Unfilled PEEK
Unfilled PEEK is a grade of PEEK. It has the lowest strength and highest ductility compared to the other variants of PEEK. The graph bars on the material properties cards below compare unfilled 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 MPa 17 x 103 psi
Elastic (Young's, Tensile) Modulus
4.0 GPa 0.58 x 106 psi
Elongation at Break
43 %
Flexural Modulus
3.8 GPa 0.55 x 106 psi
Flexural Strength
150 MPa 21 x 103 psi
Impact Strength: Notched Izod
120 J/m 2.2 ft-lb/in
Rockwell R Hardness
120
Shear Strength
50 MPa 7.3 x 103 psi
Tensile Strength: Ultimate (UTS)
97 MPa 14 x 103 psi
Thermal Properties
Glass Transition Temperature
240 °C 460 °F
Heat Deflection Temperature At 1.82 MPa (264 psi)
160 °C 320 °F
Heat Deflection Temperature At 455 kPa (66 psi)
250 °C 480 °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
1700 J/kg-K 0.41 BTU/lb-°F
Thermal Conductivity
0.25 W/m-K 0.14 BTU/h-ft-°F
Thermal Expansion
52 µm/m-K
Vicat Softening Temperature
250 °C 480 °F
Electrical Properties
Dielectric Constant (Relative Permittivity) At 1 Hz
3.3
Dielectric Constant (Relative Permittivity) At 1 MHz
3.3
Dielectric Strength (Breakdown Potential)
20 kV/mm 0.78 V/mil
Electrical Dissipation At 1 Hz
0.0030
Electrical Dissipation At 1 MHz
0.0030
Electrical Resistivity Order of Magnitude
14 10x Ω-m
Otherwise Unclassified Properties
Density
1.3 g/cm3 82 lb/ft3
Limiting Oxygen Index (LOI)
38 %
Water Absorption After 24 Hours
0.3 %
Water Absorption At Saturation
0.5 %
Common Calculations
Stiffness to Weight: Axial
1.7 points
Stiffness to Weight: Bending
40 points
Strength to Weight: Axial
20 points
Strength to Weight: Bending
36 points
Thermal Diffusivity
0.11 mm2/s
Thermal Shock Resistance
34 points
Followup Questions
Further Reading
ASTM F2026: Standard Specification for Polyetheretherketone (PEEK) Polymers for Surgical Implant Applications
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