Polyetherketoneketone (PEKK)

Alternative and trade names
Gapekk™, Kepstan®


PEKK (polyether-ketone-ketone) resins are made from a tailored combination of two monomers (terephthaloyl and isophthaloyl moieties on the left and right, respectively). Its key features include:

  • Outstanding high temperature performance - continuous use temperature 250 – 260°C, short term exposure up to 300°C
  • Very high stiffness, tensile & compressive strength, impact resistance
  • Excellent combustion resistance properties - inherently flame retardant, low level of smoke generation
  • Low smoke toxicity
  • Resistant to virtually all organic and inorganic chemicals (only sensitive to very agressive reagents like fuming sulfuric and nitric acid, methylene chloride)
  • High dielectric strength - good insulating properties
  • High breakdown voltage
  • Tremendous barrier properties (CO2, H2S...etc.)
  • Outstanding control of wear-rate and COF (coefficient of friction)
  • Properties


    Density ρ

    1.28 - 1.31 g/cm³ at 20 °C


    Elastic modulus E

    3.5 - 4.5 GPa at 20 °C

    Elongation A

    12 - 80 % at 20 °C

    Impact strength, Charpy notched Ivnot

    4 - 5 kJ/m² at 20 °C

    Impact strength, Charpy unnotched Iunnot

    60 kJ/m² at 20 °C

    no break

    Max allowed stress σmax

    100 - 140 MPa at 20 °C

    at 4-6% strain


    Coefficient of thermal expansion α

    2E-5 - 3E-5 1/K at 20 °C


    UL 94 V0

    Max service temperature, long Tmaxlong

    260 °C

    Max service temperature, short Tmaxshort

    350 °C

    Melting point Tm

    360 - 395 °C

    Specific heat capacity cp

    1000 - 1020 J/(kg·K) at 20 °C

    Thermal conductivity λ

    0.24 W/(m·K) at 20 °C


    Dielectric constant εr

    2.5 - 3.6 [-] at 20 °C

    Electrical resistivity ρel

    1.00E+14 Ω·m at 20 °C




    Technological properties

    Application areas

    Gears, conveyor elements, bearings, seals

    Processing methods

    Injection molding, extrusion, coating, thermoforming

    This material data has been provided by M-Base.

    All metrics apply to room temperature unless otherwise stated. SI units used unless otherwise stated.
    Equivalent standards are similar to one or more standards provided by the supplier. Some equivalent standards may be stricter whereas others may be outside the bounds of the original standard.