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Unfilled PEI

Unfilled PEI is a grade of PEI. The graph bars on the material properties cards below compare unfilled PEI 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

Compressive (Crushing) Strength

140 MPa 20 x 103 psi

Elastic (Young's, Tensile) Modulus

3.4 GPa 0.49 x 106 psi

Elongation at Break

34 %

Flexural Modulus

3.4 GPa 0.49 x 106 psi

Flexural Strength

140 MPa 21 x 103 psi

Impact Strength: Notched Izod

55 J/m 1.0 ft-lb/in

Rockwell M Hardness

110

Shear Strength

100 MPa 15 x 103 psi

Tensile Strength: Ultimate (UTS)

110 MPa 16 x 103 psi

Thermal Properties

Glass Transition Temperature

210 °C 420 °F

Heat Deflection Temperature At 1.82 MPa (264 psi)

200 °C 390 °F

Maximum Temperature: Autoignition

530 °C 990 °F

Maximum Temperature: Decomposition

530 °C 980 °F

Maximum Temperature: Mechanical

170 °C 340 °F

Specific Heat Capacity

1220 J/kg-K 0.29 BTU/lb-°F

Thermal Conductivity

0.18 W/m-K 0.1 BTU/h-ft-°F

Thermal Expansion

53 µm/m-K

Electrical Properties

Dielectric Constant (Relative Permittivity) At 1 MHz

3.2

Dielectric Strength (Breakdown Potential)

33 kV/mm 1.3 V/mil

Electrical Resistivity Order of Magnitude

15 10x Ω-m

Otherwise Unclassified Properties

Density

1.3 g/cm3 80 lb/ft3

Limiting Oxygen Index (LOI)

47 %

Water Absorption After 24 Hours

0.25 %

Water Absorption At Saturation

1.3 %

Common Calculations

Stiffness to Weight: Axial

1.5 points

Stiffness to Weight: Bending

39 points

Strength to Weight: Axial

24 points

Strength to Weight: Bending

40 points

Thermal Diffusivity

0.11 mm2/s

Thermal Shock Resistance

44 points

Followup Questions

Further Reading

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