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Thermoplastic Polyimide (PI)

Thermoplastic PI is a thermoplastic, further classified an an imide plastic. It can have a moderately high tensile strength among the thermoplastics in the database.

The properties of thermoplastic PI include three common variations. This page shows summary ranges across all of them. For more specific values, follow the links immediately below. The graph bars on the material properties cards further below compare thermoplastic PI to: imide plastics (top), all thermoplastics (middle), and the entire database (bottom). A full bar means this is the highest value in the relevant set. A half-full bar means it's 50% of the highest, and so on.

Mechanical Properties

Elastic (Young's, Tensile) Modulus

3.7 to 20 GPa 0.54 to 2.9 x 106 psi

Elongation at Break

1.8 to 7.5 %

Flexural Modulus

3.8 to 19 GPa 0.55 to 2.8 x 106 psi

Flexural Strength

170 to 330 MPa 24 to 48 x 103 psi

Tensile Strength: Ultimate (UTS)

110 to 220 MPa 16 to 31 x 103 psi

Thermal Properties

Glass Transition Temperature

260 °C 500 °F

Maximum Temperature: Autoignition

600 °C 1110 °F

Maximum Temperature: Decomposition

530 °C 980 °F

Specific Heat Capacity

970 to 1100 J/kg-K 0.23 to 0.26 BTU/lb-°F

Otherwise Unclassified Properties


1.4 to 1.5 g/cm3 86 to 96 lb/ft3

Limiting Oxygen Index (LOI)

35 %

Common Calculations

Stiffness to Weight: Axial

1.5 to 7.9 points

Stiffness to Weight: Bending

37 to 64 points

Strength to Weight: Axial

22 to 42 points

Strength to Weight: Bending

36 to 57 points

Followup Questions

Further Reading

Reinforced Plastics Durability, Geoffrey Pritchard (editor), 1999

SPI Plastics Engineering Handbook of the Society of the Plastics Industry, Inc., 5th ed., Michael L. Berins (editor), 2000

Modern Plastics Handbook, Charles A. Harper (editor), 1999

Plastics Materials, 7th ed., J. A. Brydson, 1999