spore: profile
id: pekk
spore_version: 0.2
family: high-performance-polymers
name: Polyetherketoneketone
abbreviation: PEKK
role: structural/insulating polymer
category: polymers
type: high-performance
summary: |
  PEKK is a semi-crystalline PAEK thermoplastic with a high ketone content and a terephthalic/isophthalic copolymer structure. Arkema's Kepstan 7003 datasheet, a grade sold for filament printing, gives a density of 1.29 g/cm3, a glass transition of 162 °C and a melting point of 336 °C; the 8003 grade melts at 360 °C. Parts printed from ThermaX PEKK C filament in an open-chamber printer reached a tensile strength of 93.9 ± 5.5 MPa, but their tensile modulus was 1060.4 MPa, about a quarter of the 4000 MPa datasheet value, so print conditions matter as much as the grade. No flight, atomic-oxygen or UV-ageing number for PEKK was read in this run.
best_for: Stiff, flame-resistant thermoplastic for filament-printed or fibre-reinforced structural parts that must stay rigid at 150 °C and above (LOI 38 %, V-0 at 0.8 mm)
weakest_at: Printed parts, where crystallinity in the printed layers sets strength and ductility (tensile strength fell about 49 % when the top layer crystallized), and where printed stiffness fell far below the datasheet value. No space ageing data.
identity:
  formula: Poly(ether ketone ketone), a semi-crystalline PAEK copolymer of terephthalic and isophthalic moieties
  source: arkema-6000
  where: 'Product description of the Kepstan 6000 series datasheet (Rev Nov 2024): PEKK backbone with a high ketone content and a copolymer structure incorporating terephthalic and isophthalic moieties. No repeat-unit formula or CAS number for PEKK was confirmed on a fetched page; the Wikipedia infobox gives CAS 29658-26-2 but that number is not confirmed for PEKK, so it is not entered.'
tags:
  environments: []
  stresses:
    - extreme-heat
  applications:
    - structures
properties:
  - benchmark: density
    label: Density, Kepstan 7003
    value: 1.29
    unit: g/cm3
    scope: material
    conditions:
      grade: KEPSTAN 7003 (unfilled, pellet)
      test_standard: ISO 1183-1
      temperature: 23 degC
    method: Value in the manufacturer's technical data sheet, Other properties table
    status: ground
    note: The same density, 1.29 g/cm3, is printed for every 7000 and 8000 series grade, and 1.27 g/cm3 for the 6000 series (amorphous).
    source: arkema-7003
    where: Other properties table
  - benchmark: melting_point
    label: Melting temperature, Kepstan 8003
    value: 360
    unit: °C
    scope: material
    conditions:
      grade: KEPSTAN 8003 (high flow, 8000 series)
      test_standard: DSC, 20 °C/min, 2nd heating
    method: Value in the manufacturer's technical data sheet, Thermal properties table
    status: ground
    note: The 8001 grade is 355 °C and the 8002 grade 360 °C in the 8000 series sheet.
    source: arkema-8003
    where: Thermal properties table
  - benchmark: melting_point
    label: Melting temperature, Kepstan 7003
    value: 336
    unit: °C
    scope: material
    conditions:
      grade: KEPSTAN 7003 (high flow, 7000 series)
      test_standard: DSC, 20 °C/min, 2nd heating
    method: Value in the manufacturer's technical data sheet, Thermal properties table
    status: ground
    note: The 7001 grade melts at 325 °C; the 7000 series is chosen where a lower melting point and slower crystallization help printing and thermoforming.
    source: arkema-7003
    where: Thermal properties table
  - benchmark: melting_point
    label: Melting temperature, Kepstan 7001
    value: 325
    unit: °C
    scope: material
    conditions:
      grade: KEPSTAN 7001 (very low flow, 7000 series)
      test_standard: DSC, 20 °C/min, 2nd heating
    method: Value in the 7000 series technical data sheet, thermal table
    status: ground
    source: arkema-7000
    where: Material properties table, Thermal, Melting point row
  - benchmark: glass_transition_temperature
    label: Glass transition temperature, Kepstan 8003
    value: 165
    unit: °C
    scope: material
    conditions:
      grade: KEPSTAN 8003
      test_standard: DSC, 20 °C/min
    method: Value in the manufacturer's technical data sheet, Thermal properties table
    status: ground
    note: The 8000 series sheet gives 165 °C for all three grades (8001, 8002 and 8003).
    source: arkema-8003
    where: Thermal properties table
  - benchmark: glass_transition_temperature
    label: Glass transition temperature, Kepstan 7003
    value: 162
    unit: °C
    scope: material
    conditions:
      grade: KEPSTAN 7003
      test_standard: DSC, 20 °C/min
    method: Value in the manufacturer's technical data sheet, Thermal properties table
    status: ground
    source: arkema-7003
    where: Thermal properties table
  - benchmark: glass_transition_temperature
    label: Glass transition temperature, Kepstan 6002 (amorphous)
    value: 158
    unit: °C
    scope: material
    conditions:
      grade: KEPSTAN 6002 (pseudo-amorphous, 6000 series)
      test_standard: DSC, 20 °C/min
      state: amorphous
    method: Value in the 6000 series technical data sheet, thermal table; the sheet says the properties correspond to the amorphous state
    status: ground
    note: The 6000 series has no melting point in the sheet (n/a), so it can be processed as low as 320 to 330 °C.
    source: arkema-6000
    where: Material properties table, Thermal; product description
  - benchmark: heat_deflection_temperature
    label: Heat deflection temperature at 1.8 MPa, Kepstan 7003
    value: 164
    unit: °C
    scope: material
    conditions:
      grade: KEPSTAN 7003
      test_standard: ISO 75-1/-2 at 1.8 MPa
    method: Value in the manufacturer's technical data sheet, Mechanical and thermal properties
    status: ground
    source: arkema-7003
    where: Thermal properties table
  - benchmark: elastic_modulus
    label: Tensile modulus, Kepstan 7003
    value: 4000
    unit: MPa
    scope: material
    conditions:
      grade: KEPSTAN 7003 (injection-moulded specimens)
      test_standard: ISO 527-1/-2 (1BA), 23 °C
    method: Value in the manufacturer's technical data sheet, Mechanical properties table
    status: ground
    source: arkema-7003
    where: Mechanical properties table
  - benchmark: elastic_modulus
    label: Tensile modulus, Kepstan 8002
    value: 3.8
    unit: GPa
    scope: material
    conditions:
      grade: KEPSTAN 8002 (medium flow, 8000 series)
      test_standard: ISO 527-A12, 1 mm/min, 23 °C
    method: Value in the 8000 series technical data sheet, mechanical table
    status: ground
    note: Per the same table, the 8001 grade is 3.6 GPa and the 8003 grade 4.1 GPa.
    source: arkema-8000
    where: Material properties table, Mechanical, Tensile modulus row
  - benchmark: elastic_modulus
    label: Tensile modulus, Kepstan 6002 (amorphous)
    value: 2.9
    unit: GPa
    scope: material
    conditions:
      grade: KEPSTAN 6002 (amorphous)
      test_standard: ISO 527-A12, 1 mm/min, 23 °C
      state: amorphous injection-moulded
    method: Value in the 6000 series technical data sheet, mechanical table
    status: ground
    source: arkema-6000
    where: Material properties table, Mechanical, Tensile modulus row
  - benchmark: elastic_modulus
    label: Tensile modulus of printed PEKK (open-chamber FFF, amorphous top layer)
    value: 1060.4
    unit: MPa
    scope: material
    conditions:
      specimen: FFF-printed PEKK C (ThermaX filament, 3DXTech; the paper says it is believed to be Kepstan 7002), amorphous top-layer specimens
      test: tensile, N = 5
    method: Mean of five specimens reported by the paper, Table 2
    status: ground
    uncertainty: standard deviation 30.6 MPa
    note: Roughly a quarter of the 4000 MPa datasheet value for Kepstan 7003, so the printed part is far less stiff than injection-moulded material.
    source: rodzen2025
    where: Section 5.3 and Table 2
  - benchmark: yield_strength
    label: Tensile yield stress, Kepstan 7003
    value: 110
    value_high: 120
    bound: range
    unit: MPa
    scope: material
    conditions:
      grade: KEPSTAN 7003 (injection-moulded specimens)
      test_standard: ISO 527-1/-2 (1BA), 23 °C
    method: Range in the manufacturer's technical data sheet, Mechanical properties table
    status: ground
    note: The 7000 series sheet prints 100 to 120 MPa for 7003 under the same heading, so the two Arkema sheets differ slightly.
    source: arkema-7003
    where: Mechanical properties table, Yield stress row
  - benchmark: ultimate_tensile_strength
    label: Tensile strength (maximum strength), Kepstan 8002
    value: 116
    unit: MPa
    scope: material
    conditions:
      grade: KEPSTAN 8002 (injection-moulded specimens)
      test_standard: ISO 527-A12, 23 °C
    method: Value in the 8000 series technical data sheet, mechanical table
    status: ground
    note: Tensile strength of the 8001 grade is 110 MPa and the 8003 range 100 to 120 MPa on the same sheet.
    source: arkema-8000
    where: Material properties table, Mechanical, Tensile strength row
  - benchmark: ultimate_tensile_strength
    label: Tensile strength of printed PEKK (open-chamber FFF, amorphous top layer)
    value: 93.9
    unit: MPa
    scope: material
    conditions:
      specimen: FFF-printed PEKK C (ThermaX filament, 3DXTech), amorphous top-layer specimens
      test: tensile, N = 5
    method: Mean of five specimens reported by the paper, Table 2
    status: ground
    uncertainty: standard deviation 5.5 MPa
    note: The paper's abstract gives the same figure. Strain at break was 12.2 ± 1.5 % for these specimens.
    source: rodzen2025
    where: Abstract; Section 5.3 and Table 2
  - benchmark: elongation
    label: Elongation at break, Kepstan 7003
    value: 3
    value_high: 10
    bound: range
    unit: '%'
    scope: material
    conditions:
      grade: KEPSTAN 7003 (injection-moulded specimens)
      test_standard: ISO 527-1/-2 (1BA), 23 °C
    method: Range in the manufacturer's technical data sheet, Mechanical properties table
    status: ground
    source: arkema-7003
    where: Mechanical properties table, Nominal strain at break row
  - benchmark: elongation
    label: Elongation at break, Kepstan 8002
    value: 20
    unit: '%'
    scope: material
    conditions:
      grade: KEPSTAN 8002 (injection-moulded specimens)
      test_standard: ISO 527-A12, 23 °C
    method: Value in the 8000 series technical data sheet, mechanical table
    status: ground
    note: The 8003 grade on the same sheet breaks at 3 to 10 %, so strain at break depends strongly on the flow grade.
    source: arkema-8000
    where: Material properties table, Mechanical, Elongation at break row
  - benchmark: flexural_modulus
    label: Flexural modulus, Kepstan 8002
    value: 3.9
    unit: GPa
    scope: material
    conditions:
      grade: KEPSTAN 8002
      test_standard: ISO 178, 23 °C
    method: Value in the 8000 series technical data sheet, mechanical table
    status: ground
    source: arkema-8000
    where: Material properties table, Flexural modulus row
  - benchmark: flexural_strength
    label: Flexural strength (maximum), Kepstan 8002
    value: 180
    unit: MPa
    scope: material
    conditions:
      grade: KEPSTAN 8002
      test_standard: ISO 178, 23 °C
    method: Value in the 8000 series technical data sheet, mechanical table
    status: ground
    note: The same sheet gives 25 MPa for the 8002 grade at 175 °C, so the flexural strength drops sharply with heat.
    source: arkema-8000
    where: Material properties table, Flexural strength row
  - benchmark: cte
    label: Coefficient of thermal expansion, -100 °C to Tg, Kepstan 8002
    value: 23
    unit: µm/m/K
    scope: material
    conditions:
      grade: KEPSTAN 8002
      method_detail: DMA, tension, average from -100 °C to Tg
    method: Value in the 8000 series technical data sheet, thermal table
    status: ground
    note: Above Tg and up to 300 °C the sheet gives 225 µm/m/K.
    source: arkema-8000
    where: Material properties table, Thermal, Coefficient of thermal expansion row
  - benchmark: specific_heat
    label: Specific heat capacity, Kepstan 7003
    value: 1.02
    unit: J/g/K
    scope: material
    conditions:
      grade: KEPSTAN 7003
      temperature: 23 °C
    method: Value in the manufacturer's technical data sheet, Thermal properties table
    status: ground
    source: arkema-7003
    where: Thermal properties table
  - benchmark: moisture_absorption
    label: Water absorption at equilibrium, 23 °C and 50 % RH, Kepstan 7003
    value: 0.4
    unit: '%'
    scope: material
    conditions:
      grade: KEPSTAN 7003
      test_standard: ISO 62, 23 °C, 50 % RH, equilibrium
    method: Value in the manufacturer's technical data sheet, Other properties table
    status: ground
    note: At equilibrium in immersion the same sheet gives 0.7 %, and after 24 h in 50 % RH 0.05 % for a 2 mm specimen.
    source: arkema-7003
    where: Other properties table, Water absorption rows
  - benchmark: dielectric_strength
    label: Dielectric strength, 100 µm film, Kepstan 7003
    value: 84
    unit: kV/mm
    scope: material
    conditions:
      grade: KEPSTAN 7003
      test_standard: IEC 60243-1, 100 µm thickness
    method: Value in the manufacturer's technical data sheet, Electrical properties table
    status: ground
    source: arkema-7003
    where: Electrical properties table
  - benchmark: dielectric_constant
    label: Relative permittivity, 23 °C and 1 MHz, Kepstan 7003
    value: 3
    unit: '-'
    scope: material
    conditions:
      grade: KEPSTAN 7003
      test_standard: IEC 62631-2-1, 23 °C, 1 MHz
    method: Value in the manufacturer's technical data sheet, Electrical properties table
    status: ground
    source: arkema-7003
    where: Electrical properties table, Relative permittivity row
  - benchmark: dissipation_factor
    label: Loss tangent, 23 °C and 1 kHz, Kepstan 8002
    value: 0.002
    unit: '-'
    scope: material
    conditions:
      grade: KEPSTAN 8002
      test_standard: IEC 60250, 23 °C, 1 kHz
    method: Value in the 8000 series technical data sheet, electrical table
    status: ground
    source: arkema-8000
    where: Electrical table, Loss tangent row
  - benchmark: limiting_oxygen_index
    label: Limiting oxygen index, Kepstan 7003
    value: 38
    unit: '% O2'
    scope: material
    conditions:
      grade: KEPSTAN 7003
      test_standard: ISO 4589-1/-2, nominal thickness 3.2 mm
    method: Value in the manufacturer's technical data sheet, Thermal properties table
    status: ground
    note: The same sheet gives burning behaviour of V-0 at a nominal thickness of 0.8 mm (IEC 60695-11-10).
    source: arkema-7003
    where: Thermal properties table, Limiting oxygen index row
  - benchmark: charpy_notched_impact
    label: Charpy notched impact strength, 23 °C, Kepstan 7003
    value: 4.5
    unit: kJ/m2
    scope: material
    conditions:
      grade: KEPSTAN 7003
      test_standard: ISO 179 1eA, 23 °C
    method: Value in the manufacturer's technical data sheet, Mechanical properties table
    status: ground
    source: arkema-7003
    where: Mechanical properties table, Charpy notched impact row
sources:
  arkema-8000:
    title: 'Technical Data: KEPSTAN 8000 Series (PEKK; 8001, 8002 and 8003)'
    id: Arkema technical data sheet, Rev. Nov 2024
    url: https://hpp.arkema.com/assets/arkema/TDS%20ARKEMA%20KEPSTAN%20serie%208000.pdf
    year: 2024
    kind: datasheet
    license: manufacturer document, linked not reproduced
  arkema-7000:
    title: 'Technical Data: KEPSTAN 7000 Series (PEKK; 7001, 7002 and 7003)'
    id: Arkema technical data sheet, Rev Nov 2024
    url: https://hpp.arkema.com/assets/arkema/TDS%20ARKEMA%20KEPSTAN%20serie%207000.pdf
    year: 2024
    kind: datasheet
    license: manufacturer document, linked not reproduced
  arkema-6000:
    title: 'Technical Data: KEPSTAN 6000 Series (pseudo-amorphous PEKK; 6001, 6002 and 6003)'
    id: Arkema technical data sheet, Rev Nov 2024
    url: https://hpp.arkema.com/assets/arkema/TDS%20ARKEMA%20KEPSTAN%20serie%206000.pdf
    year: 2024
    kind: datasheet
    license: manufacturer document, linked not reproduced
  arkema-7003:
    title: 'KEPSTAN 7003: Polyetherketoneketone pellet or flake, technical data sheet'
    id: Arkema HPP technical data sheet, footer dated 2026-09-29
    url: https://hpp.arkema.com/assets/arkema/TDS_KEPSTAN%C2%AE%207003_en_WW.pdf
    year: 2026
    kind: datasheet
    license: manufacturer document, linked not reproduced
  arkema-8003:
    title: 'KEPSTAN 8003: Polyetherketoneketone pellet or flake, technical data sheet'
    id: Arkema HPP technical data sheet, footer dated 2026-09-29
    url: https://hpp.arkema.com/assets/arkema/TDS_KEPSTAN%C2%AE%208003_en_WW.pdf
    year: 2026
    kind: datasheet
    license: manufacturer document, linked not reproduced
  rodzen2025:
    title: Crystallization and microstructure effects on interlayer performance and ductility of Polyetherketoneketone in open-chamber fused filament fabrication
    id: doi:10.1016/j.mtcomm.2025.114253 (Materials Today Communications 49, 114253)
    url: https://pure.ulster.ac.uk/ws/files/235453217/1-s2.0-S2352492825027655-main.pdf
    year: 2025
    kind: paper
    license: CC BY 4.0
  glaskova2024:
    title: The Tensile, Thermal and Flame-Retardant Properties of Polyetherimide and Polyetherketoneketone Processed via Fused Filament Fabrication
    id: doi:10.3390/polym16030336 (Polymers 16(3), 336)
    url: https://doi.org/10.3390/polym16030336
    year: 2024
    kind: paper
    license: CC BY 4.0
    note: 'Section 3 text of the open-access PDF: versus PEI, PEKK elastic modulus 18.2 % and tensile strength 6.0 % higher at 0 degree raster; at 45 degrees, elastic modulus 41.1 % and tensile strength 104.4 % higher. The paper gives relative figures only.'
  garcia2021:
    title: Characterization of polyaryletherketone (PAEK) filaments and parts printed by extrusion-based additive manufacturing
    id: doi:10.1002/pi.6231 (Polymer International 70(8), 1128-1136)
    url: https://researchdiscovery.drexel.edu/esploro/outputs/journalArticle/Characterization-of-polyaryletherketone-PAEK-filaments-and/991019168382304721
    year: 2021
    kind: paper
    license: publisher record, linked not reproduced
    note: 'Abstract, read through the publisher record: Tg of printed PEEK bars 146.8 °C against 154.8 °C for the parent PEEK filament; no observable difference between PEKK filament and printed bars.'
  wiki-pekk:
    title: Polyetherketoneketone (Wikipedia)
    id: Wikipedia article, accessed 2026-10-26; history, manufacturer and infobox context only
    url: https://en.wikipedia.org/wiki/Polyetherketoneketone
    year: 2026
    kind: web
    license: CC BY-SA 4.0
license: CC-BY-4.0
updated: '2026-10-26'
review:
  status: draft
  method: assistant
  checked_values: 27
  unreachable: 1
  caveats: 4
  note: Written by an AI assistant on 2026-10-26. Values come from the Arkema datasheets and the Rodzen 2025 paper, read as text in this run. The 2016 CF/PEKK ageing paper (SAGE, 403) could not be opened; no Arkema SDS was found.
corrosion:
  - environment: Water vapour and immersion at 23 °C
    headline: PEKK takes up about 0.4 % water at 50 % humidity and 0.7 % in immersion, at equilibrium.
    effect: Equilibrium water absorption is 0.4 % at 23 °C and 50 % relative humidity, and 0.7 % in immersion (ISO 62, KEPSTAN 7003). These are uptake figures; no wet-and-dry ageing test was read in this run.
    rating: low
    conditions:
      grade: KEPSTAN 7003
      test_standard: ISO 62
    source: arkema-7003
    where: Other properties table, Water absorption rows
  - environment: Heat over service life
    headline: No long-term heat-ageing test was found; the datasheets give short-term heat deflection and glass transition only.
    effect: KEPSTAN 7003 has a heat deflection temperature of 164 °C at 1.8 MPa and a glass transition of 162 °C. For the 8002 grade the sheet gives a yield stress of 24 MPa at 175 °C in a short tensile test at 25 mm/min, which is not an ageing result.
    rating: unknown
    conditions:
      basis: short-term tests on datasheets
    source: arkema-8000
    where: Thermal table (heat deflection rows); Mechanical table (tensile strength at HT rows)
  - environment: Ultraviolet light
    headline: No UV-ageing number for PEKK was read; the datasheet only asks for UV-protected storage.
    effect: KEPSTAN 7003 gives an indefinite shelf life when stored sealed with appropriate UV protection and temperature. The 2016 carbon-fibre PEKK ageing paper (J. Thermoplastic Composite Materials, DOI 10.1177/0892705714564283) could not be opened (HTTP 403), so its UV findings are not used.
    rating: unknown
    conditions:
      basis: storage statement only
    source: arkema-7003
    where: Shelf life section
  - environment: Chemicals and solvents
    headline: Arkema describes chemical resistance in general terms only; no chemical-resistance table was read.
    effect: The 8000 series product description cites chemical and fire resistance from the semi-crystalline solid state. No acid, base or solvent test was read in this run.
    rating: unknown
    conditions:
      basis: product description only
    source: arkema-8000
    where: Product description
risks:
  hazards: []
  failure_risks:
    - mode: Brittle interlayer in printed PEKK
      trigger: Top layer of a printed part allowed to crystallize (open-chamber FFF, no top-layer temperature control)
      consequence: Excess crystallization causes brittleness through poor chain entanglement at the layer interface. The paper reports the tensile strength of the crystallized batch was reduced by about 49 % relative to the amorphous top layer.
      severity: moderate
      source: rodzen2025
      where: Abstract; Section 5.3
    - mode: Low stiffness of printed PEKK
      trigger: Fused-filament printing of PEKK C filament, amorphous top layer, tensile test
      consequence: Printed tensile modulus was 1060.4 MPa, against the 4000 MPa datasheet value for injection-moulded Kepstan 7003, so stiffness-critical printed parts need their own test data.
      severity: moderate
      source: rodzen2025
      where: Table 2
    - mode: Strength loss at elevated temperature
      trigger: Tensile test at 175 °C (8002 grade, ISO 527-A12, 25 mm/min)
      consequence: Tensile strength at the yield point falls to 24 MPa at 175 °C, against 116 MPa maximum strength at 23 °C, so a loaded part should stay well below this temperature.
      severity: high
      source: arkema-8000
      where: Material properties table, Mechanical, Tensile strength (yield point) at HT row
  side_effects: []
  handling:
    - text: 'Melt-process the 8000 series at 375 to 385 °C (extrusion and injection), and dry the resin first: 150 °C for 3 to 4 hours, or 120 °C for 6 to 8 hours.'
      source: arkema-8000
      where: Recommended processing conditions
    - text: Store sealed, with UV protection and at a controlled temperature; the 7003 sheet gives an indefinite shelf life under those conditions.
      source: arkema-7003
      where: Shelf life section
  mitigations:
    - text: Keep the top layer below its crystallization threshold and control its temperature (halogen heater on an open-chamber printer) to keep ductility.
      source: rodzen2025
      where: Abstract
uses:
  - application: structures
    device: Fused-filament-printed PEKK parts from an open-chamber printer (ground tests only)
    example: A PEKK C filament was printed without an enclosed chamber and reached 93.9 ± 5.5 MPa tensile strength in the amorphous-top-layer condition, with the authors claiming comparable results to enclosed systems.
    source: rodzen2025
    where: Abstract; Section 5.3
  - application: structures
    device: Continuous-fibre composites and filament printing with the 7000 series grades (manufacturer application statement)
    example: Arkema says the 7000 series is 'highly enabling' for continuous fibre composites for structural applications and for filament additive manufacturing, with or without continuous fibres.
    source: arkema-7000
    where: Product description
supply:
  - subject: PEKK polymer (Kepstan)
    producers: []
    source: arkema-8000
    where: Arkema France, Colombes (France), named in the datasheet footer. No country shares for PEKK resin were read. Filament-grade PEKK C was bought from 3DXTech (Michigan, USA) per Rodzen 2025, Section 3.1.
documents:
  - title: KEPSTAN 8000 Series technical data sheet (Rev Nov 2024)
    type: datasheet
    url: https://hpp.arkema.com/assets/arkema/TDS%20ARKEMA%20KEPSTAN%20serie%208000.pdf
    year: 2024
  - title: KEPSTAN 7000 Series technical data sheet (Rev Nov 2024)
    type: datasheet
    url: https://hpp.arkema.com/assets/arkema/TDS%20ARKEMA%20KEPSTAN%20serie%207000.pdf
    year: 2024
  - title: KEPSTAN 6000 Series technical data sheet (Rev Nov 2024)
    type: datasheet
    url: https://hpp.arkema.com/assets/arkema/TDS%20ARKEMA%20KEPSTAN%20serie%206000.pdf
    year: 2024
  - title: KEPSTAN 7003 technical data sheet
    type: datasheet
    url: https://hpp.arkema.com/assets/arkema/TDS_KEPSTAN%C2%AE%207003_en_WW.pdf
    year: 2026
  - title: KEPSTAN 8003 technical data sheet
    type: datasheet
    url: https://hpp.arkema.com/assets/arkema/TDS_KEPSTAN%C2%AE%208003_en_WW.pdf
    year: 2026
  - title: Crystallization and microstructure effects on interlayer performance and ductility of PEKK in open-chamber FFF (open access)
    type: paper
    url: https://pure.ulster.ac.uk/ws/files/235453217/1-s2.0-S2352492825027655-main.pdf
    year: 2025
  - title: The Tensile, Thermal and Flame-Retardant Properties of PEI and PEKK Processed via FFF (open access)
    type: paper
    url: https://doi.org/10.3390/polym16030336
    year: 2024
  - title: Characterization of PAEK filaments and parts printed by extrusion-based additive manufacturing
    type: paper
    url: https://researchdiscovery.drexel.edu/esploro/outputs/journalArticle/Characterization-of-polyaryletherketone-PAEK-filaments-and/991019168382304721
    year: 2021
gaps:
  - No media (images) were added to this profile; no PEKK picture with a checked licence was read in this run.
  - No Arkema safety data sheet or PubChem GHS record for PEKK was read, so hazards is empty. The datasheets give no hazard classification and point to other documents.
  - No CAS number is entered. The Wikipedia infobox gives 29658-26-2, but I could not confirm it for PEKK on a second page, and no PubChem record was found.
  - No repeat-unit formula, monomer atoms or monomer supply was read; the recipe below uses the copolymer description only.
  - No atomic-oxygen erosion, outgassing (ECSS), vacuum, radiation or flight result for PEKK was found. Search returned only PEEK and PEI flight records.
  - No UV-ageing or long-term heat-ageing number for PEKK was read. The 2016 CF/PEKK ageing paper (J. Thermoplastic Composite Materials, DOI 10.1177/0892705714564283) returned HTTP 403 at SAGE, so only a search snippet was seen and it is not used.
  - No country shares, feedstock source or critical-mineral listing for PEKK was found; only the Arkema head office is documented.
  - PEK (polyetherketone) was not covered. The Victrex PEK search returned only PEEK grades 90G and 151G, which are PEEK, not PEK.
  - The two Arkema sheets disagree on some values (7003 yield stress 110 to 120 MPa against 100 to 120 MPa on the 7000 series sheet; volume resistivity given in different units). Only the standalone 7003 values are entered for the 7003 grade, and the volume resistivity is left out.
  - Printed PEKK values come from one filament (ThermaX PEKK C, believed to be Kepstan 7002, per the paper) and one printer, so they are not a datasheet grade.
  - Garcia et al. 2021 (PEEK and PEKK printed parts) gave no PEKK numbers in its abstract, only the statement that printed PEKK shows no difference from the filament; its PEEK numbers are used only in the comparison text.
  - limiting_oxygen_index and charpy_notched_impact are not canonical property names in property-canon.yaml; they are kept as snake_case names for this profile.
  - Elevated-temperature strength is taken from one 8002 row (175 °C yield strength); no 125 °C or 175 °C value is entered as a benchmark.
  - A 2026 FFF PEKK biomedical paper (UCL, Biomaterials Advances) is restricted to UCL staff until 12 August 2026 and was not read.
  - The Kimya PEKK-A filament page returned no property table (behind a sign-in), so it is not used.
story:
  recipe:
    line: PEKK is a poly(aryl ether ketone ketone) copolymer. Arkema builds its Kepstan grades on a PEKK backbone with a high ketone content and a copolymer of terephthalic and isophthalic units, with the ratio setting crystallization speed (6000 series amorphous, 7000 and 8000 series semi-crystalline). The chain is stiff because of the aromatic rings and ketone links.
    parts:
      - name: Terephthalic moiety
        symbol: T
        role: Para-linked aromatic unit in the copolymer. It favours a more regular chain and faster crystallization.
      - name: Isophthalic moiety
        symbol: I
        role: Meta-linked aromatic unit. It lowers crystallinity and slows crystallization, which is why the 6000 series is pseudo-amorphous.
      - name: Ether and ketone links
        symbol: O, CO
        role: Ether links give flexibility of the chain; ketone links give the high-temperature stiffness.
  risk_groups:
    - title: For people
      level: 0
      verdict: Not classified in the sources read
      lead: No Arkema safety data sheet was read, so there is no hazard classification for the resin, only processing guidance.
      points:
        - label: The resin
          line: The datasheets describe handling and processing only. They give no toxicology or hazard statements, so treat the resin as unknown rather than safe.
        - label: Melt
          line: The 8000 series is processed at 375 to 385 °C, so hot polymer and fume from melting are a concern. The sources read do not give fume or burn data.
    - title: If a part fails
      lead: These results come from printed test coupons and datasheet tests, not from failures of finished parts.
      points:
        - label: Printed layers
          line: When the top layer of a printed part crystallized, tensile strength fell by about 49 %, because the layer interface became brittle.
        - label: Printed stiffness
          line: Printed tensile modulus was 1060.4 MPa, far below the 4000 MPa of injection-moulded Kepstan 7003.
        - label: Heat
          line: Tensile strength at the yield point fell to 24 MPa at 175 °C for the 8002 grade, against 116 MPa maximum strength at 23 °C.
    - title: Handling and storage
      points:
        - label: Drying
          line: Dry the pellets before processing, at 150 °C for 3 to 4 hours or 120 °C for 6 to 8 hours.
        - label: Storage
          line: Keep the resin sealed and UV-protected; Arkema gives an indefinite shelf life under those conditions.
  why: PEKK is a semi-crystalline thermoplastic in the PAEK family. Its ketone-rich chain and aromatic rings keep it stiff at high temperature, and the choice of terephthalic and isophthalic units sets how fast it crystallizes. That lets one family cover amorphous grades for low-temperature processing and semi-crystalline grades for stiffness. The Kepstan 7000 series is sold for filament printing, because its slower crystallization eases interlayer adhesion, and the same paper family reports that PEKK keeps no observable difference between filament and printed parts, while PEEK loses some glass transition on printing.
  uses:
    - where: Printed structural parts
      line: Printed PEKK C filament reached a tensile strength of 93.9 MPa in an open-chamber printer, which the authors compare with enclosed systems. These are ground test coupons, not flight parts.
    - where: Composite and filament structures
      line: Arkema describes the 7000 series as highly enabling for continuous-fibre composite structures and for filament additive manufacturing. The datasheet does not name a specific part.
  can_do:
    - label: Stiffness
      value: 4000 MPa
      line: The 7003 grade has a tensile modulus of 4000 MPa and a yield stress of 110 to 120 MPa at 23 °C, from injection-moulded specimens. The printed PEKK in the Rodzen paper was far less stiff, at 1060.4 MPa.
    - label: Heat
      value: 162 °C glass transition
      line: The 7003 grade has a glass transition of 162 °C and a heat deflection temperature of 164 °C at 1.8 MPa. The 8003 grade melts at 360 °C and has a glass transition of 165 °C.
    - label: Fire
      value: V-0 at 0.8 mm
      line: The 7003 sheet gives a limiting oxygen index of 38 % and a V-0 rating at a nominal thickness of 0.8 mm (IEC 60695-11-10).
    - label: Printed strength
      value: 93.9 MPa
      line: Printed PEKK C in the amorphous top-layer condition reached 93.9 ± 5.5 MPa tensile strength, with 12.2 ± 1.5 % strain at break.
  compare: Against PEI, the Glaskova study found PEKK stiffer and stronger when printed at a 0 degree raster angle (18.2 % and 6.0 % higher in modulus and strength) and much stronger at 45 degrees (41.1 % higher modulus and 104.4 % higher tensile strength), with more uniform behaviour across print directions. Against PEEK, the Garcia 2021 study found that printed PEEK bars had a glass transition of 146.8 °C, about 8 °C below the 154.8 °C of the parent filament, while printed PEKK showed no observable difference from its filament. Arkema's 6000 series also states a high ketone content and a copolymer structure, which is how PEKK differs from PEEK in chemistry, but no PEEK value from the same run is used here.
  compare_rows:
    - label: Density
      benchmark: density
    - label: Melting point
      benchmark: melting_point
    - label: Tensile modulus
      benchmark: elastic_modulus
  handling:
    - Dry the pellets before melt processing; 150 °C for 3 to 4 hours is the datasheet's first option.
    - Keep the resin sealed and UV-protected in storage.
    - Control the top-layer temperature of printed parts to keep the layer ductile.
    - Do not use the datasheet numbers as design values for printed parts without test data.
  good_for:
    - Stiffness at temperature. The 7003 grade has a tensile modulus of 4000 MPa and a glass transition of 162 °C.
    - Flame resistance. A limiting oxygen index of 38 % and V-0 at 0.8 mm.
    - Printed parts with control. Printed PEKK reached 93.9 MPa when the top layer stayed amorphous.
  watch_out:
    - Printed stiffness. Printed PEKK had a tensile modulus of 1060.4 MPa against 4000 MPa for injection-moulded material.
    - Crystallized top layers. Tensile strength fell by about 49 % when the top layer crystallized.
    - Heat. Tensile strength at the yield point fell to 24 MPa at 175 °C for the 8002 grade.
    - Ageing. No UV or long-term heat-ageing number for PEKK was found, so long service in sunlight or hot environments is untested.
  verdict: PEKK is a stiff, flame-resistant, heat-tolerant thermoplastic with good datasheet properties, but the printed-part numbers are much lower than the datasheet. Test printed parts directly before using them in a load-bearing design, and treat any space use as untested.