Polyamide-imide PAI

spore: profile
id: pai-torlon
spore_version: 0.2
family: high-performance-polymers
name: Polyamide-imide
abbreviation: PAI
role: high-performance thermoplastic (Torlon), unfilled tough grade 4203L and graphite-filled bearing grade 4301
category: polymers
type: high-performance
summary: |
  Polyamide-imide (PAI, sold as Torlon by Solvay, now part of the Syensqo group) is an amorphous, high-temperature thermoplastic. Torlon 4203L is the unfilled, toughest grade; Torlon 4301 is a graphite-filled bearing grade. Drake's extruded 4203L sheet gives a glass transition of 275 °C and a heat deflection temperature of 278 °C at 264 psi. The Syensqo 4301 sheet gives a tensile strength of 113 MPa and a heat deflection temperature of 279 °C at 1.8 MPa. The design guide reports that 4203L keeps 67 % of its tensile strength after 17,000 hours at 250 °C. No atomic-oxygen erosion value for PAI was found.
best_for: Wear-resistant bearing parts and electrical insulators that must keep their strength near 250 °C
weakest_at: Water uptake, attack by saturated steam and strong bases, and no atomic-oxygen or outgassing data found
identity:
  formula: 'Polyamide-imide: amide and imide links on an aromatic chain, made from trimellitic anhydride with methylene dianiline (MDA) or with methylenediphenyl diisocyanate (MDI)'
  source: wiki-pai
  where: Wikipedia Polyamide-imide article, Production section (acid chloride route with TMAC and MDA; diisocyanate route with MDI and TMA). The page prints no CAS number and no repeat-unit formula.
  designations:
    - system: ASTM
      code: PAI000R03A56316E11FB41
      note: ASTM D5204 classification, Torlon 4203L
      source: torlon-design-guide
      where: ASTM D5204 cross reference table, p. 34
    - system: ASTM
      code: PAI000L15A32232E12FB42
      note: ASTM D5204 classification, Torlon 4301
      source: torlon-design-guide
      where: ASTM D5204 cross reference table, p. 34
    - system: AMS
      code: '3670'
      note: Specification for Torlon PAI materials
      source: torlon-design-guide
      where: SAE-Aerospace Material Specifications paragraph, p. 34
    - system: Trade name
      code: Torlon 4203L
      source: drake-4203
      where: Title block, TORLON 4203L and 4203 PAI
    - system: Trade name
      code: '4301'
      note: Torlon 4301 grade number
      source: syensqo-4301
      where: Title block, Torlon 4301 polyamide-imide
tags:
  environments: []
  stresses:
    - uv
    - extreme-heat
  applications:
    - mechanisms
    - electronics-and-chips
    - thermal-control
properties:
  - benchmark: density
    label: Density, Torlon 4203 extruded shape
    value: 1.41
    unit: g/cc
    scope: material
    conditions:
      grade: Torlon 4203L extruded shape
      test: ASTM D792
    method: Specific gravity printed on the Drake extruded-shape sheet
    status: ground
    source: drake-4203
    where: Extruded shapes properties, Physical, Specific Gravity row
  - benchmark: density
    label: Density, Torlon 4301
    value: 1.45
    unit: g/cm3
    scope: material
    conditions:
      grade: Torlon 4301
      test: ASTM D792 (typical value in the legacy table)
    method: Typical value in the legacy Torlon table. The Syensqo 4301 sheet prints 1.46 with no unit, so that value is not used.
    status: ground
    source: wshampshire-torlon
    where: TYPICAL PROPERTIES table, PHYSICAL, Density row, Torlon 4301 column
  - benchmark: ultimate_tensile_strength
    label: Tensile strength, Torlon 4203L extruded shape
    value: 138
    unit: MPa
    scope: material
    conditions:
      grade: Torlon 4203L extruded shape, machined specimen
      test: ASTM D638
    method: Drake states that extruded-shape values come from machined specimens and can differ from resin-maker values
    status: ground
    source: drake-4203
    where: Extruded shapes properties, Mechanical, Tensile Strength Ultimate row
  - benchmark: elongation
    label: Elongation at break, Torlon 4203L extruded shape
    value: 20
    unit: '%'
    scope: material
    conditions:
      grade: Torlon 4203L extruded shape
      test: ASTM D638
    method: Value printed on the Drake extruded-shape sheet
    status: ground
    source: drake-4203
    where: Extruded shapes properties, Mechanical, Elongation at Break row
  - benchmark: elastic_modulus
    label: Tensile modulus, Torlon 4203L extruded shape
    value: 4136
    unit: MPa
    scope: material
    conditions:
      grade: Torlon 4203L extruded shape
      test: ASTM D638
    method: Value printed on the Drake extruded-shape sheet (600,000 psi also printed)
    status: ground
    source: drake-4203
    where: Extruded shapes properties, Mechanical, Tensile Modulus row
  - benchmark: flexural_modulus
    label: Flexural modulus, Torlon 4203L extruded shape
    value: 4136
    unit: MPa
    scope: material
    conditions:
      grade: Torlon 4203L extruded shape
      test: ASTM D790
    method: Value printed on the Drake extruded-shape sheet
    status: ground
    source: drake-4203
    where: Extruded shapes properties, Mechanical, Flexural Modulus row
  - benchmark: flexural_strength
    label: Flexural yield strength, Torlon 4203L extruded shape
    value: 165
    unit: MPa
    scope: material
    conditions:
      grade: Torlon 4203L extruded shape
      test: ASTM D790
      basis: yield
    method: Value printed on the Drake extruded-shape sheet
    status: ground
    source: drake-4203
    where: Extruded shapes properties, Mechanical, Flexural Yield Strength row
  - benchmark: glass_transition_temperature
    label: Glass transition temperature, Torlon 4203L extruded shape
    value: 275
    unit: °C
    scope: material
    conditions:
      grade: Torlon 4203L extruded shape
      test: ASTM D3418
    method: Value printed on the Drake extruded-shape sheet (527 °F also printed)
    status: ground
    source: drake-4203
    where: Extruded shapes properties, Thermal, Glass Transition Temp./Tg row
  - benchmark: heat_deflection_temperature
    label: Heat deflection temperature, Torlon 4203L extruded shape
    value: 278
    unit: °C
    scope: material
    conditions:
      grade: Torlon 4203L extruded shape
      load: 264 psi
      test: ASTM TMA
    method: Value printed on the Drake extruded-shape sheet
    status: ground
    source: drake-4203
    where: Extruded shapes properties, Thermal, Heat Deflection Temperature (264 PSI) row
  - benchmark: cte
    label: Coefficient of linear thermal expansion, Torlon 4203L extruded shape
    value: 0.000031
    unit: 1/°C
    scope: material
    conditions:
      grade: Torlon 4203L extruded shape
      test: E831 TMA
      printed: 3.1 x 10-5 C-1
    method: Value printed on the Drake extruded-shape sheet, converted from 3.1 x 10-5 per degC to the decimal form
    status: ground
    source: drake-4203
    where: Extruded shapes properties, Thermal, Coefficient of Linear Thermal Expansion row
  - benchmark: izod_impact
    label: Notched Izod impact strength, Torlon 4203L extruded shape
    value: 105
    unit: J/m
    scope: material
    conditions:
      grade: Torlon 4203L extruded shape
      test: ASTM D256 Type A
      notch: notched
    method: Value printed on the Drake extruded-shape sheet. The name izod_impact is not in the property canon.
    status: ground
    source: drake-4203
    where: Extruded shapes properties, Mechanical, Izod Impact (notched) row
  - benchmark: moisture_absorption
    label: Water absorption, Torlon 4203L extruded shape, 24 h immersion
    value: 0.4
    unit: '%'
    scope: material
    conditions:
      grade: Torlon 4203L extruded shape
      test: ASTM D570
      exposure: immersion, 24 h
    method: Value printed on the Drake extruded-shape sheet
    status: ground
    source: drake-4203
    where: Extruded shapes properties, Physical, Water Absorption row
  - benchmark: moisture_absorption
    label: Water absorption at saturation, Torlon 4203L extruded shape
    value: 1.7
    unit: '%'
    scope: material
    conditions:
      grade: Torlon 4203L extruded shape
      test: ASTM D570
      exposure: immersion to saturation
    method: Value printed on the Drake extruded-shape sheet
    status: ground
    source: drake-4203
    where: Extruded shapes properties, Physical, Water Absorption at Saturation row
  - benchmark: dielectric_constant
    label: Dielectric constant, Torlon 4203 electrical grade
    value: 4.2
    unit: '-'
    scope: material
    conditions:
      grade: Torlon 4203
      test: ASTM D150
      frequency: 1 MHz
    method: Typical value in the legacy Torlon table (undated reseller copy)
    status: ground
    source: wshampshire-torlon
    where: TYPICAL PROPERTIES table, ELECTRICAL, Dielectric Constant at 1 MHz row, Torlon 4203 column
  - benchmark: dielectric_strength
    label: Dielectric strength, Torlon 4203 electrical grade, short time
    value: 580
    unit: V/mil
    scope: material
    conditions:
      grade: Torlon 4203
      test: ASTM D149
      thickness: 1/8 inch, short time
    method: Typical value in the legacy Torlon table (undated reseller copy); printed in V/mil
    status: ground
    source: wshampshire-torlon
    where: TYPICAL PROPERTIES table, ELECTRICAL, Dielectric Strength row, Torlon 4203 column
  - benchmark: max_service_temp
    label: Maximum operating temperature, Torlon 4203
    value: 260
    unit: °C
    scope: material
    conditions:
      grade: Torlon 4203
      basis: continuous use, as printed 500 °F / 260 °C
    method: Value in the legacy Torlon table; the text says continuous temperatures to 500 °F (260 °C)
    status: ground
    source: wshampshire-torlon
    where: TYPICAL PROPERTIES table, THERMAL, Max Operating Temp row; grade description
  - benchmark: ultimate_tensile_strength
    label: Tensile strength, Torlon 4301 injection-moulded
    value: 113
    unit: MPa
    scope: material
    conditions:
      grade: Torlon 4301
      test: ASTM D638
    method: Typical value printed on the Syensqo 4301 sheet (ASTM D1708 gives 163 MPa, which the sheet says is for history only)
    status: ground
    source: syensqo-4301
    where: Page 2, Mechanical, Tensile Strength row
  - benchmark: elongation
    label: Elongation at break, Torlon 4301
    value: 3.3
    unit: '%'
    scope: material
    conditions:
      grade: Torlon 4301
      test: ASTM D638
    method: Typical value printed on the Syensqo 4301 sheet
    status: ground
    source: syensqo-4301
    where: Page 2, Mechanical, Tensile Elongation Break row
  - benchmark: elastic_modulus
    label: Tensile modulus, Torlon 4301
    value: 6830
    unit: MPa
    scope: material
    conditions:
      grade: Torlon 4301
      test: ASTM D638
    method: Typical value printed on the Syensqo 4301 sheet
    status: ground
    source: syensqo-4301
    where: Page 2, Mechanical, Tensile Modulus first row
  - benchmark: flexural_strength
    label: Flexural strength, Torlon 4301 at 23 °C
    value: 215
    unit: MPa
    scope: material
    conditions:
      grade: Torlon 4301
      test: ASTM D790
      temperature: 23 °C
    method: Typical value printed on the Syensqo 4301 sheet
    status: ground
    source: syensqo-4301
    where: Page 2, Mechanical, Flexural Strength 23°C row
  - benchmark: flexural_strength
    label: Flexural strength, Torlon 4301 at 232 °C
    value: 112
    unit: MPa
    scope: material
    conditions:
      grade: Torlon 4301
      test: ASTM D790
      temperature: 232 °C
    method: Typical value printed on the Syensqo 4301 sheet; shows the strength kept at high temperature
    status: ground
    source: syensqo-4301
    where: Page 2, Mechanical, Flexural Strength 232°C row
  - benchmark: flexural_modulus
    label: Flexural modulus, Torlon 4301 at 23 °C
    value: 6890
    unit: MPa
    scope: material
    conditions:
      grade: Torlon 4301
      test: ASTM D790
      temperature: 23 °C
    method: Typical value printed on the Syensqo 4301 sheet
    status: ground
    source: syensqo-4301
    where: Page 2, Mechanical, Flexural Modulus 23°C row
  - benchmark: compressive_strength
    label: Compressive strength, Torlon 4301
    value: 166
    unit: MPa
    scope: material
    conditions:
      grade: Torlon 4301
      test: ASTM D695
    method: Typical value printed on the Syensqo 4301 sheet. The name compressive_strength is not in the property canon.
    status: ground
    source: syensqo-4301
    where: Page 2, Mechanical, Compressive Strength row
  - benchmark: izod_impact
    label: Notched Izod impact strength, Torlon 4301
    value: 64
    unit: J/m
    scope: material
    conditions:
      grade: Torlon 4301
      test: ASTM D256
      notch: notched
    method: Typical value printed on the Syensqo 4301 sheet
    status: ground
    source: syensqo-4301
    where: Page 2, Impact, Notched Izod Impact row
  - benchmark: heat_deflection_temperature
    label: Heat deflection temperature, Torlon 4301, unannealed
    value: 279
    unit: °C
    scope: material
    conditions:
      grade: Torlon 4301, unannealed
      test: ASTM D648
      load: 1.8 MPa
    method: Typical value printed on the Syensqo 4301 sheet
    status: ground
    source: syensqo-4301
    where: Page 2, Thermal, Deflection Temperature Under Load 1.8 MPa Unannealed row
  - benchmark: thermal_conductivity
    label: Thermal conductivity, Torlon 4301
    value: 0.53
    unit: W/m/K
    scope: material
    conditions:
      grade: Torlon 4301
      test: ASTM C177
    method: Typical value printed on the Syensqo 4301 sheet
    status: ground
    source: syensqo-4301
    where: Page 2, Thermal, Thermal Conductivity row
  - benchmark: cte
    label: Coefficient of linear thermal expansion, Torlon 4301
    value: 0.000025
    unit: cm/cm/°C
    scope: material
    conditions:
      grade: Torlon 4301
      test: ASTM D696
      printed: 2.5E-5 cm/cm/°C
    method: Value printed on the Syensqo 4301 sheet, written in decimal form
    status: ground
    source: syensqo-4301
    where: Page 2, Thermal, Coefficient of Linear Thermal Expansion row
  - benchmark: moisture_absorption
    label: Water absorption, Torlon 4301, 24 h
    value: 0.28
    unit: '%'
    scope: material
    conditions:
      grade: Torlon 4301
      test: ASTM D570
      exposure: 24 h
    method: Typical value printed on the Syensqo 4301 sheet
    status: ground
    source: syensqo-4301
    where: Page 2, Physical, Water Absorption (24 hr) row
corrosion:
  - environment: Aircraft hydraulic fluid (Skydrol 500B), 1,000 h
    headline: Torlon 4301 kept 89.6 % of its tensile strength after 1,000 h in Skydrol at 135 °C.
    effect: Immersion for 1,000 h at 135 °C left 89.6 % of the tensile strength of Torlon 4301 and kept 94.1 % of its elongation. At -80 °C for 1,000 h it kept 94.0 % of tensile strength. The design guide says the loss at 135 °C is not embrittlement, because elongation was kept.
    rating: low
    conditions:
      fluid: Skydrol 500B
      time: 1,000 hours
      temperature: 135 °C and -80 °C
      grade: Torlon 4301
    source: torlon-design-guide
    where: Table 26, p. 23, and the text on automotive and aviation fluids
  - environment: Motor oil, transmission fluid and gear lube at 149 °C
    headline: Torlon 4203L kept its flexural strength in automotive lubricants at 149 °C.
    effect: After one month at 149 °C, 4203L kept 99.4 % (motor oil), 100.3 % (transmission fluid) and 102.7 % (gear lube) of its flexural strength, with no weight change.
    rating: none
    conditions:
      time: one month
      temperature: 149 °C (300 °F)
      grade: Torlon 4203L
    source: torlon-design-guide
    where: Table 24, p. 23
  - environment: Saturated steam, strong bases and some high-temperature acids
    headline: The design guide says PAI may be attacked by saturated steam and strong bases.
    effect: Torlon PAI is virtually unaffected by hydrocarbons, chlorinated and fluorinated hydrocarbons and most acids at moderate temperatures. It may be attacked by saturated steam, strong bases and some high-temperature acid systems. Proper post-cure is needed for the best chemical resistance. No time, concentration or retention figure is printed for these agents.
    rating: moderate
    conditions:
      agents: saturated steam, strong bases, high-temperature acid systems
      stress: not stated
    source: torlon-design-guide
    where: Chemical Resistance text, p. 21
  - environment: Mixed chemicals, 24 h at 93 °C (Torlon 4203L)
    headline: Most solvents and common acids are rated excellent; formic acid (88 %), furfural and some amines are fair or poor.
    effect: In the 24 h test at 93 °C, 4203L was rated A (no attack) for acetic acid, hydrochloric acid (10 % and 37 %), chromic acid (10 %), acetonitrile, chloroform and methyl ethyl ketone, among others. It was rated C (fair) for formic acid (88 %) and furfural, and F (poor) for benzene sulfonic acid, ethylene diamine, pyridine and 2-aminoethanol.
    rating: moderate
    conditions:
      time: 24 hours
      temperature: 93 °C (200 °F)
      grade: Torlon 4203L
    source: torlon-design-guide
    where: 'Table 23, p. 21 (key: A excellent, B good, C fair, F poor)'
  - environment: Humidity and water immersion
    headline: PAI parts take up water slowly and recover their size and properties when dried.
    effect: Absorbed water changes dimensions a little and lowers strength. At 2 % absorbed water, 4203L lost 7 % of its tensile strength and 11 % of its tensile modulus. Original dimensions were restored by 16 h at 149 °C (300 °F) for the design guide test panels. Absorbed water also limits how fast a wet part can be heated.
    rating: low
    conditions:
      exposure: water absorption to 2 % by weight, and 23 °C and 50 % RH panels
      grade: Torlon 4203L
    source: torlon-design-guide
    where: Table 27, p. 25; Dimensional changes and Restoration text, p. 24
  - environment: Heat ageing at 250 °C (Torlon 4203L, 3.2 mm bars)
    headline: Tensile strength falls to 67 % of its initial value after 17,000 h at 250 °C.
    effect: Tensile strength retained was 110 % at 2,000 h, 86 % at 12,000 h and 67 % at 17,000 h. Notched Izod retained 101 %, 67 % and 38 %. Dimensional change was 0.0 %, 0.5 % and 0.9 %, and the UL 94 rating stayed V-0. The design guide notes that tensile strength first rises above the standard post-cure value.
    rating: moderate
    conditions:
      temperature: 250 °C (482 °F)
      specimen: 3.2 mm bars, ASTM D1708 tensile
      grade: Torlon 4203L
    source: torlon-design-guide
    where: Table 11, p. 15; text on thermal ageing, p. 14
  - environment: Simulated sunlight and weathering (Weather-O-meter, 6,000 h)
    headline: Torlon 4203L did not degrade after 6,000 h of Weather-O-meter exposure.
    effect: The design guide says 6,000 h is roughly five years of outdoor exposure. The bearing grade 4301 contains graphite powder that makes it black and screens UV, so it is more resistant still. No tensile retention number is printed in the text read.
    rating: low
    conditions:
      test: Atlas carbon arc Weather-O-meter, black panel 63 °C, 50 % RH, 18 min spray every 102 min
      time: 6,000 hours
    source: torlon-design-guide
    where: Weather-O-meter Testing text, p. 26
  - environment: Gamma radiation
    headline: About 5 % loss of tensile strength at the highest gamma dose shown.
    effect: The design guide says gamma radiation has a negligible effect on Torlon PAI, with only about 5 % loss in tensile strength at the highest dose plotted in Figure 39. The dose exponent is lost in the PDF text, so no dose value is recorded here.
    rating: low
    conditions:
      dose: highest dose in Figure 39, value not transcribed
    source: torlon-design-guide
    where: Resistance to Gamma Radiation text, p. 26
risks:
  hazards:
    - text: 'Trimellitic anhydride, the main PAI monomer: PubChem''s aggregated ECHA notifications list H317 (may cause an allergic skin reaction), H318 (causes serious eye damage), H334 (may cause allergy or asthma symptoms or breathing difficulties if inhaled) and H335 (may cause respiratory irritation). Some notifications add H370 and H372 (damage to organs).'
      ghs:
        - H317
        - H318
        - H334
        - H335
      source: pubchem-tma
      where: GHS Classification, aggregated ECHA C&L notifications (CID 11089)
    - text: No safety data sheet for Torlon PAI resin was read in this run. Syensqo says SDS are available by emailing it or its sales representative.
      ghs: []
      source: syensqo-4301
      where: Page 3 of 3, disclaimer
  failure_risks:
    - mode: Loss of strength after long heat exposure
      trigger: Continuous exposure at 250 °C (482 °F)
      consequence: 4203L kept 86 % of its tensile strength after 12,000 h and 67 % after 17,000 h. The design guide says it still suits demanding applications after extended exposure to 250 °C.
      severity: moderate
      source: torlon-design-guide
      where: Table 11, p. 15
    - mode: Thermal shock of a wet part
      trigger: Sudden exposure to high temperature while the part holds absorbed water
      consequence: Absorbed water limits the rate at which a part can be heated. The design guide gives thermal-shock temperature against moisture content (Figures 35 and 36).
      severity: moderate
      source: torlon-design-guide
      where: Constraints on sudden high-temperature exposure, p. 25
    - mode: Attack by saturated steam or strong bases
      trigger: Saturated steam at high temperature, or strong bases
      consequence: The polymer may be attacked. The design guide says proper post-cure is needed for the best chemical resistance.
      severity: high
      source: torlon-design-guide
      where: Chemical Resistance text, p. 21
    - mode: Strength loss in hydraulic fluid at 135 °C
      trigger: 1,000 h immersion in Skydrol 500B at 135 °C
      consequence: Tensile strength fell about 10 % for Torlon 4301 and 4275, but elongation held, so the loss is not embrittlement.
      severity: low
      source: torlon-design-guide
      where: Text on automotive and aviation fluids, p. 23
  side_effects:
    - text: Not found in the sources read for PAI in service or in a fire. The monomer trimellitic anhydride is listed as a sensitiser (see hazards), but no gas or smoke composition for PAI was found.
      affects: Not found
      source: pubchem-tma
      where: GHS Classification (CID 11089)
  handling:
    - text: 'Dry the resin before moulding: at least 3 h at 177 °C (350 °F), or 4 h at 149 °C (300 °F), or 16 h at 121 °C (250 °F). The suggested maximum moisture is 0.050 %.'
      source: syensqo-4301
      where: Page 3, Injection table and Injection notes
    - text: Post-cure moulded parts. The Syensqo sheet says moulded parts must be post cured; the design guide says proper post-cure is needed for chemical resistance.
      source: syensqo-4301
      where: Page 3, Notes
    - text: Dry wet parts to restore dimensions and properties. The design guide used 16 h at 149 °C (300 °F) for its test panels.
      source: torlon-design-guide
      where: Restoration of dimensions text, p. 24
    - text: Read the supplier SDS before handling the monomer trimellitic anhydride, which PubChem lists as a sensitiser.
      source: pubchem-tma
      where: GHS Classification (CID 11089)
  mitigations:
    - text: Use the graphite-filled 4301 grade where UV or outdoor exposure matters; the design guide says the bearing grades screen UV and resist outdoor exposure even better than 4203L.
      source: torlon-design-guide
      where: Weather-O-meter Testing text, p. 26
    - text: Post-cure and dry parts before service, so they reach the chemical resistance and dimensions in the design guide.
      source: torlon-design-guide
      where: Chemical Resistance text, p. 21; Restoration text, p. 24
uses:
  - application: mechanisms
    device: Thrust washers, spline liners, valve seats, bushings, bearings, wear rings and cams (Torlon 4301)
    example: Syensqo lists these as potential applications of Torlon 4301, which combines strength at high temperature with wear resistance.
    source: syensqo-4301
    where: Page 1, description and applications
  - application: thermal-control
    device: Thermal insulators and isolators (Torlon 4203L)
    example: Drake lists thermal insulators and isolators among the typical applications of 4203L and calls it the best thermal insulator of the Torlon grades.
    source: drake-4203
    where: Description and typical applications, p. 1
  - application: electronics-and-chips
    device: Electrical connectors and insulators (Torlon 4203)
    example: A reseller sheet says 4203 is commonly used for electrical connectors and insulators because of its high dielectric strength.
    source: wshampshire-torlon
    where: Torlon 4203 (Electrical Grade) description
  - application: electronics-and-chips
    device: Aerospace electrical components needing high strength, heat resistance and V-0 flammability (Torlon 4203L)
    example: Drake lists these as a typical application of 4203L.
    source: drake-4203
    where: Typical applications, p. 1
  - application: electronics-and-chips
    device: Magnet wire enamel, often applied over polyester enamel for a higher thermal rating
    example: Wikipedia names magnet wire enamel as the major use of PAI.
    source: wiki-pai
    where: Uses section
supply:
  - subject: Trimellitic anhydride (main PAI monomer)
    abundance: Several thousand tons are produced annually (Wikipedia, no year printed)
    producers: []
    critical_lists: []
    recycling: Not found
    substitutes: []
    source: wiki-tma
    where: Production and Uses sections
  - subject: 1,2,4-Trimethylbenzene (feedstock for trimellitic anhydride)
    abundance: Not found
    producers: []
    critical_lists: []
    recycling: Not found
    substitutes: []
    source: wiki-tma
    where: 'Production section: trimellitic anhydride is produced by air oxidation of 1,2,4-trimethylbenzene'
  - subject: Torlon PAI resin
    abundance: Not found
    producers: []
    critical_lists: []
    recycling: Not found
    substitutes: []
    source: wiki-pai
    where: 'Introduction: Solvay Specialty Polymers distributes polyamide-imides under the Torlon trademark; the Syensqo group now owns the brand (datasheets)'
media: []
documents:
  - title: Torlon 4301 technical data sheet (Solvay Specialty Polymers, Syensqo group), revised 11/18/2014
    type: datasheet
    url: https://drakeplastics.com/wp-content/uploads/2025/05/Torlon-4301-PAI.pdf
    year: 2014
  - title: Torlon 4203L and 4203 PAI extruded shapes datasheet (Drake Plastics, 5.13.25)
    type: datasheet
    url: https://cn.drakeplastics.com/wp-content/uploads/2025/07/Torlon-4203_4203L-PAI_5.13.25-Datasheet.pdf
    year: 2025
  - title: Torlon PAI Design Guide (Solvay, EN 227547)
    type: datasheet
    url: https://drakeplastics.com/wp-content/uploads/2020/01/Torlon-PAI-Design-Guide_EN-227547.pdf
    year: 2020
  - title: 'PubChem: Trimellitic anhydride (CID 11089), GHS classification'
    type: database
    url: https://pubchem.ncbi.nlm.nih.gov/rest/pug_view/data/compound/11089/JSON
    year: 2026
gaps:
  - 'Atomic oxygen erosion for PAI: not found. The search returned only polyimide data, so no erosion yield is recorded for Torlon.'
  - 'Outgassing (TML, CVCM) and thermal-vacuum results for PAI: not found. The only NASA result is the non-vacuum pass under NHB 8060.1 for 4203L and 4301 (design guide, p. 34).'
  - 'Gamma dose: the design guide plots it, and the dose exponent is lost in the PDF text, so only the about 5 % loss is recorded.'
  - 'Radiation and UV retention as a number: the UV text says no degradation after 6,000 h but prints no retention value.'
  - 'Torlon 4203 (unfilled) datasheet: the 4203L Drake sheet and the design guide cover 4203L. Drake states that 4203L resin was historically sold as 4203, so the 4203 properties are treated as the same resin family.'
  - 'Tensile values differ by source and form: 113 MPa for 4301 (Syensqo, moulded), 12,000 psi for 4301 (legacy table) and 138 MPa for 4203L extruded shape (Drake, machined). Each is kept with its own conditions and is not mixed.'
  - Density of 4301 from the Syensqo sheet (1.46) has no unit printed and is not used. The 1.45 value from the legacy table is used instead.
  - Chemical ratings in Table 23 are for 4203L only; 4301 is not in that table.
  - 'Producers, country shares and year for PAI resin and for trimellitic anhydride: not found in a source read in this run.'
  - 'Critical-mineral lists for trimethylbenzene and trimellitic anhydride: not checked.'
  - 'Recycling of PAI: not found.'
  - 'Side effects of PAI in service or in a fire (gas and smoke composition): not found.'
  - 'Hazards for the PAI polymer itself: no SDS was read. Hazards come from the monomer''s PubChem summary only.'
  - Volume resistivity of 4301 (8.0E+15 ohm·cm, Syensqo sheet, p. 3) was removed because the printed exponent format did not match the verifier.
  - Property names izod_impact and compressive_strength are not in spores/property-canon.yaml, so snake_case names are used.
  - 'Media: no openly licensed PAI or Torlon image was checked, so none is included.'
  - The legacy reseller table and the Drake 4203 sheet are undated or differ from the resin-maker data; reseller values are used only where no manufacturer value was found.
sources:
  syensqo-4301:
    title: Torlon 4301 polyamide-imide technical data sheet (Solvay Specialty Polymers, a member of the Syensqo group)
    id: Revised 11/18/2014; copy hosted by Drake Plastics
    url: https://drakeplastics.com/wp-content/uploads/2025/05/Torlon-4301-PAI.pdf
    year: 2014
    kind: datasheet
    license: Manufacturer datasheet; all rights reserved by Syensqo
  drake-4203:
    title: TORLON 4203L and 4203 PAI, unreinforced, high impact resistance (Drake Plastics extruded shapes datasheet)
    id: Datasheet dated 5.13.25
    url: https://cn.drakeplastics.com/wp-content/uploads/2025/07/Torlon-4203_4203L-PAI_5.13.25-Datasheet.pdf
    year: 2025
    kind: datasheet
    license: Distributor datasheet
  torlon-design-guide:
    title: Torlon PAI Design Guide (Solvay Specialty Polymers)
    id: EN 227547; edition year not printed in the copy read; hosted by Drake Plastics
    url: https://drakeplastics.com/wp-content/uploads/2020/01/Torlon-PAI-Design-Guide_EN-227547.pdf
    year: 2020
    kind: datasheet
    license: Manufacturer design guide
  wshampshire-torlon:
    title: 'Torlon properties: typical values for Torlon 4203, 4301 and 5530 (legacy Solvay table)'
    id: Undated reseller copy
    url: https://www.wshampshire.com/wp-content/uploads/torlon_properties.pdf
    year: 2026
    kind: web
    license: Reseller property sheet; undated
  wiki-pai:
    title: Polyamide-imide (Wikipedia)
    id: Wikipedia, Polyamide-imide article (Introduction, Production, Uses)
    url: https://en.wikipedia.org/wiki/Polyamide-imide
    year: 2026
    kind: web
    license: CC-BY-SA-4.0
  wiki-tma:
    title: Trimellitic anhydride (Wikipedia)
    id: Wikipedia, Trimellitic anhydride article (Production, Uses)
    url: https://en.wikipedia.org/wiki/Trimellitic_anhydride
    year: 2026
    kind: web
    license: CC-BY-SA-4.0
  pubchem-tma:
    title: Trimellitic anhydride, PubChem CID 11089 (GHS classification, aggregated ECHA notifications)
    id: PubChem CID 11089, CAS 552-30-7
    url: https://pubchem.ncbi.nlm.nih.gov/rest/pug_view/data/compound/11089/JSON
    year: 2026
    kind: database
    license: PubChem public database
license: CC-BY-4.0
updated: '2026-10-26'
review:
  status: draft
  method: assistant
  checked_values: 28
  unreachable: 1
  caveats: 4
  note: Written by an AI assistant on 2026-10-26 from datasheets and design guide read in this run (curl and pdftotext for the PDFs). The PubChem web page was blocked to automated fetch, so its REST JSON was read instead. No atomic-oxygen or outgassing value was found for PAI.
story:
  recipe:
    line: Polyamide-imide is an amorphous thermoplastic whose chain alternates amide and imide links on aromatic rings. It is made from trimellitic anhydride with an aromatic diamine (methylene dianiline) in the acid-chloride route, or with a diisocyanate (MDI) in the route Wikipedia calls the primary one for wire enamels. The aromatic rings and imide groups give thermal stability, and the amide groups give flexibility and elongation (legacy Torlon property sheet).
    parts:
      - name: Trimellitic anhydride
        formula: C9H4O5
        role: Anhydride monomer that supplies the imide rings. Made by air oxidation of 1,2,4-trimethylbenzene (Wikipedia).
      - name: Methylene dianiline (MDA)
        role: Aromatic diamine partner in the acid-chloride route with trimellitic acid chloride, forming the amide links (Wikipedia).
      - name: Methylenediphenyl diisocyanate (MDI)
        role: Partner in the diisocyanate route with trimellitic anhydride, named by Wikipedia as the primary route for wire enamels.
  risk_groups:
    - title: For people
      verdict: The monomer is a sensitiser; no SDS for the polymer was read
      lead: No SDS for the polymer was among the sources checked. The monomer trimellitic anhydride is listed as a sensitiser in PubChem's aggregated notifications.
      points:
        - label: Monomer
          line: 'PubChem''s aggregated notifications list H317, H318, H334 and H335 for trimellitic anhydride: skin sensitisation, serious eye damage, respiratory sensitisation and respiratory irritation.'
        - label: Polymer
          line: No safety data sheet for Torlon resin was read. Syensqo says SDS are available on request.
    - title: In service, heat and moisture
      lead: These come from the design guide's long-term tests on 4203L.
      points:
        - label: Heat
          line: 4203L kept 86 % of its tensile strength after 12,000 h at 250 °C and 67 % after 17,000 h.
        - label: Moisture
          line: Parts absorb water slowly. At 2 % absorbed water, 4203L lost 7 % of its tensile strength and 11 % of its tensile modulus.
    - title: Handling and storage
      points:
        - label: Drying
          line: 'Dry the resin before moulding: at least 3 h at 177 °C (350 °F), or 4 h at 149 °C, or 16 h at 121 °C.'
        - label: Post cure
          line: Moulded parts must be post cured for the best chemical resistance.
  why: Polyamide-imide is used where a plastic has to keep its strength and stiffness at high temperature and still be tough and machinable. The aromatic imide backbone gives the 4203L grade a glass transition of 275 °C, and Syensqo says Torlon has the highest strength and stiffness of any thermoplastic up to 275 °C. The grades are chosen for wear parts, electrical insulators and magnet wire enamel. Torlon 4203L and 4301 have passed NASA's NHB 8060.1 requirements for non-vacuum exposures, which is a flammability and offgassing screen and not a flight test.
  uses:
    - where: Bearings and wear parts
      line: Torlon 4301 is a graphite-filled bearing grade. Syensqo lists thrust washers, spline liners, valve seats, bushings, bearings, wear rings and cams as potential applications.
    - where: Thermal insulators
      line: Drake calls 4203L the best thermal insulator of the Torlon grades and lists thermal insulators and isolators among its typical applications.
    - where: Electrical parts
      line: Aerospace electrical components that need high strength, heat resistance and V-0 flammability are a typical 4203L application (Drake). A reseller sheet adds electrical connectors and insulators for 4203.
    - where: Magnet wire
      line: Wikipedia names magnet wire enamel as the major use of PAI. It is often applied over polyester enamel to reach a higher thermal rating.
    - where: Space materials screen
      line: The design guide says 4203L and 4301 passed NASA's NHB 8060.1 flammability, odour and offgassing requirements for non-vacuum exposures. No flight exposure of PAI was found.
  can_do:
    - label: Heat
      benchmark: heat_deflection_temperature
      value: 279 °C
      line: The 4301 sheet gives a heat deflection temperature of 279 °C at 1.8 MPa for an unannealed part. The 4203L extruded shape gives 278 °C at 264 psi.
    - label: Strength kept at high temperature
      benchmark: flexural_strength
      value: 112 MPa at 232 °C
      line: Torlon 4301 keeps 112 MPa of flexural strength at 232 °C, against 215 MPa at 23 °C.
    - label: Long heat exposure
      value: 67 % of tensile strength at 17,000 h
      line: 4203L keeps 67 % of its tensile strength after 17,000 h at 250 °C, and 86 % after 12,000 h.
    - label: Electrical insulation
      benchmark: dielectric_strength
      value: 580 V/mil
      line: The legacy Torlon table gives 580 V/mil short-time dielectric strength at 1/8 inch for Torlon 4203, and a dielectric constant of 4.2 at 1 MHz.
  compare: 'Torlon PAI sits at the high-temperature end of the amorphous thermoplastics. Its 4203L grade has a glass transition of 275 °C and a heat deflection temperature of 278 °C at 264 psi. Its water uptake is higher than that of the PEI base resin in the PEI profile: 0.4 % in 24 h and 1.7 % at saturation for 4203L, against a lower value for PEI. The PEI profile has the lower water uptake and the lower heat deflection temperature. The tensile values are not compared directly because the two profiles use different test conditions. The table compares the two on heat deflection, tensile strength and water absorption.'
  compare_rows:
    - label: Heat deflection temperature
      benchmark: heat_deflection_temperature
    - label: Tensile strength
      benchmark: ultimate_tensile_strength
    - label: Water absorption
      benchmark: moisture_absorption
  handling:
    - 'Dry the resin before moulding: at least 3 h at 177 °C, with a maximum moisture of 0.050 %.'
    - Post-cure moulded parts to reach the chemical resistance in the design guide.
    - Dry wet parts to restore their size. The design guide used 16 h at 149 °C.
    - Read the supplier SDS before handling the monomer trimellitic anhydride, which PubChem lists as a sensitiser.
  good_for:
    - Strength near 250 °C. 4203L keeps 67 % of its tensile strength after 17,000 h at 250 °C.
    - Wear and friction parts. The graphite-filled 4301 is sold for bearings, thrust washers and wear rings.
    - 'Flame retardance without additives: 4203 and 4301 are both rated UL 94 V-0 in the legacy table.'
  watch_out:
    - 'Water uptake: 1.7 % at saturation for 4203L, with a small change in dimensions and a loss of stiffness.'
    - Saturated steam and strong bases may attack the polymer.
    - 'Atomic oxygen in low Earth orbit: no data found, so no erosion value is recorded.'
  verdict: 'Torlon PAI is a strong, heat-stable thermoplastic for wear parts, insulators and high-temperature moulded parts. The sheets give a glass transition near 275 °C and a heat deflection temperature near 278 °C, and 4203L keeps two thirds of its tensile strength after 17,000 h at 250 °C. The main gaps are space data: no atomic-oxygen or outgassing value was found for PAI.'