Phenolic vs. Thermoset PI

Both phenolic and thermoset PI are thermoset plastics. There are 17 material properties with values for both materials. Properties with values for just one material (11, in this case) are not shown.

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

Phenol Formaldehyde (PF, Phenolic)Thermoset Polyimide (PI)

Metric UnitsUS Customary Units

Mechanical Properties

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

Tensile Strength: Ultimate (UTS), MPa		48
Tensile Strength: Ultimate (UTS), MPa		37 to 81

Thermal Properties

Glass Transition Temperature, °C		170
Glass Transition Temperature, °C		360

Maximum Temperature: Autoignition, °C		430
Maximum Temperature: Autoignition, °C		380

Maximum Temperature: Decomposition, °C		260
Maximum Temperature: Decomposition, °C		330

Maximum Temperature: Mechanical, °C		150
Maximum Temperature: Mechanical, °C		260

Specific Heat Capacity, J/kg-K		1400
Specific Heat Capacity, J/kg-K		1130

Thermal Conductivity, W/m-K		0.25
Thermal Conductivity, W/m-K		0.29 to 1.7

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

Electrical Properties

Dielectric Constant (Relative Permittivity) At 1 MHz		7.5
Dielectric Constant (Relative Permittivity) At 1 MHz		3.1

Dielectric Strength (Breakdown Potential), kV/mm		46
Dielectric Strength (Breakdown Potential), kV/mm		20

Electrical Resistivity Order of Magnitude, 10^x Ω-m		11
Electrical Resistivity Order of Magnitude, 10^x Ω-m		15

Otherwise Unclassified Properties

Density, g/cm³		1.3
Density, g/cm³		1.4 to 1.6

Limiting Oxygen Index (LOI), %		27
Limiting Oxygen Index (LOI), %		40

Common Calculations

Strength to Weight: Axial, points		10
Strength to Weight: Axial, points		6.5 to 16

Strength to Weight: Bending, points		23
Strength to Weight: Bending, points		16 to 30

Thermal Diffusivity, mm²/s		0.14
Thermal Diffusivity, mm²/s		0.18 to 0.95