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20% Glass Fiber (20 GF) PEEK

20 GF PEEK is a grade of PEEK. The graph bars on the material properties cards below compare 20 GF 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

Elongation at Break

2.5 %

Flexural Modulus

6.7 GPa 1.0 x 106 psi

Flexural Strength

190 MPa 28 x 103 psi

Impact Strength: Notched Izod

85 J/m 1.6 ft-lb/in

Tensile Strength: Ultimate (UTS)

120 MPa 18 x 103 psi

Thermal Properties

Glass Transition Temperature

240 °C 460 °F

Heat Deflection Temperature At 1.82 MPa (264 psi)

290 °C 550 °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 J/kg-K 0.33 BTU/lb-°F

Otherwise Unclassified Properties


1.4 g/cm3 89 lb/ft3

Limiting Oxygen Index (LOI)

38 %

Common Calculations

Stiffness to Weight: Axial

1.5 to 10 points

Stiffness to Weight: Bending

36 to 73 points

Strength to Weight: Axial

24 points

Strength to Weight: Bending

38 points

Thermal Diffusivity

0.1 to 0.51 mm2/s

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