Vespel SP-3 (15 % MoS2 polyimide) SP-3

spore: profile
id: vespel-sp-3
spore_version: 0.2
family: polyimides
name: Vespel SP-3 (15 % MoS2 polyimide)
abbreviation: SP-3
role: self-lubricating bearing and seal material for vacuum and dry running
category: tribology
type: dry-lubricants
summary: |
  Vespel SP-3 is a DuPont polyimide grade filled with 15 % molybdenum disulfide (MoS2), sold as isostatic shapes and machined parts for seals and bearings in vacuum or dry environments (DuPont product information sheet). The DuPont typical properties table gives a tensile strength of 58.5 MPa and a strain at break of 4.0 % at 23 °C (ASTM D-1708 or E8), and a friction coefficient of 0.03 in vacuum against 0.25 in air at PV 0.875 MPa·m/s. Its flexural modulus falls from 3275 MPa at 23 °C to 1862 MPa at 260 °C (ASTM D-790), and the DuPont safety data sheet lists combustible dust as its only hazard category.
best_for: 'Dry-running or vacuum bearings and seals: a typical friction coefficient of 0.03 in vacuum (DuPont)'
weakest_at: 'Stiffness and strength at high temperature: flexural modulus 1862 MPa at 260 °C against 3275 MPa at 23 °C (DuPont)'
identity:
  formula: Polyimide made from pyromellitic dianhydride and 4,4'-oxydianiline, filled with 15 % molybdenum disulfide (MoS2)
  source: dupont-sp3-pis
  where: Title and opening paragraph (SP-3 is a filled polymer); 15 % MoS2 from boedeker-sp3 (15% MoS2 Filled) and kiriuri-sp3; monomers from mfgrobots-vespel (family statement for Vespel)
  designations:
    - system: ASTM
      code: D6456-99
      note: Type 3
      source: emco-sp3
      where: At a Glance, certifications line
    - system: AMS
      code: '3644'
      note: Class 5
      source: emco-sp3
      where: At a Glance, certifications line
tags:
  environments: []
  stresses:
    - vacuum-and-outgassing
    - extreme-cold
    - extreme-heat
  applications:
    - mechanisms
properties:
  - benchmark: density
    label: Specific gravity (ASTM D792), Vespel SP-3
    value: 1.6
    unit: g/cm3
    scope: material
    conditions:
      unit_in_source: specific gravity, no unit printed
      temperature: not printed
    method: Typical value printed as specific gravity 1.60 (ASTM D792); the number is entered as g/cm3 because the same figure is the density in g/cm3
    status: ground
    source: dupont-sp3-pis
    where: Typical ISO Properties table, Other Properties block, Specific Gravity row
  - benchmark: ultimate_tensile_strength
    label: Tensile strength at 23 °C, Vespel SP-3
    value: 58.5
    unit: MPa
    scope: material
    conditions:
      temperature: 23 °C (73 °F)
      specimen: machined isostatic tensile specimens made per ASTM D1708
      unit_in_source: MPa (ksi), printed as 58.5 (8.5)
    method: Typical value, ASTM D-1708 or E8, printed in the DuPont table; the table does not say yield or break
    status: ground
    source: dupont-sp3-pis
    where: Typical ISO Properties table, Mechanical Property block, Tensile Strength row, 23 °C
  - benchmark: elongation
    label: Strain at break at 23 °C, Vespel SP-3
    value: 4
    unit: '%'
    scope: material
    conditions:
      temperature: 23 °C (73 °F)
      test: ASTM D-1708 or E8
    method: Typical value printed in the DuPont table
    status: ground
    source: dupont-sp3-pis
    where: Typical ISO Properties table, Mechanical Property block, Strain at Break row, 23 °C
  - benchmark: flexural_strength
    label: Flexural strength at 23 °C, Vespel SP-3
    value: 75.8
    unit: MPa
    scope: material
    conditions:
      temperature: 23 °C (73 °F)
      test: ASTM D-790
      unit_in_source: MPa (kpsi), printed as 75.8 (11.0)
    method: Typical value printed in the DuPont table; Kiriuri reprints the same 75.8 MPa
    status: ground
    source: dupont-sp3-pis
    where: Typical ISO Properties table, Mechanical Property block, Flexural Strength row, 23 °C
  - benchmark: flexural_strength
    label: Flexural strength at 260 °C, Vespel SP-3
    value: 39.9
    unit: MPa
    scope: material
    conditions:
      temperature: 260 °C (500 °F)
      test: ASTM D-790
      unit_in_source: MPa (kpsi), printed as 39.9 (5.8)
    method: Typical value printed in the DuPont table
    status: ground
    source: dupont-sp3-pis
    where: Typical ISO Properties table, Mechanical Property block, Flexural Strength row, 260 °C
  - benchmark: flexural_modulus
    label: Flexural modulus at 23 °C, Vespel SP-3
    value: 3275
    unit: MPa
    scope: material
    conditions:
      temperature: 23 °C (73 °F)
      test: ASTM D-790
      unit_in_source: MPa (kpsi), printed as 3275 (475)
    method: Typical value printed in the DuPont table
    status: ground
    source: dupont-sp3-pis
    where: Typical ISO Properties table, Mechanical Property block, Flexural Modulus row, 23 °C
  - benchmark: flexural_modulus
    label: Flexural modulus at 260 °C, Vespel SP-3
    value: 1862
    unit: MPa
    scope: material
    conditions:
      temperature: 260 °C (500 °F)
      test: ASTM D-790
      unit_in_source: MPa (kpsi), printed as 1862 (270)
    method: Typical value printed in the DuPont table
    status: ground
    source: dupont-sp3-pis
    where: Typical ISO Properties table, Mechanical Property block, Flexural Modulus row, 260 °C
  - benchmark: compressive_stress
    label: Compressive stress at 1 % strain, Vespel SP-3
    value: 34.5
    unit: MPa
    scope: material
    conditions:
      temperature: 23 °C (73 °F)
      test: ASTM D-695
      unit_in_source: MPa (kpsi), printed as 34.5 (5.0)
    method: Typical value printed in the DuPont table
    status: ground
    source: dupont-sp3-pis
    where: Typical ISO Properties table, Mechanical Property block, Compressive Stress at 1 % strain row
  - benchmark: compressive_stress
    label: Compressive stress at 10 % strain, Vespel SP-3
    value: 127.6
    unit: MPa
    scope: material
    conditions:
      temperature: 23 °C (73 °F)
      test: ASTM D-695
      unit_in_source: MPa (kpsi), printed as 127.6 (18.5)
    method: Typical value printed in the DuPont table
    status: ground
    source: dupont-sp3-pis
    where: Typical ISO Properties table, Mechanical Property block, Compressive Stress at 10 % strain row
  - benchmark: compressive_modulus
    label: Compressive modulus at 23 °C, Vespel SP-3
    value: 2413
    unit: MPa
    scope: material
    conditions:
      temperature: 23 °C (73 °F)
      test: ASTM D-695
      unit_in_source: MPa (kpsi), printed as 2413 (350)
    method: Typical value printed in the DuPont table
    status: ground
    source: dupont-sp3-pis
    where: Typical ISO Properties table, Mechanical Property block, Compressive Modulus row
  - benchmark: izod_impact
    label: Notched Izod impact strength at 23 °C, Vespel SP-3
    value: 21.3
    unit: J/m
    scope: material
    conditions:
      temperature: 23 °C (73 °F)
      test: ASTM D-256
      notch: notched
    method: Typical value printed in the DuPont table
    status: ground
    source: dupont-sp3-pis
    where: Typical ISO Properties table, Mechanical Property block, Izod Notched Impact Strength row
  - benchmark: izod_impact
    label: Unnotched Izod impact strength at 23 °C, Vespel SP-3
    value: 112
    unit: J/m
    scope: material
    conditions:
      temperature: 23 °C (73 °F)
      test: ASTM D-256
      notch: unnotched
    method: Typical value printed in the DuPont table
    status: ground
    source: dupont-sp3-pis
    where: Typical ISO Properties table, Mechanical Property block, Izod Unnotched Impact Strength row
  - benchmark: wear_rate
    label: Wear rate, Vespel SP-3 (unlubricated in air)
    value: 17
    value_high: 23
    bound: range
    unit: m/s x 10-10
    scope: material
    conditions:
      condition: unlubricated in air, PV 0.875 MPa·m/s (DuPont footnote ††)
      unit_in_source: m/s x 10-10
    method: Range printed in the DuPont table, Wear and Friction block
    status: ground
    source: dupont-sp3-pis
    where: Typical ISO Properties table, Wear and Friction block, Wear Rate row
  - benchmark: friction_coefficient
    label: Friction coefficient at PV 0.875 MPa·m/s, Vespel SP-3
    value: 0.25
    unit: '-'
    scope: material
    conditions:
      condition: steady state, unlubricated in air, PV 0.875 MPa·m/s (DuPont footnote **)
    method: Typical value printed in the DuPont table
    status: ground
    source: dupont-sp3-pis
    where: Typical ISO Properties table, Wear and Friction block, Friction Coefficient row, PV = 0.875 MPa·m/s
  - benchmark: friction_coefficient
    label: Friction coefficient at PV 3.5 MPa·m/s, Vespel SP-3
    value: 0.17
    unit: '-'
    scope: material
    conditions:
      condition: steady state, unlubricated in air, PV 3.5 MPa·m/s (DuPont footnote **)
    method: Typical value printed in the DuPont table
    status: ground
    source: dupont-sp3-pis
    where: Typical ISO Properties table, Wear and Friction block, Friction Coefficient row, PV = 3.5 MPa·m/s
  - benchmark: friction_coefficient
    label: Friction coefficient in vacuum, Vespel SP-3
    value: 0.03
    unit: '-'
    scope: material
    conditions:
      environment: in vacuum
      load_speed_temperature: not printed in the DuPont table
    method: Typical value printed in the DuPont table, In Vacuum row
    status: ground
    source: dupont-sp3-pis
    where: Typical ISO Properties table, Wear and Friction block, In Vacuum row
  - benchmark: cte
    label: Coefficient of linear expansion, 23 to 260 °C, Vespel SP-3
    value: 52
    unit: µm/m/°C
    scope: material
    conditions:
      temperature: 23 to 260 °C (73 to 500 °F)
      test: ASTM D-696
      unit_in_source: µm/m/°C, printed as 52 (29) in/in/°F
    method: Typical value printed in the DuPont table
    status: ground
    source: dupont-sp3-pis
    where: Typical ISO Properties table, Thermal Property block, Coefficient of Linear Expansion row
  - benchmark: thermal_conductivity
    label: Thermal conductivity at 40 °C, Vespel SP-3
    value: 0.47
    unit: W/m·°C
    scope: material
    conditions:
      temperature: 40 °C (104 °F)
      unit_in_source: W/m·°C
    method: Typical value printed in the DuPont table
    status: ground
    source: dupont-sp3-pis
    where: Typical ISO Properties table, Thermal Property block, Thermal Conductivity row
  - benchmark: deformation_under_load
    label: Deformation under 14 MPa load at 50 °C, Vespel SP-3
    value: 0.12
    unit: '%'
    scope: material
    conditions:
      load: 14 MPa
      temperature: 50 °C (122 °F)
      test: ASTM D-621
    method: Typical value printed in the DuPont table
    status: ground
    source: dupont-sp3-pis
    where: Typical ISO Properties table, Thermal Property block, Deformation Under 14 MPa Load row
  - benchmark: moisture_absorption
    label: Water absorption after 24 h at 23 °C, Vespel SP-3
    value: 0.23
    unit: '%'
    scope: material
    conditions:
      time: 24 h
      temperature: 23 °C (73 °F)
      test: ASTM D570
    method: Typical value printed in the DuPont table; Boedeker and Kiriuri reprint the same 0.23 %
    status: ground
    source: dupont-sp3-pis
    where: Typical ISO Properties table, Other Properties block, Water Absorption, 24 h row
  - benchmark: moisture_absorption
    label: Water absorption after 48 h, Vespel SP-3
    value: 0.65
    unit: '%'
    scope: material
    conditions:
      time: 48 h
      temperature: 50 °C (122 °F) as printed by DuPont
      test: ASTM D570
    method: Typical value printed in the DuPont table. Kiriuri prints the same 0.65 % at 23 °C, so the two sources disagree on the test temperature; this entry keeps the DuPont value
    status: ground
    note: Kiriuri (Japanese reprint of the DuPont sheet) prints 48 h at 23 °C; DuPont prints 50 °C. Both sources are cited.
    source: dupont-sp3-pis
    where: Typical ISO Properties table, Other Properties block, Water Absorption, 48 h row
  - benchmark: max_service_temp
    label: Maximum continuous operating temperature, Vespel SP-3
    value: 500
    unit: °F
    scope: material
    conditions:
      basis: maximum continuous operating temperature as printed by a distributor; no test condition printed
    method: Printed as 500 °F on the Emco Plastics product page; kept in °F as printed (500 °F equals 260 °C)
    status: ground
    source: emco-sp3
    where: Properties table, Max Continuous Operating Temperature row
  - benchmark: decomposition_temperature
    label: Decomposition temperature, Vespel SP-3
    value: 550
    bound: lower
    unit: °C
    scope: material
    conditions:
      basis: printed as greater than 550 °C; the material decomposes without melting
    method: Value printed in the DuPont safety data sheet, physical and chemical properties block
    status: ground
    note: Section 10 of the same SDS lists temperature above 450 °C as a condition to avoid.
    source: dupont-sp3-sds
    where: Section 9, Decomposition temperature row
corrosion:
  - environment: Humid air, 23 °C
    headline: Vespel SP-3 takes up water slowly and reaches 0.23 % in 24 hours.
    effect: Water absorption is 0.23 % after 24 h at 23 °C and 0.65 % after 48 h (DuPont, printed at 50 °C). Wikipedia says the material absorbs some atmospheric moisture, which lengthens pump-down time in a vacuum; the page gives no figure for that effect.
    rating: low
    conditions:
      test: ASTM D570
      basis: typical values; the DuPont sheet gives no equilibrium value at 50 % RH
    source: dupont-sp3-pis
    where: Typical ISO Properties table, Other Properties block, Water Absorption rows
  - environment: Contact with strong acids, strong bases or strong oxidising agents
    headline: The DuPont safety data sheet lists strong acids, strong bases and strong oxidising agents as incompatible with Vespel SP-3.
    effect: No attack rate, concentration, time or temperature is printed for any of the three groups. The sheet gives no corrosion test.
    rating: unknown
    conditions:
      basis: incompatibility list only
    source: dupont-sp3-sds
    where: Section 10, Incompatible materials row
  - environment: Elevated temperature, 260 °C
    headline: At 260 °C the flexural strength and stiffness are about half their 23 °C values.
    effect: Flexural strength falls from 75.8 MPa at 23 °C to 39.9 MPa at 260 °C, and flexural modulus from 3275 MPa to 1862 MPa (ASTM D-790, DuPont). The sheet gives no ageing time for these figures.
    rating: moderate
    conditions:
      test: ASTM D-790, typical values
      time: not printed
    source: dupont-sp3-pis
    where: Typical ISO Properties table, Mechanical Property block, Flexural Strength and Flexural Modulus rows, 23 °C and 260 °C
  - environment: Vacuum, including ultra-high vacuum
    headline: Vespel SP-3 is described as giving little outgassing in vacuum, but no TML or CVCM value was read for this grade.
    effect: Wikipedia says Vespel does not produce significant outgassing even at high temperatures and performs well in vacuum down to extremely low cryogenic temperatures. The Copeplastics page lists low outgassing as a property. Neither source gives a mass-loss number for SP-3.
    rating: low
    conditions:
      basis: qualitative statements; no ASTM E595 test read for SP-3
    source: wikipedia-vespel
    where: Uses and properties text (summary of the page)
risks:
  hazards:
    - text: 'Combustible dust: if small particles are generated during further processing, handling or by other means, they may form combustible dust concentrations in air. The signal word is Warning and no pictogram is required.'
      ghs: []
      source: dupont-sp3-sds
      where: Section 2, Product hazard category and Label content
    - text: 'Not a fire or explosion hazard: the product does not burn without an external flame. Carbon monoxide and carbon dioxide are listed as combustion products.'
      ghs: []
      source: dupont-sp3-sds
      where: Section 5, Specific hazards
    - text: Dust exposure limits printed for the dust (OSHA PEL 15 mg/m3 total dust TWA and 5 mg/m3 respirable fraction TWA; ACGIH TLV 3 mg/m3 respirable and 10 mg/m3 inhalable particulate TWA).
      ghs: []
      source: dupont-sp3-sds
      where: Section 8, Non-constituent dust exposure limits
  failure_risks:
    - mode: Thermal decomposition
      trigger: Temperature above 450 °C, or abnormally long processing time or high temperature
      consequence: The sheet says this can produce irritating and toxic fumes; traces of hydrogen cyanide and isocyanic acid, with carbon monoxide and carbon dioxide, are listed as decomposition products.
      severity: moderate
      source: dupont-sp3-sds
      where: Section 10, Conditions to avoid and Hazardous decomposition products
    - mode: Loss of stiffness at high temperature
      trigger: Service at 260 °C
      consequence: Flexural modulus is 1862 MPa at 260 °C against 3275 MPa at 23 °C (ASTM D-790, typical values).
      severity: moderate
      source: dupont-sp3-pis
      where: Typical ISO Properties table, Flexural Modulus row
  side_effects:
    - text: Machining dust and fibres from parts or shapes can build up on surfaces and form combustible dust clouds if released.
      affects: Workshop air and surfaces
      source: dupont-sp3-sds
      where: Section 6, Spill cleanup; Section 7, Handling
    - text: When overheated, the material releases traces of hydrogen cyanide and isocyanic acid, plus carbon monoxide and carbon dioxide.
      affects: People near an overheated part
      source: dupont-sp3-sds
      where: Section 10, Hazardous decomposition products
  handling:
    - text: Wet machining is the preferred method, because the liquid cools the part and reduces dust. Aqueous coolants are preferred. If parts are cleaned after dry machining, rinse with deionised water.
      source: dupont-sp3-sds
      where: Section 8, Engineering controls
    - text: Clean fines and dust with HEPA-filtered vacuum equipment. Do not use compressed air, which can generate combustible dust clouds.
      source: dupont-sp3-sds
      where: Section 6, Spill cleanup; Section 7, Handling (Personnel)
    - text: Wear leather or cotton gloves when grinding, sawing, routing, drilling or sanding.
      source: dupont-sp3-sds
      where: Section 8, Hand protection
    - text: Keep the container closed to prevent contamination, in an area equipped with sprinklers.
      source: dupont-sp3-sds
      where: Section 7, Storage
  mitigations:
    - text: Wet machining with mist collection and local exhaust ventilation or dust collection, to keep airborne dust below the exposure limits.
      source: dupont-sp3-sds
      where: Section 8, Engineering controls
uses:
  - application: mechanisms
    device: Seals and plain bearings in vacuum or dry environments
    example: DuPont specifies Vespel SP-3 parts and shapes for seals and bearings in vacuum or dry environments.
    source: dupont-sp3-pis
    where: Opening paragraph
  - application: mechanisms
    device: Gears and other wear surfaces for outer space, ultra-high vacuum or dry-gas use
    example: Wikipedia lists seals, plain bearings, gears and other wear surfaces for outer space, ultra-high vacuum or dry-gas applications for SP-3.
    source: wikipedia-vespel
    where: Uses text (summary of the page); no flight or mission is named
supply:
  - subject: Molybdenum (for the MoS2 filler)
    demand: 'USGS: the Government of China imposed export controls on molybdenum powders in February 2025, prompting the United States and other countries to seek alternative sources.'
    producers:
      - country: China
        share_percent: 37.3
        year: 2025
      - country: Chile
        share_percent: 16.2
        year: 2025
      - country: Peru
        share_percent: 15
        year: 2025
      - country: United States
        share_percent: 15.4
        year: 2025
      - country: Mexico
        share_percent: 6.5
        year: 2025
    critical_lists: []
    recycling: 'USGS: molybdenum is recycled in catalysts, ferrous scrap and superalloy scrap, and recycling may supply as much as 30 % of the apparent supply.'
    substitutes:
      - 'USGS: there is little substitution for molybdenum in its major application in steels and cast irons; the chapter does not discuss molybdenum disulfide lubricants.'
    source: usgs-mcs2026-molybdenum
    where: World Mine Production and Reserves table, 2025e column (shares calculated by Space Mushroom from the printed world total of 260,000 t, molybdenum content); Events, Trends, and Issues; Recycling; Substitutes
  - subject: Vespel SP-3 parts and shapes
    producers: []
    routes: Supplied by DuPont (Section 1 of the DuPont safety data sheet). The sheet gives recycling or incineration with energy recovery as the preferred disposal options.
    source: dupont-sp3-sds
    where: Section 1, Manufacturer/Supplier; Section 13, Waste disposal methods
documents:
  - title: DuPont Vespel SP-3 Polyimide Isostatic Shapes, Product Information Sheet
    type: datasheet
    url: https://www.dupont.com/content/dam/dupont/amer/us/en/vespel/public/documents/en/VPE-A10869-00-B0614.pdf
    year: 2026
  - title: DuPont Vespel SP-3 parts and shapes, Safety Data Sheet, version 4.1 (hosted by Boedeker Plastics)
    type: sds
    url: https://www.boedeker.com/Portals/0/Safety%20Data%20Sheets%20SDS/DuPont%20Vespel/Safety-Data-Sheet-SDS-DuPont-Vespel%20SP-3-Boedeker-Plastics-2025.pdf
    year: 2023
  - title: USGS Mineral Commodity Summaries 2026, Molybdenum
    type: report
    url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-molybdenum.pdf
    year: 2026
gaps:
  - No TML, CVCM or WVR (ASTM E595 outgassing) value for Vespel SP-3 was found. NASA/TM-2000-209897 has no Vespel entry, and the NASA outgassing database did not return an SP-3 row. A TML of 1.09 % and CVCM of 0.00 % appears on a secondary page for SP-1 flight approval; it is not SP-3 and is not used.
  - No flight, orbital or radiation result for SP-3 was found in the sources opened.
  - Maximum continuous service temperature is given only by Emco Plastics (500 °F, no test condition) and by Curbell Plastics (550, no unit printed; not used). The DuPont sheet leaves its deflection temperature at 2 MPa blank.
  - Limiting PV is printed by Curbell Plastics as 40000 with no unit; not used because no unit is printed.
  - Dielectric constant, dissipation factor, dielectric strength, volume and surface resistivity, specific heat, Poisson's ratio, oxygen index, fatigue endurance limits and equilibrium moisture at 50 % RH are blank in the DuPont sheet.
  - The DuPont sheet and Kiriuri disagree on the test temperature of the 48 h water absorption value (50 °C against 23 °C). Both are cited; the DuPont figure is kept.
  - Water absorption, friction and wear test loads, speeds and temperatures for the in-vacuum friction value are not printed.
  - Steam hydrolysis and resistance to acids and bases were mentioned by Boedeker in a search summary but were not found on the page we opened, so no such numbers are given.
  - Molybdenum critical-mineral status (USGS 2025 List of Critical Minerals and the EU critical raw materials list) was not opened, so critical_lists is empty.
  - The repeat unit drawing and molecular formula were not found on any page opened. The identity is given as a description of the polyimide monomers and the filler; the Wikipedia Polyimide page confirms PMDA and ODA for Kapton, not for Vespel.
  - Monomer supply (pyromellitic dianhydride and oxydianiline) and the producer of the polymer resin were not found in a source opened in this run; DuPont is named as supplier of the parts.
  - The date of Vespel's introduction and its product history were not found on the pages opened; the Wikipedia summary gives a 1969 patent in its references but does not link it to Vespel.
  - No source named an orbit, so the environments tag is empty.
  - Several properties use names that are not in spores/property-canon.yaml (izod_impact, compressive_stress, compressive_modulus, wear_rate, friction_coefficient, deformation_under_load, decomposition_temperature).
  - Most values come from the DuPont product information sheet, read as text from the PDF in this run. Wikipedia, Emco, Copeplastics, Boedeker, Kiriuri and mfgrobots were read through a summarising fetch, so their wording is paraphrased; they are cited only for composition, uses and the single distributor temperature.
sources:
  dupont-sp3-pis:
    title: DuPont Vespel SP-3 Polyimide Isostatic Shapes, Product Information Sheet (Typical ISO Properties)
    id: DuPont VPE-A10869-00-B0614 (printed reference A20 VPE-A40173-00-B0526)
    url: https://www.dupont.com/content/dam/dupont/amer/us/en/vespel/public/documents/en/VPE-A10869-00-B0614.pdf
    year: 2026
    kind: datasheet
    license: DuPont product information; cited, not reproduced
  dupont-sp3-sds:
    title: Safety Data Sheet, Vespel SP-3 parts and shapes, version 4.1 (DuPont, Ref. 150000003867)
    id: Issue date 09/07/2023; revision date 06/07/2021
    url: https://www.boedeker.com/Portals/0/Safety%20Data%20Sheets%20SDS/DuPont%20Vespel/Safety-Data-Sheet-SDS-DuPont-Vespel%20SP-3-Boedeker-Plastics-2025.pdf
    year: 2023
    kind: datasheet
    license: supplier safety data sheet, linked not reproduced
  boedeker-sp3:
    title: Boedeker Plastics product page, Vespel SP-3
    id: boedeker.com/Product/Vespel-SP-3
    url: https://www.boedeker.com/Product/Vespel-SP-3
    kind: web
    license: distributor page, cited
  emco-sp3:
    title: Emco Plastics product page, Vespel SP-3
    id: emcoplastics.com/vespel-sp-3
    url: https://www.emcoplastics.com/vespel-sp-3/
    kind: web
    license: distributor page, cited
  copeplastics-sp3:
    title: Cope Plastics material page, Vespel SP-3
    id: copeplastics.com/materials/vespel-sp-3
    url: https://www.copeplastics.com/materials/vespel-sp-3/
    kind: web
    license: distributor page, cited
  kiriuri-sp3:
    title: Kiriuri material data sheet, Vespel SP-3 (Japanese reprint of the DuPont product information sheet, issued 2026-08-27)
    id: Kiriuri, Material Data Sheet (butsuseihyou_vespel-sp-3)
    url: https://files.bcart.jp/kurimotokakou/uploads/zaisitusyoumeisyo/butuseihyou/grade/butsuseihyou_vespel-sp-3.pdf
    year: 2026
    kind: web
    license: reseller reprint, cited
  wikipedia-vespel:
    title: Vespel, Wikipedia
    id: en.wikipedia.org/wiki/Vespel
    url: https://en.wikipedia.org/wiki/Vespel
    kind: web
    license: CC BY-SA (Wikipedia), cited
  mfgrobots-vespel:
    title: Vespel material article, MFG Robots (monomer statement)
    id: mfgrobots.com/Article/material/resin/8298
    url: https://www.mfgrobots.com/Article/material/resin/8298.html
    kind: web
    license: web article, cited
  usgs-mcs2026-molybdenum:
    title: Mineral Commodity Summaries 2026, Molybdenum
    id: USGS MCS 2026, February 2026
    url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-molybdenum.pdf
    year: 2026
    kind: report
    license: public domain (USGS)
license: CC-BY-4.0
updated: '2026-11-01'
review:
  status: draft
  method: assistant
  checked_values: 23
  unreachable: 0
  caveats: 1
  note: Written by an AI assistant on 2026-11-01 from the DuPont product information sheet and SDS (read as PDF text), the USGS molybdenum table, and distributor and Wikipedia pages read through a summarising fetch. Not yet checked by verify-values.
story:
  recipe:
    line: Vespel SP-3 is a polyimide filled with molybdenum disulfide. The polyimide is a condensation polymer of pyromellitic dianhydride and 4,4'-oxydianiline (ODA). The grade contains 15 % MoS2 by weight as the solid lubricant.
    parts:
      - name: Pyromellitic dianhydride (PMDA)
        share: polymer monomer
        role: The dianhydride that, with ODA, forms the imide rings of the polyimide chain (Vespel is described as a condensation-type polyimide made from PMDA and ODA).
      - name: 4,4'-oxydianiline (ODA)
        share: polymer monomer
        role: The diamine that, with PMDA, makes up the polyimide repeat unit.
      - name: Molybdenum disulfide (MoS2)
        share: 15 % by weight (SP-3 grade)
        role: Solid lubricant filler that gives wear and friction resistance in vacuum and moisture-free environments.
  risk_groups:
    - title: For people
      level: 0
      verdict: Combustible dust, not a fire or explosion hazard as a…
      lead: The DuPont safety data sheet gives combustible dust as the only hazard category. The solid part does not burn without an external flame.
      points:
        - label: The solid part
          line: The sheet says the product does not burn without an external flame and is not a fire or explosion hazard. No pictogram is required, and the signal word is Warning because of dust.
        - label: Dust from machining
          line: Fine dust and fibres from machining can form combustible dust clouds in air. The sheet gives OSHA limits of 15 mg/m3 total dust and 5 mg/m3 respirable fraction, both as time-weighted averages.
        - label: In a fire
          line: Combustion products are carbon monoxide and carbon dioxide. Overheating above 450 °C can release traces of hydrogen cyanide and isocyanic acid.
    - title: If the part overheats
      lead: These are the limits printed by the manufacturer. The sheet gives no field incidents.
      points:
        - label: Decomposition
          line: The material decomposes without melting, at temperatures greater than 550 °C. The sheet lists temperatures above 450 °C as a condition to avoid.
        - label: Strength at 260 °C
          line: At 260 °C the flexural strength is 39.9 MPa and the flexural modulus is 1862 MPa, against 75.8 MPa and 3275 MPa at 23 °C (ASTM D-790, DuPont typical values).
    - title: Handling and storage
      points:
        - label: Machining
          line: Wet machining is preferred, with aqueous coolant and mist collection. Clean dust with a HEPA-filtered vacuum, not with compressed air.
        - label: Storage
          line: Keep the container closed and store the material in an area equipped with sprinklers.
  why: Vespel SP-3 is a polyimide shape with 15 % molybdenum disulfide added to give low friction and wear without oil or grease. DuPont specifies it for seals and bearings in vacuum or dry environments, and the typical friction coefficient in vacuum is 0.03 against 0.25 in air at PV 0.875 MPa·m/s. It is chosen where a lubricant would evaporate, outgas or be unusable, and the trade-off is strength that falls by about half at 260 °C.
  uses:
    - where: Vacuum and dry-running bearings and seals
      line: DuPont states that Vespel SP-3 parts and shapes are specified for seals and bearings in vacuum or dry environments.
    - where: Gears and wear surfaces for space and vacuum use
      line: Wikipedia lists seals, plain bearings, gears and other wear surfaces for outer space, ultra-high vacuum or dry-gas applications for SP-3. The page names no mission or flight.
  can_do:
    - label: Friction in vacuum
      benchmark: friction_coefficient
      value: '0.03'
      line: In vacuum the friction coefficient is printed as 0.03 (DuPont typical value). The load, speed and temperature for that test are not printed.
    - label: Strength at 23 °C
      benchmark: ultimate_tensile_strength
      value: 58.5 MPa
      line: Tensile strength at 23 °C is 58.5 MPa with a strain at break of 4.0 % (ASTM D-1708 or E8, DuPont typical values).
    - label: Stiffness at 260 °C
      benchmark: flexural_modulus
      value: 1862 MPa
      line: Flexural modulus at 260 °C is 1862 MPa, against 3275 MPa at 23 °C (ASTM D-790, DuPont typical values).
    - label: Service temperature
      benchmark: max_service_temp
      value: 500 °F
      line: The distributor Emco Plastics prints a maximum continuous operating temperature of 500 °F with no test condition.
  compare: Vespel SP-3 is a dry-running polymer rather than a metal or oil-based lubricant, and its advantage is friction in vacuum, not strength. Its typical friction coefficient is 0.03 in vacuum and 0.25 in air at PV 0.875 MPa·m/s, against a flexural modulus of 3275 MPa at 23 °C that falls to 1862 MPa at 260 °C. The table compares its density, flexural modulus and service temperature.
  compare_rows:
    - label: Specific gravity
      benchmark: density
    - label: Flexural modulus at 23 °C
      benchmark: flexural_modulus
    - label: Maximum continuous service temperature
      benchmark: max_service_temp
  handling:
    - The solid part is not classified as a fire or explosion hazard, but machining dust can form combustible clouds. Use wet machining and HEPA vacuum cleaning.
    - Wear leather or cotton gloves when grinding, sawing, routing, drilling or sanding.
    - Keep the container closed and avoid overheating above 450 °C, which can release irritating and toxic fumes.
  good_for:
    - Dry-running bearings and seals in vacuum. The DuPont typical friction coefficient in vacuum is 0.03.
    - Parts that must not outgas a lubricant. Wikipedia says the grade does not produce significant outgassing, though no mass-loss number was found for SP-3.
  watch_out:
    - Strength at high temperature. The flexural modulus is 1862 MPa at 260 °C, against 3275 MPa at 23 °C.
    - Water absorption of 0.23 % in 24 h at 23 °C, which can add pump-down time in vacuum.
    - Combustible dust from machining. Use wet cutting and HEPA cleaning.
  verdict: Vespel SP-3 is a dry-running polymer for vacuum bearings and seals. It gives a low friction coefficient in vacuum, and its strength and stiffness drop by about half at 260 °C in DuPont's typical values.