Thermoset PI vs. PTFE

Thermoset PI belongs to the thermoset plastics classification, while PTFE belongs to the thermoplastics. There are 16 material properties with values for both materials. Properties with values for just one material (10, in this case) are not shown.

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

Thermoset Polyimide (PI)Polytetrafluoroethylene (PTFE)

Metric UnitsUS Customary Units

Mechanical Properties

Compressive (Crushing) Strength, MPa		120 to 210
Compressive (Crushing) Strength, MPa		6.9 to 24

Elongation at Break, %		2.0 to 5.9
Elongation at Break, %		75 to 300

Flexural Modulus, GPa		3.1 to 4.8
Flexural Modulus, GPa		0.4 to 1.3

Flexural Strength, MPa		60 to 100
Flexural Strength, MPa		13 to 50

Tensile Strength: Ultimate (UTS), MPa		37 to 81
Tensile Strength: Ultimate (UTS), MPa		13 to 25

Thermal Properties

Heat Deflection Temperature At 1.82 MPa (264 psi), °C		370
Heat Deflection Temperature At 1.82 MPa (264 psi), °C		66 to 70

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

Thermal Conductivity, W/m-K		0.29 to 1.7
Thermal Conductivity, W/m-K		0.24 to 0.65

Thermal Expansion, µm/m-K		38 to 54
Thermal Expansion, µm/m-K		110 to 120

Electrical Properties

Dielectric Constant (Relative Permittivity) At 1 MHz		3.1
Dielectric Constant (Relative Permittivity) At 1 MHz		2.1 to 2.4

Electrical Resistivity Order of Magnitude, 10^x Ω-m		15
Electrical Resistivity Order of Magnitude, 10^x Ω-m		2.0 to 18

Otherwise Unclassified Properties

Density, g/cm³		1.4 to 1.6
Density, g/cm³		2.1 to 2.3

Limiting Oxygen Index (LOI), %		40
Limiting Oxygen Index (LOI), %		90

Water Absorption After 24 Hours, %		0.14 to 0.24
Water Absorption After 24 Hours, %		0.0093 to 0.050

Common Calculations

Strength to Weight: Axial, points		6.5 to 16
Strength to Weight: Axial, points		1.7 to 3.2

Strength to Weight: Bending, points		16 to 30
Strength to Weight: Bending, points		5.7 to 8.7