Polyetheretherketone (PEEK)
PEEK is an otherwise-unclassified thermoplastic material. It can have a moderately high tensile strength among the thermoplastics in the database.
The properties of PEEK include four 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 PEEK to: otherwise unclassified thermoplastics (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
120 to 300 MPa 17 to 44 x 103 psi
Elastic (Young's, Tensile) Modulus
4.0 to 24 GPa 0.58 to 3.5 x 106 psi
Elongation at Break
1.6 to 43 %
Flexural Modulus
3.8 to 19 GPa 0.55 to 2.7 x 106 psi
Flexural Strength
150 to 330 MPa 21 to 47 x 103 psi
Impact Strength: Notched Izod
78 to 120 J/m 1.5 to 2.2 ft-lb/in
Rockwell R Hardness
120
Shear Strength
50 to 100 MPa 7.3 to 15 x 103 psi
Tensile Strength: Ultimate (UTS)
97 to 200 MPa 14 to 30 x 103 psi
Thermal Properties
Glass Transition Temperature
240 °C 460 °F
Heat Deflection Temperature At 1.82 MPa (264 psi)
160 to 300 °C 320 to 580 °F
Maximum Temperature: Autoignition
600 °C 1100 °F
Maximum Temperature: Decomposition
570 °C 1060 °F
Maximum Temperature: Mechanical
330 °C 630 °F
Melting Onset (Solidus)
340 °C 640 °F
Specific Heat Capacity
1390 to 1700 J/kg-K 0.33 to 0.41 BTU/lb-°F
Thermal Conductivity
0.25 to 0.93 W/m-K 0.14 to 0.54 BTU/h-ft-°F
Thermal Expansion
15 to 52 µm/m-K
Other Material Properties
Density
1.3 to 1.5 g/cm3 82 to 93 lb/ft3
Electrical Resistivity Order of Magnitude
3.0 to 14 10x Ω-m
Limiting Oxygen Index (LOI)
38 %
Water Absorption After 24 Hours
0.060 to 0.3 %
Water Absorption At Saturation
0.22 to 0.5 %
Common Calculations
Stiffness to Weight: Axial
1.5 to 10 points
Stiffness to Weight: Bending
36 to 73 points
Strength to Weight: Axial
20 to 41 points
Strength to Weight: Bending
36 to 55 points
Thermal Diffusivity
0.1 to 0.51 mm2/s
Thermal Shock Resistance
34 to 57 points
Followup Questions
Further Reading
ASTM F2026: Standard Specification for Polyetheretherketone (PEEK) Polymers for Surgical Implant Applications
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
Advanced Materials in Automotive Engineering, Jason Rowe (editor), 2012