spore: profile
id: vespel-sp1
spore_version: 0.2
family: polyimides
name: Vespel SP-1 (DuPont unfilled polyimide)
abbreviation: Vespel SP-1
role: machined high-temperature polymer part, unfilled base grade
category: polymers
type: polyimides
summary: |
  Vespel SP-1 is DuPont's unfilled polyimide resin, sold as direct-formed parts and as machined shapes. The DuPont direct-formed sheet gives a tensile strength of 72.4 MPa at 23 °C, and a copy of DuPont's datasheet rates the material to 260 °C in air. Its weak points are moisture uptake of 1 to 1.3 % at equilibrium and creep, which the DuPont direct-formed sheet puts at 0.2 % deformation under 14 MPa at 50 °C.
best_for: Machined insulating parts that must hold strength at high temperature in dry air or vacuum, where moisture uptake and creep are acceptable
weakest_at: Moisture uptake of 1 to 1.3 % at 50 % RH equilibrium, and creep (0.2 % deformation under 14 MPa at 50 °C for direct-formed parts)
identity:
  formula: Unfilled polyimide resin (DuPont Vespel SP-1); the repeat-unit structure is not printed on any source read
  designations:
    - system: Trade name
      code: Vespel® SP-1
      source: dupont-df
      where: Title of the DuPont product information sheet
  source: schmidt-bartl
  where: 'Material Data Sheet, header: Chem. Designation Polyimide, DIN abbreviation PI'
tags:
  environments: []
  stresses: []
  applications:
    - mechanisms
    - heat-shields
properties:
  - benchmark: ultimate_tensile_strength
    label: Tensile strength, direct-formed parts, 23 °C
    value: 72.4
    unit: MPa
    scope: material
    conditions:
      form: direct-formed (DF) parts and shapes
      temperature: 23 °C (73 °F)
      standard: ASTM D-1708 or E8 (DF specimens per E-8 figure 19, tested by D638)
      orientation: perpendicular to the forming direction
    method: Typical value printed in the DuPont direct-formed table; the sheet describes its values as typical, not guaranteed
    status: ground
    source: dupont-df
    where: Typical Direct-Formed Properties table, Tensile Strength row, 23 °C
  - benchmark: ultimate_tensile_strength
    label: Tensile strength, direct-formed parts, 260 °C
    value: 36.5
    unit: MPa
    scope: material
    conditions:
      form: direct-formed (DF) parts and shapes
      temperature: 260 °C (500 °F)
      standard: ASTM D-1708 or E8
      orientation: perpendicular to the forming direction
    method: Typical value in the DuPont direct-formed table
    status: ground
    source: dupont-df
    where: Typical Direct-Formed Properties table, Tensile Strength row, 260 °C
  - benchmark: elongation
    label: Strain at break, direct-formed parts, 23 °C
    value: 7.5
    unit: '%'
    scope: material
    conditions:
      form: direct-formed (DF) parts and shapes
      temperature: 23 °C (73 °F)
      standard: ASTM D-1708 or E8
    method: Typical value in the DuPont direct-formed table
    status: ground
    source: dupont-df
    where: Typical Direct-Formed Properties table, Strain at Break row, 23 °C
  - benchmark: flexural_strength
    label: Flexural strength, direct-formed parts, 23 °C
    value: 82.7
    unit: MPa
    scope: material
    conditions:
      form: direct-formed (DF) parts and shapes
      temperature: 23 °C (73 °F)
      standard: ASTM D-790
    method: Typical value in the DuPont direct-formed table
    status: ground
    source: dupont-df
    where: Typical Direct-Formed Properties table, Flexural Strength row, 23 °C
  - benchmark: flexural_modulus
    label: Flexural modulus, direct-formed parts, 23 °C
    value: 2482
    unit: MPa
    scope: material
    conditions:
      form: direct-formed (DF) parts and shapes
      temperature: 23 °C (73 °F)
      standard: ASTM D-790
    method: Typical value in the DuPont direct-formed table
    status: ground
    source: dupont-df
    where: Typical Direct-Formed Properties table, Flexural Modulus row, 23 °C
  - benchmark: cte
    label: Coefficient of thermal expansion, direct-formed parts, 23 to 260 °C
    value: 50
    unit: µm/m/°C
    scope: material
    conditions:
      form: direct-formed (DF) parts and shapes
      temperature_range: 23 to 260 °C (73 to 500 °F)
      standard: ASTM D-696
      printed_also: 28 in/in/°F
    method: Typical value in the DuPont direct-formed table
    status: ground
    source: dupont-df
    where: Typical Direct-Formed Properties table, Coefficient of Linear Expansion row
  - benchmark: thermal_conductivity
    label: Thermal conductivity, direct-formed parts, 40 °C
    value: 0.29
    unit: W/m·°C
    scope: material
    conditions:
      form: direct-formed (DF) parts and shapes
      temperature: 40 °C (104 °F)
      orientation: measured parallel to the forming direction (asterisked in the sheet)
    method: Value marked with an asterisk in the DuPont direct-formed table; the sheet gives no test standard
    status: ground
    source: dupont-df
    where: Typical Direct-Formed Properties table, Thermal Conductivity row
  - benchmark: density
    label: Specific gravity, direct-formed parts
    value: 1.34
    unit: '-'
    scope: material
    conditions:
      form: direct-formed (DF) parts and shapes
      note: specific gravity is dimensionless; the sheet prints no unit
    method: Typical value in the DuPont direct-formed table, ASTM D792
    status: ground
    note: The BearingWorks copy of the DuPont datasheet gives 1.43 g/cc for the same grade without naming the form. The two values differ, so use the form that matches your part.
    source: dupont-df
    where: Typical Direct-Formed Properties table, Other Properties, Specific Gravity row
  - benchmark: deformation_under_load
    label: Deformation under a 14 MPa load at 50 °C, direct-formed parts
    value: 0.2
    unit: '%'
    scope: material
    conditions:
      form: direct-formed (DF) parts and shapes
      load: 14 MPa
      temperature: 50 °C (122 °F)
      standard: ASTM D-621
    method: Typical value in the DuPont direct-formed table
    status: ground
    note: Creep-type name is not in the property canon; see gaps.
    source: dupont-df
    where: Typical Direct-Formed Properties table, Deformation Under 14 MPa Load row
  - benchmark: decomposition_temperature
    label: Decomposition temperature, SP-1 parts and shapes
    value: 550
    bound: lower
    unit: °C
    scope: material
    conditions:
      form: SP-1 parts and shapes (supplier SDS, product grade list covers direct-formed parts and shapes)
      basis: printed as '>550 °C'
    method: Physical and chemical properties section of the DuPont SDS; no test standard printed
    status: ground
    note: The SDS says the material decomposes without melting. Its conditions to avoid start at 450 °C (see risks).
    source: dupont-sds
    where: Section 9, Decomposition temperature
  - benchmark: density
    label: Density, BearingWorks copy of DuPont datasheet
    value: 1.43
    unit: g/cc
    scope: material
    conditions:
      form: not stated on the copy
      standard: ASTM D792
    method: Specific gravity row of the Physical Properties table in the BearingWorks copy
    status: ground
    source: bearingworks-sp1
    where: Physical Properties table, Specific Gravity row
  - benchmark: ultimate_tensile_strength
    label: Tensile strength, BearingWorks copy, 23 °C
    value: 86.2
    unit: MPa
    scope: material
    conditions:
      form: not stated on the copy
      temperature: 23 °C (73 °F)
      standard: ASTM D1708
    method: Mechanical Properties table in the BearingWorks copy of the DuPont datasheet
    status: ground
    note: Differs from the 72.4 MPa direct-formed value above. The copy does not name the form, so both values are kept side by side.
    source: bearingworks-sp1
    where: Mechanical Properties table, Tensile Strength, Ultimate, 73 °F row
  - benchmark: flexural_modulus
    label: Flexural modulus, BearingWorks copy, 23 °C
    value: 3.1
    unit: GPa
    scope: material
    conditions:
      form: not stated on the copy
      temperature: 23 °C (73 °F)
      standard: ASTM D790
    method: Mechanical Properties table in the BearingWorks copy
    status: ground
    note: Differs from the 2482 MPa direct-formed value above (2.48 GPa); form not named on the copy.
    source: bearingworks-sp1
    where: Mechanical Properties table, Flexural Modulus, 73 °F row
  - benchmark: moisture_absorption
    label: Moisture absorption at equilibrium, 50 % RH
    value: 1
    value_high: 1.3
    bound: range
    unit: '%'
    scope: material
    conditions:
      state: equilibrium
      relative_humidity: 50 % RH
      form: not stated on the copy
    method: Range printed in the Physical Properties table of the BearingWorks copy; no test standard printed
    status: ground
    source: bearingworks-sp1
    where: Physical Properties table, Moisture Absorption at Equilibrium row
  - benchmark: heat_deflection_temperature
    label: Deflection temperature under 1.8 MPa load
    value: 360
    unit: °C
    scope: material
    conditions:
      load: 1.8 MPa (264 psi)
      form: not stated on the copy
      standard: ASTM D648
    method: Other Properties table in the BearingWorks copy, printed as 'Approximate'
    status: ground
    source: bearingworks-sp1
    where: Thermal Properties table, Deflection Temperature at 1.8 MPa row
  - benchmark: max_service_temp
    label: Maximum service temperature in air
    value: 260
    unit: °C
    scope: material
    conditions:
      atmosphere: air
      note: printed as 500 °F with 'w/trips to 900 °F'
    method: Thermal Properties table in the BearingWorks copy; the sheet does not state a duration
    status: ground
    note: The Schmidt + Bartl sheet gives 240 °C for continuous service, so the two sheets disagree. Both are kept.
    source: bearingworks-sp1
    where: Thermal Properties table, Maximum Service Temperature, Air row
  - benchmark: dielectric_strength
    label: Dielectric strength, short time, 80 mil thick
    value: 22
    unit: kV/mm
    scope: material
    conditions:
      test: short time
      thickness: 80 mil thick, as printed
      temperature: 23 °C (73 °F)
      standard: ASTM D149
    method: Electrical Properties table in the BearingWorks copy; printed as 560 V/mil
    status: ground
    note: Schmidt + Bartl gives 28 kV/mm for dry material (ISO/IEC 60243), so the two sheets disagree.
    source: bearingworks-sp1
    where: Electrical Properties table, Dielectric Strength row
  - benchmark: dielectric_constant
    label: Dielectric constant at 100 Hz
    value: 3.62
    unit: '-'
    scope: material
    conditions:
      frequency: 100 Hz (printed as 10^2 Hz)
      temperature: 23 °C (73 °F)
      standard: ASTM D150
    method: Electrical Properties table in the BearingWorks copy
    status: ground
    source: bearingworks-sp1
    where: Electrical Properties table, Dielectric Constant rows (102 Hz)
  - benchmark: dissipation_factor
    label: Dissipation factor at 100 Hz
    value: 0.0018
    unit: '-'
    scope: material
    conditions:
      frequency: 100 Hz (printed as 10^2 Hz)
      temperature: 23 °C (73 °F)
      standard: ASTM D150
    method: Electrical Properties table in the BearingWorks copy
    status: ground
    source: bearingworks-sp1
    where: Electrical Properties table, Dissipation Factor rows (102 Hz)
  - benchmark: oxygen_index
    label: Limiting oxygen index
    value: 53
    unit: '%'
    scope: material
    conditions:
      standard: ASTM D2863
      type: limiting oxygen index
    method: Thermal Properties table of the BearingWorks copy, printed as 'Limiting'
    status: ground
    note: Name is not in the property canon; see gaps.
    source: bearingworks-sp1
    where: Thermal Properties table, last row (Oxygen Index)
  - benchmark: specific_heat
    label: Specific heat capacity
    value: 1.13
    unit: J/g-°C
    scope: material
    conditions:
      temperature: not stated on the copy
    method: Thermal Properties table in the BearingWorks copy
    status: ground
    source: bearingworks-sp1
    where: Thermal Properties table, Specific Heat Capacity row
  - benchmark: thermal_conductivity
    label: Thermal conductivity, BearingWorks copy, 40 °C
    value: 0.346
    unit: W/m-K
    scope: material
    conditions:
      temperature: 40 °C (104 °F)
      form: not stated on the copy
    method: Thermal Properties table in the BearingWorks copy
    status: ground
    note: Direct-formed value is 0.29 W/m·°C at 40 °C; the copy does not name the form.
    source: bearingworks-sp1
    where: Thermal Properties table, Thermal Conductivity row
  - benchmark: cte
    label: Coefficient of thermal expansion, BearingWorks copy, 73 to 572 °F
    value: 54
    unit: µm/m-°C
    scope: material
    conditions:
      temperature_range: 73 to 572 °F (23 to 300 °C)
      standard: ASTM E-228
      form: not stated on the copy
    method: Thermal Properties table in the BearingWorks copy
    status: ground
    note: The same copy also prints 45 µm/m-°C for -80 to 73 °F.
    source: bearingworks-sp1
    where: Thermal Properties table, CTE, linear row, 73-572 °F
  - benchmark: moisture_absorption
    label: Water absorption at saturation in water, 23 °C
    value: 2.5
    unit: '%'
    scope: material
    conditions:
      state: saturation in water
      temperature: 23 °C
    method: Schmidt + Bartl table, Water absorption, at saturation in water of 23 °C row
    status: ground
    source: schmidt-bartl
    where: Properties table, Water absorption rows (saturation in water of 23 °C)
  - benchmark: cte
    label: Coefficient of thermal expansion, 23 to 100 °C
    value: 45
    unit: 10^-6 m/(m·K)
    scope: material
    conditions:
      temperature_range: 23 to 100 °C
      note: Schmidt + Bartl also prints 50 for 23 to 150 °C and 55 above 150 °C
    method: Average value printed in the Schmidt + Bartl Thermal Properties table
    status: ground
    source: schmidt-bartl
    where: Thermal Properties table, CTE average between 23 and 100 °C row
  - benchmark: elastic_modulus
    label: Modulus of elasticity in tension, dry, 23 °C
    value: 2200
    unit: MPa
    scope: material
    conditions:
      state: dry
      temperature: 23 °C
      standard: ISO 527-1/-2
    method: Mechanical Properties table in the Schmidt + Bartl sheet
    status: ground
    source: schmidt-bartl
    where: Mechanical Properties table, Modulus of elasticity in tension row
  - benchmark: max_service_temp
    label: Continuous service temperature in air, long term
    value: 240
    unit: °C
    scope: material
    conditions:
      atmosphere: air
      duration: minimum 5000 h and 20000 h (the sheet prints both in one column)
    method: Thermal Properties table in the Schmidt + Bartl sheet
    status: ground
    note: Disagrees with the 260 °C maximum service temperature in the BearingWorks copy of the DuPont sheet. The durations are not separated in the printed table.
    source: schmidt-bartl
    where: Thermal Properties table, Max. service temperature in air, continuously row
  - benchmark: max_service_temp
    label: Short-period service temperature in air
    value: 450
    unit: °C
    scope: material
    conditions:
      atmosphere: air
      duration: a few hours
      load: no or very low load
    method: Thermal Properties table in the Schmidt + Bartl sheet; footnote 2 limits this to short exposures
    status: ground
    source: schmidt-bartl
    where: Thermal Properties table, Max. service temperature in air, short periods row; footnote 2
  - benchmark: dielectric_strength
    label: Dielectric strength, dry, Schmidt + Bartl
    value: 28
    unit: kV/mm
    scope: material
    conditions:
      state: dry
      standard: ISO/IEC 60243
    method: Electrical Properties table in the Schmidt + Bartl sheet
    status: ground
    note: Differs from the 22 kV/mm (ASTM D149, 80 mil) in the BearingWorks copy.
    source: schmidt-bartl
    where: Electrical Properties table, Dielectric strength row
corrosion:
  - environment: Humid air at 50 % RH (equilibrium moisture)
    headline: Vespel SP-1 takes up about 1 to 1.3 % moisture at equilibrium at 50 % RH.
    effect: The BearingWorks copy of the DuPont datasheet prints 1 to 1.3 % moisture absorption at equilibrium at 50 % RH. Wikipedia says the material absorbs a small amount of atmospheric moisture, which lengthens the time needed to pump down a vacuum chamber. Schmidt + Bartl gives 2.5 % at saturation in water at 23 °C. No dimensional change or property loss for moisture is printed.
    rating: low
    conditions:
      state: equilibrium at 50 % RH
      temperature: 23 °C (73 °F)
      note: rating is a judgement from the moisture figure; no source gives a property loss
    source: bearingworks-sp1
    where: Physical Properties table, Moisture Absorption at Equilibrium row; Wikipedia, Characteristics and applications section
  - environment: Heat ageing in air
    headline: 'The two datasheets give different continuous service limits in air: 260 °C and 240 °C.'
    effect: The BearingWorks copy gives a maximum service temperature in air of 260 °C. Schmidt + Bartl gives 240 °C continuous for 5000 h and 20000 h, and 450 °C for short periods. Wikipedia gives an operating range from cryogenic temperatures to 300 °C for SP-1 and says it withstands repeated heating to 300 °C, a statement the page marks as needing a citation. No ageing rate or retained-property figure is printed by any source read.
    rating: unknown
    conditions:
      atmosphere: air
      duration: 5000 h and 20000 h in the Schmidt + Bartl sheet; not stated for the other values
    source: schmidt-bartl
    where: Thermal Properties table; footnote 2
  - environment: Strong acids, strong bases and strong oxidizing agents
    headline: The DuPont SDS lists strong acids, strong bases and strong oxidizers as incompatible. No corrosion rate is printed.
    effect: Section 10 of the DuPont SDS lists strong acids, strong bases and strong oxidizing agents as incompatible materials. The sheet gives no test, rate or exposure time for any of them.
    rating: unknown
    conditions:
      basis: incompatibility list only
    source: dupont-sds
    where: Section 10, Incompatible materials
  - environment: Vacuum and high temperature (outgassing)
    headline: Wikipedia says Vespel does not produce significant outgassing even at high temperature.
    effect: Wikipedia says Vespel does not produce significant outgassing even at high temperatures, which makes it useful for lightweight heat shields and crucible support, and that it performs well in vacuum down to very low cryogenic temperatures. The page gives no outgassing numbers. An ASTM E 595 result for this grade was not read; see gaps.
    rating: low
    conditions:
      basis: qualitative statement on Wikipedia, no test values
    source: wiki-vespel
    where: Characteristics and applications section
risks:
  hazards:
    - text: DuPont SDS for Vespel SP-1 parts and shapes (version 4.1, issue date 09/06/2023) classifies the product hazard as combustible dust, with the signal word Warning and no pictogram required. The hazard applies when small particles are made by machining or other handling.
      ghs: []
      source: dupont-sds
      where: Section 2, Hazards identification
    - text: The SDS says the product is not a fire or explosion hazard and does not burn without an external flame. It is insoluble in water and decomposes without melting.
      ghs: []
      source: dupont-sds
      where: Sections 5 and 9
    - text: The SDS says the product contains no ingredients that need disclosure under OSHA HazCom 2012, and it gives no toxicological data for the product itself.
      ghs: []
      source: dupont-sds
      where: Sections 3 and 11
  failure_risks:
    - mode: Creep under sustained load
      trigger: A 14 MPa load at 50 °C (ASTM D-621), for direct-formed parts
      consequence: Deformation of 0.2 % in the DuPont direct-formed table. The BearingWorks copy prints 0.14 % at 2000 psi and 122 °F (ASTM D621).
      source: dupont-df
      where: Typical Direct-Formed Properties table, Deformation Under 14 MPa Load row
    - mode: Thermal decomposition above 450 °C
      trigger: Temperature above 450 °C, or abnormally long processing time at high temperature
      consequence: The SDS says the process produces irritating and toxic fumes. Hazardous thermal decomposition products may include traces of hydrogen cyanide and isocyanic acid, plus carbon monoxide and carbon dioxide.
      source: dupont-sds
      where: Section 10, Conditions to avoid and Hazardous decomposition products
    - mode: Moisture uptake lengthens vacuum pump-down
      trigger: Exposure to atmospheric moisture before vacuum use
      consequence: Longer pump time while in vacuum, according to Wikipedia. No time or pressure figure is given.
      source: wiki-vespel
      where: Characteristics and applications section
  side_effects:
    - text: Machining produces fine dust and fibres. The SDS advises wet machining, because the liquid cools the part and reduces dust. Aqueous coolants are preferred.
      affects: Operators and workshop air
      source: dupont-sds
      where: Section 8, Engineering controls
  handling:
    - text: Use wet machining where possible. Clean fines with a HEPA-filtered vacuum, and do not use compressed air, which can raise combustible dust clouds.
      source: dupont-sds
      where: Sections 6, 7 and 8
    - text: Avoid breathing dust or fibres. The SDS advises leather or cotton gloves when grinding, sawing, routing, drilling or sanding.
      source: dupont-sds
      where: Sections 7 and 8, Hand protection
    - text: Direct-formed parts have lower performance than parts machined from compression-molded or isostatic shapes, according to Wikipedia. Choose the shape that matches the load.
      source: wiki-vespel
      where: Processing for manufacturing applications and Types sections
  mitigations:
    - text: For dry vacuum sliding parts, Wikipedia names the MoS2-filled SP-3 grade, because graphite-filled grades become abrasive where moisture is absent.
      source: wiki-vespel
      where: Types section, SP-3 entry
uses:
  - application: mechanisms
    device: Axle bushing in a shape-memory-alloy rotating arm (prototype; the paper describes a flight actuator design but gives no flight record)
    example: The prototype axle runs in a bushing of MoS2-impregnated polyimide (SP-3 Vespel from DuPont). The paper reports operation verified at Mars temperature and pressure from -50 to 0 °C. This is the SP-3 grade, not the unfilled SP-1 grade in this profile.
    source: jenkins-landis
    where: Description of the actuator (axle bushing paragraph); test summary near the end
  - application: heat-shields
    device: Lightweight heat shields and crucible support
    example: Wikipedia says Vespel is used for lightweight heat shields and crucible support because it does not produce significant outgassing even at high temperatures. The page does not give a grade or a test for this use.
    source: wiki-vespel
    where: Characteristics and applications section
supply:
  - subject: Vespel SP-1 (DuPont polyimide parts)
    abundance: 'Not found in any source we hold: no producer country, production share or production volume for Vespel was printed.'
    producers: []
    critical_lists: []
    substitutes: []
    source: dupont-vespel-page
    where: 'DuPont product page, Vespel Polyimide Parts and Shapes section: parts are available in standard and custom-machined forms, supported by DuPont. The page names no production site. The Wikipedia Vespel lead (wiki-vespel) says the plastics are made by DuPont.'
  - subject: Polyimide monomers, general chemistry
    abundance: Not found in any source we hold for Vespel monomers or feedstock volume. The monomers below are the classic polyimide example, Kapton, not a confirmed Vespel formula.
    producers: []
    critical_lists: []
    substitutes: []
    source: wiki-polyimide
    where: 'Introduction: ''A classic polyimide is Kapton, which is produced by condensation of pyromellitic dianhydride and 4,4''-oxydianiline.'' Synthesis section names other dianhydrides and diamines. The page names no producers or manufacturing countries.'
  - subject: Pyromellitic dianhydride (PMDA), polyimide precursor
    abundance: Not found in any source we hold for PMDA producers or production volume.
    producers: []
    critical_lists: []
    substitutes: []
    source: wiki-pmda
    where: 'Lead: PMDA is ''the double carboxylic acid anhydride that is used in the preparation of polyimide polymers such as Kapton''. Preparation section: the industrial route is gas-phase oxidation of 1,2,4,5-tetramethylbenzene. The page names no producers or production countries.'
media: []
documents:
  - title: DuPont Vespel SP-1 Polyimide Direct-Formed Parts, product information sheet (reference A20 VPE-A40171-00-B0526)
    type: datasheet
    url: https://www.dupont.com/content/dam/dupont/amer/us/en/vespel/public/documents/en/VPE-A10860-00-B0614.pdf
  - title: DuPont Vespel SP-1 parts and shapes, safety data sheet version 4.1 (issue date 09/06/2023), distributed 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-1-Boedeker-Plastics-2025.pdf?ver=fdi-Y3NLXtjbD8kFABL0iw%3D%3D
  - title: Dupont Vespel SP-1 Polyimide Unfilled, physical properties, metric and English (copy hosted by BearingWorks)
    type: datasheet
    url: https://www.bearingworks.com/uploaded-assets/pdfs/retainers/vespel-sp1-datasheet.pdf
  - title: Schmidt + Bartl GmbH, Material Data Sheet Vespel SP1
    type: datasheet
    url: https://www.schmidt-bartl.de/pdfs_en/halbzeuge/technischedatenblaetter/PI_Vespel__SP1_en.pdf
  - title: 'NASA NTRS 19950020856: A Rotating Arm Using Shape-Memory Alloy (Jenkins and Landis)'
    type: report
    url: https://ntrs.nasa.gov/api/citations/19950020856/downloads/19950020856.pdf
  - title: 'Wikipedia: Vespel'
    type: database
    url: https://en.wikipedia.org/wiki/Vespel
gaps:
  - No atomic-oxygen erosion yield for Vespel SP-1 was read. A search snippet mentioned a Vespel yield in a LEO study, but that paper was not opened.
  - No ASTM E 595 total mass loss or CVCM value for SP-1 was read from a primary record. The NASA outgassing database was not reached, and a reseller white paper that quotes it was blocked by a bot check.
  - No radiation (proton, electron, UV), total ionising dose or vacuum thermal-cycling result for SP-1 was found.
  - No cryogenic mechanical data below -50 °C for SP-1 was found. Wikipedia gives cryogenic use with no number.
  - No moisture-absorption, creep or property data for the SP-3 MoS2 grade are in this profile. The SP-3 bushing use is kept because it is the only flight-related Vespel use found, and it is labelled as a different grade.
  - 'Supply: no producer country shares, production volume, abundance or critical-mineral listing for Vespel was found. DuPont is named as the maker (Wikipedia Vespel page, DuPont product page), with no grade-level data. The feedstock entries are for polyimide in general (Kapton is the example the Wikipedia page gives), not a confirmed Vespel monomer list.'
  - 'Atomic-oxygen search: not run in this pass, because the web search allowance for this run was used up. The NASA outgassing database page loaded its search interface but showed no Vespel record in the read.'
  - 'Chemical resistance: only the SDS incompatibility list was read. No compatibility rating or exposure data for named chemicals was found. A Professional Plastics guide that lists steam, ammonia and amine limits was blocked, so it was not used.'
  - The sheets do not agree and do not all name the form (direct-formed, isostatic or compression-molded). The BearingWorks copy and the Schmidt + Bartl sheet name no form. Values are kept side by side with their source. Wikipedia says its table is for isostatic material.
  - Dielectric constant and dissipation factor for direct-formed parts were not read reliably because the layout of the DuPont direct-formed table was garbled. Only the BearingWorks copy values are used.
  - 'Property names not in spores/property-canon.yaml: deformation_under_load, decomposition_temperature and oxygen_index.'
  - Hazard data rest on the DuPont SDS (through a distributor) only. No PubChem or GHS record for Vespel was read, and no CAS number was read.
  - Repeat-unit chemistry (monomers and molar mass) is not printed on any source read, so the recipe lists the grade and the forming routes only.
  - Volume resistivity is printed in the BearingWorks copy as 1e+016 - 1e+017 ohm-cm (ASTM D257, 73 °F). It is left out of the numeric record because the value check cannot match a three-digit exponent in that print.
  - 'Count: 29 properties and 9 sources. The gap is mainly atomic oxygen, outgassing and cryogenic data, which the sources read did not contain.'
sources:
  dupont-df:
    title: DuPont Vespel SP-1 Polyimide Direct-Formed Parts, product information sheet
    id: DuPont reference A20 VPE-A40171-00-B0526
    url: https://www.dupont.com/content/dam/dupont/amer/us/en/vespel/public/documents/en/VPE-A10860-00-B0614.pdf
    kind: datasheet
    license: manufacturer document, linked not reproduced
  bearingworks-sp1:
    title: Dupont Vespel SP-1 Polyimide Unfilled, physical properties (metric and English), copy hosted by BearingWorks
    id: copy of the DuPont SP-1 unfilled datasheet
    url: https://www.bearingworks.com/uploaded-assets/pdfs/retainers/vespel-sp1-datasheet.pdf
    kind: datasheet
    license: reseller copy of a manufacturer document, linked not reproduced
  schmidt-bartl:
    title: Schmidt + Bartl GmbH, Material Data Sheet Vespel SP1
    id: Schmidt + Bartl GmbH, Villingen-Schwenningen
    url: https://www.schmidt-bartl.de/pdfs_en/halbzeuge/technischedatenblaetter/PI_Vespel__SP1_en.pdf
    kind: datasheet
    license: supplier document, linked not reproduced
  dupont-sds:
    title: DuPont Vespel SP-1 parts and shapes, safety data sheet version 4.1
    id: DuPont reference 150000003758; issue date 09/06/2023; distributed by Boedeker Plastics
    url: https://www.boedeker.com/Portals/0/Safety%20Data%20Sheets%20SDS/DuPont%20Vespel/Safety-Data-Sheet-SDS-DuPont-Vespel%20SP-1-Boedeker-Plastics-2025.pdf?ver=fdi-Y3NLXtjbD8kFABL0iw%3D%3D
    kind: datasheet
    license: manufacturer SDS, linked not reproduced
  jenkins-landis:
    title: A Rotating Arm Using Shape-Memory Alloy (Phillip P. Jenkins and Geoffrey A. Landis, NASA)
    id: NASA NTRS 19950020856
    url: https://ntrs.nasa.gov/api/citations/19950020856/downloads/19950020856.pdf
    kind: report
    license: NASA NTRS document, linked not reproduced
  wiki-vespel:
    title: Wikipedia, Vespel
    url: https://en.wikipedia.org/wiki/Vespel
    kind: web
    license: CC BY-SA (Wikipedia)
    note: Used for description, processing routes, grade descriptions and the qualitative outgassing and vacuum statements. Not used for numeric property values.
  wiki-polyimide:
    title: Wikipedia, Polyimide
    url: https://en.wikipedia.org/wiki/Polyimide
    kind: web
    license: CC BY-SA (Wikipedia)
    note: Used for the general polyimide chemistry (the Kapton monomers as the classic example) and the producer check. It does not name Vespel monomers or any Vespel producer.
  wiki-pmda:
    title: Wikipedia, Pyromellitic dianhydride
    url: https://en.wikipedia.org/wiki/Pyromellitic_dianhydride
    kind: web
    license: CC BY-SA (Wikipedia)
    note: Used for the role of PMDA as a polyimide precursor and its industrial preparation route. It names no producers or production countries.
  dupont-vespel-page:
    title: DuPont, Vespel polyimide parts and shapes product page
    url: https://www.dupont.com/products/vespel.html
    kind: web
    license: manufacturer web page, linked not reproduced
    note: Used for the statement that DuPont supplies Vespel parts in standard and custom-machined forms. The page names no production site and no grade list.
license: CC-BY-4.0
updated: '2026-11-02'
review:
  status: draft
  method: assistant
  checked_values: 29
  unreachable: 3
  caveats: 4
  note: Written by an AI assistant on 2026-11-01 from the DuPont direct-formed sheet, the DuPont SDS, a BearingWorks copy of the DuPont datasheet, the Schmidt + Bartl datasheet, a NASA paper and Wikipedia. Two Curbell Plastics PDFs were blocked by a bot check and a Professional Plastics guide returned an HTML page, so they were not used.
story:
  recipe:
    line: Vespel SP-1 is an unfilled polyimide resin. DuPont's product sheet calls it an unfilled polymer, and the grade is the base resin of the Vespel SP family. Shapes are made by compression molding (plates and rings), isostatic molding (rods and tubes) or direct forming (small parts in volume), according to Wikipedia.
    parts:
      - name: Polyimide resin (unfilled)
        symbol: PI
        role: The whole material. SP-1 is the unfilled base resin. The other SP grades add graphite, PTFE or molybdenum disulfide.
        share_note: unfilled, no filler (DuPont product sheet)
        source: dupont-df
        where: Title and first paragraph
  risk_groups:
    - title: For people
      level: 1
      verdict: Combustible dust when machined
      lead: The supplier safety data sheet classifies the product only as a combustible dust hazard, once it is ground or machined into fine particles.
      points:
        - label: The part
          line: The DuPont SDS gives the signal word Warning and no pictogram. It says the product is not a fire or explosion hazard and does not burn without an external flame.
        - label: Dust
          line: Fine dust from machining can form a combustible dust cloud in air. Use wet machining and a HEPA-filtered vacuum. Do not clean with compressed air.
        - label: Data
          line: The SDS gives no toxicological data for the product itself and no ingredient that needs disclosure.
    - title: In service
      lead: These values come from datasheets and an NASA prototype, not from failures of flight hardware.
      points:
        - label: Load and heat
          line: Direct-formed parts deform 0.2 % under a 14 MPa load at 50 °C. Above 450 °C the SDS warns of irritating and toxic decomposition fumes.
        - label: Moisture
          line: The BearingWorks copy gives 1 to 1.3 % moisture at equilibrium at 50 % RH. Wikipedia says this lengthens the pump-down of a vacuum chamber.
    - title: Handling and storage
      points:
        - label: Shape
          line: Direct-formed parts perform below parts machined from compression-molded or isostatic shapes, so choose the shape that matches the load.
        - label: Storage
          line: The SDS advises keeping containers closed and in an area with sprinklers.
  why: Vespel SP-1 is DuPont's unfilled polyimide resin, sold as shapes and direct-formed parts for high-temperature insulating and wear uses. A copy of the DuPont datasheet rates it to 260 °C in air. The sources read disagree on several values, so each number below is shown with its source and its test form. The unfilled base grade is the reference for the other Vespel grades.
  uses:
    - where: Spacecraft mechanism bushing (prototype)
      line: A NASA paper describes an axle bushing of MoS2-impregnated polyimide in a shape-memory-alloy rotating arm. It was tested at Mars temperature and pressure from -50 to 0 °C. The bushing is the SP-3 grade, not this unfilled SP-1 grade.
    - where: Lightweight heat shields and crucible support
      line: Wikipedia says the material is used for lightweight heat shields and crucible support, because it does not produce significant outgassing even at high temperatures.
  can_do:
    - label: Strength
      benchmark: ultimate_tensile_strength
      value: 72.4 MPa at 23 °C, direct-formed parts
      line: Direct-formed SP-1 parts have a tensile strength of 72.4 MPa at 23 °C, according to the DuPont direct-formed sheet. A copy of the DuPont datasheet prints 86.2 MPa at 73 °F (23 °C) for a form it does not name.
    - label: Heat
      benchmark: max_service_temp
      value: 260 °C in air
      line: A copy of the DuPont datasheet gives a maximum service temperature of 260 °C in air. Schmidt + Bartl gives 240 °C for continuous service over 5000 h and 20000 h, and 450 °C for short periods.
    - label: Expansion
      benchmark: cte
      value: 50 µm/m/°C, 23 to 260 °C
      line: The DuPont direct-formed sheet gives a linear coefficient of thermal expansion of 50 µm/m/°C from 23 to 260 °C, under ASTM D-696.
  compare: Within the Vespel family, SP-1 is the unfilled base resin. Its strength depends on the form. The DuPont direct-formed sheet gives a tensile strength of 72.4 MPa at 23 °C, and the BearingWorks copy gives 86.2 MPa at 23 °C for a form it does not name. Use the figure for the form that matches your part.
  compare_rows:
    - label: Tensile strength at 23 °C
      benchmark: ultimate_tensile_strength
    - label: Maximum service temperature in air
      benchmark: max_service_temp
    - label: Density (specific gravity)
      benchmark: density
  handling:
    - Use wet machining where possible. Clean fines with a HEPA-filtered vacuum, not compressed air.
    - Keep containers closed and avoid breathing dust or fibres.
    - Keep the material away from strong acids, strong bases and strong oxidizing agents, as the SDS lists them as incompatible.
  good_for:
    - Electrical insulation at high temperature. The BearingWorks copy gives 22 kV/mm dielectric strength for 80 mil thick material under ASTM D149.
    - Machined parts for dry air and vacuum, where outgassing is low according to Wikipedia.
  watch_out:
    - Moisture uptake of 1 to 1.3 % at 50 % RH equilibrium, which lengthens vacuum pump-down.
    - Creep. Direct-formed parts deform 0.2 % under a 14 MPa load at 50 °C.
    - Machining dust is combustible. The SDS names it as the main hazard.
    - 'The two datasheets disagree on the continuous service limit: 260 °C and 240 °C.'
  verdict: Vespel SP-1 is an insulating polyimide for machined parts that must hold strength at high temperature. The sources read give 260 °C maximum service temperature in air and 72.4 MPa tensile strength for direct-formed parts, but they disagree on several values. No atomic-oxygen, radiation or outgassing number for SP-1 was found, so the profile does not rate it for space exposure.