PEKK · grade · default condition
PEKK Unfilled
Properties of the Unfilled condition, compared with the other PEKK grades.
Default choice for ductile, low-outgassing, flame-retardant parts where isotropy and toughness matter more than stiffness.
What is PEKK Unfilled?
PEKK Unfilled is PEKK in the Unfilled grade — default choice for ductile, low-outgassing, flame-retardant parts where isotropy and toughness matter more than stiffness. PEKK Unfilled has a yield strength of 95 MPa (13.8 ksi) and a tensile strength of 95 MPa (13.8 ksi) — stronger than 93% of polymer grades. Elongation at break is 8% and the elastic modulus is 3.9 GPa (0.566 Msi). PEKK Unfilled has a density of 1.3 g/cm³ (0.047 lb/in³), heavier than 69% of polymer grades. Its glass-transition temperature is 162°C (324 °F).
Advantages
- High strength — 95 MPa (13.8 ksi), better than 93% of polymer grades
- High service temperature — 240°C (464 °F), better than 92% of polymer grades
- Good corrosion resistance — 92/100, better than 91% of polymer grades
- Stiff — 3.9 GPa (0.566 Msi), better than 85% of polymer grades
- Tough — resists crack growth — 3.5 MPa·√m (3.19 ksi·√in), better than 80% of polymer grades
Limitations
- High embodied carbon — 18 kg CO₂/kg, worse than 99% of polymer grades
PEKK Unfilled properties
Typical room-temperature values for PEKK Unfilled — 12 properties are specific to this condition; the rest are grade-level values shared by every PEKK grade. Each bar shows where the value sits among the polymer grades in FabDigit's library — further right is higher.
Physical5
PEKK Unfilled has a density of 1.3 g/cm³ (0.047 lb/in³), heavier than 69% of polymer grades. Its glass-transition temperature is 162°C (324 °F).
Mechanical16
PEKK Unfilled has a yield strength of 95 MPa (13.8 ksi) and a tensile strength of 95 MPa (13.8 ksi) — stronger than 93% of polymer grades. Elongation at break is 8% and the elastic modulus is 3.9 GPa (0.566 Msi).
Thermal10
PEKK Unfilled is rated for continuous service to 240°C (464 °F). It conducts heat at 0.26 W/m·K (0.15 BTU/hr·ft·°F), better than 76% of polymer grades. Thermal expansion is 48 µm/m·K (26.7 µin/in·°F).
Electrical7
PEKK Unfilled is an electrical insulator with a dielectric strength of 22 kV/mm (558.8 V/mil) and a resistivity of 1×10¹⁴ Ω·m.
Chemical & Environmental3
Corrosion resistance is excellent (92/100), better than 91% of polymer grades. UV resistance is fair.
Sustainability4
Producing a kilogram of PEKK Unfilled takes about 330 MJ of energy and emits 18 kg of CO₂ — more than 99% of polymer grades. Typical recycled content is 0%.
Manufacturability7
PEKK Unfilled's machinability is good (60/100, better than 51% of polymer grades); weldability good (55/100); formability fair (35/100).
Common Calculations5
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Other PEKK grades and fills
PEKK is also supplied in 9 other conditions. The full side-by-side table is on the PEKK overview.
- UnfilledDefaultDefault choice for ductile, low-outgassing, flame-retardant parts where isotropy and toughness matter more than stiffness.95 MPa tensile
- GF30Pick for stiff, creep-resistant, electrically insulating parts at elevated temperature at lower cost than carbon fiber.160 MPa tensile
- CFUse where maximum stiffness, dimensional stability and low CTE are needed (aerospace brackets, tooling); sacrifices ductility and abrades tooling.145 MPa tensile
- FFFPick when quoting as-printed extruded parts; expect strong anisotropy with Z-direction roughly 60–70 % of in-plane strength.93 MPa tensile
- ESDUse for satellite, fuel-system and electronics-handling parts requiring controlled surface resistivity without sacrificing PEKK's heat and FST behaviour.87 MPa tensile
Working with PEKK Unfilled
Is PEKK easy to machine?
Machines like PEEK with sharp carbide/PCD tools, high speed, light feeds and air or flood cooling; stress-relieve (annealing near 200 °C) before finish cuts to avoid distortion.
Can PEKK be welded?
Joinable by laser, ultrasonic, IR and hot-plate welding as well as PAEK-compatible epoxy adhesives after plasma or abrasive surface activation; no solvent bonding.
Can PEKK be formed, bent or molded?
Requires 340–420 °C melt, 160–230 °C tools and dry feedstock (<0.02 % moisture, 150 °C for 3–4 h); FFF needs a 400 °C-class hot end plus 130–200 °C chamber and post-print anneal for crystallinity and Z-strength.
What surface finishes work on PEKK?
Sand/bead-blast or vapour-smooth-free finishing only; no anodizing — parts can be painted or metallised after plasma treatment, and machined surfaces polish to a semi-gloss tan finish.
PEKK chemical composition (wt %)
Limits by weight percent from the governing specification, written the way the spec states them — a single maximum for impurities, a range for alloying elements, and the base element as balance. Nominal is the typical mid-range value.
| Element | Spec limit (wt %) | Nominal |
|---|---|---|
| carbon fiberCF variants only | 0 – 30 | 0 |
| glass fiberGF variants only | 0 – 40 | 0 |
| carbon nanotubeESD variant only | 0 – 5 | 0 |
| polyetherketoneketone repeat unit (from T/I isomer ratio ~60:40 to 80:20 sets Tm; unfilled default | balance | — |
PEKK Unfilled — frequently asked
What is PEKK Unfilled used for?
PEKK Unfilled is typically used for aerospace brackets, air and fluid ducting, satellite components, aerospace composite tooling and structures, electrical insulation parts and implantable orthopaedic devices. In short: space-grade performance.
What is the yield strength of PEKK Unfilled?
PEKK Unfilled has a typical yield strength of 95 MPa (13.8 ksi) and a tensile strength of 95 MPa (13.8 ksi) — stronger than 93% of polymer grades. Strength varies by condition: see the 10 listed tempers.
Is PEKK Unfilled easy to machine?
Reasonably — machinability is rated good (60/100, better than 51% of polymer grades). Machines like PEEK with sharp carbide/PCD tools, high speed, light feeds and air or flood cooling; stress-relieve (annealing near 200 °C) before finish cuts to avoid distortion.
Can PEKK Unfilled be welded?
Yes — weldability is rated good (55/100). Joinable by laser, ultrasonic, IR and hot-plate welding as well as PAEK-compatible epoxy adhesives after plasma or abrasive surface activation; no solvent bonding.
What surface finishes work on PEKK Unfilled?
Sand/bead-blast or vapour-smooth-free finishing only; no anodizing — parts can be painted or metallised after plasma treatment, and machined surfaces polish to a semi-gloss tan finish.
Can PEKK Unfilled be formed, bent or molded?
Requires 340–420 °C melt, 160–230 °C tools and dry feedstock (<0.02 % moisture, 150 °C for 3–4 h); FFF needs a 400 °C-class hot end plus 130–200 °C chamber and post-print anneal for crystallinity and Z-strength.
What is the maximum service temperature of PEKK Unfilled?
PEKK Unfilled is rated for continuous use to about 240°C (464 °F), and briefly to 300°C. Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
Can FabDigit make parts in PEKK Unfilled?
Yes — PEKK Unfilled is available for 3D printing with instant online pricing. Upload a STEP file to get a price and a DFM check.
Sources
- Kepstan PEKK 6000/7000/8000 series technical data and processing guide — Arkema (2022)
- Antero 800NA and Antero 840CN03 PEKK FDM material datasheets — Stratasys (2023)
- Engineering Plastics — polyaryletherketone property overview — ASM International (2000)
- CAMPUS / UL Prospector PAEK property listings — CWFG / UL Solutions (2024)
- ISO 10993 series (biological evaluation of medical devices) — ISO (2018)
Property data is compiled from published supplier and standards handbooks and normalised for comparison. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.