivity, W/m-K		0.24 to 0.65

Thermal Expansion, µm/m-K		95
Thermal Expansion, µm/m-K		110 to 120

Electrical Properties

Dielectric Constant (Relative Permittivity) At 1 MHz		2.0
Dielectric Constant (Relative Permittivity) At 1 MHz		2.1 to 2.4

Electrical Dissipation At 1 MHz		0.00065
Electrical Dissipation At 1 MHz		0.00017 to 0.050

Electrical Resistivity Order of Magnitude, 10^x Ω-m		16
Electrical Resistivity Order of Magnitude, 10^x Ω-m		2.0 to 18

Otherwise Unclassified Properties

Density, g/cm³		2.1
Density, g/cm³		2.1 to 2.3

Limiting Oxygen Index (LOI), %		80
Limiting Oxygen Index (LOI), %		90

Water Absorption After 24 Hours, %		0.010
Water Absorption After 24 Hours, %		0.0093 to 0.050

Common Calculations

Strength to Weight: Axial, points		2.6
Strength to Weight: Axial, points		1.7 to 3.2

Strength to Weight: Bending, points		7.6
Strength to Weight: Bending, points		5.7 to 8.7