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