spore: profile
id: phenolic-resin
spore_version: 0.2
family: engineering-polymers
name: Phenolic resin (phenol-formaldehyde; Bakelite and phenolic laminates)
abbreviation: PF
role: thermosetting resin for ablative heat shields, laminates and moulded parts
category: polymers
type: epoxies-and-resins
summary: |
  Phenolic resin is a thermoset made by condensing phenol with formaldehyde. Cured, it forms a hard, insoluble network. Bakelite was the first commercial form, developed in 1907 and patented in 1909. NASA's PICA heat shield is a carbon fibre felt impregnated with phenolic resin; it was the Stardust heatshield and is the forebody heatshield for Mars Science Laboratory and the SpaceX Dragon. In a 2019 NASA comparison, the heritage phenolic resin SC1008 left 49% char in inert gas but decomposed from 375 degC, with a lower char yield and a lower glass transition than the newer resins tested.
best_for: 'Char-forming ablators and laminates for gears and bearings, where a hard, machinable thermoset is needed (NEMA LE cotton phenolic: 13 ksi lengthwise tensile)'
weakest_at: Low char yield and low decomposition onset compared with polyimide and cyanate ester, and a lower glass transition than cyanate ester and polybenzoxazine (NASA)
identity:
  formula: 'Phenol polymer with formaldehyde (CAS 9003-35-4): a cross-linked network made by condensing phenol with formaldehyde'
  cas: 9003-35-4
  source: mersen-sds
  where: 'Composition table (ingredients), first row: Phenol polymer with formaldehyde, CAS-No. 9003-35-4'
  designations:
    - system: Trade name
      code: Bakelite
      source: wiki-bakelite
      where: Article title and first paragraph
tags:
  environments:
    - re-entry
  stresses:
    - high-heat-flux
    - humidity
  applications:
    - heat-shields
    - mechanisms
    - electronics-and-chips
properties:
  - benchmark: density
    label: Density, cured phenolic resin SC1008 (heritage ablative resin)
    value: 1.21
    unit: g/cc
    scope: material
    conditions:
      resin: SC1008 heritage phenolic, cured neat resin without a reinforcing matrix
      basis: compression-test specimens of cured resin
    method: Density column of the resin table in the NASA resin characterization (ERC Inc. and NASA Ames), as printed
    status: ground
    source: boghozian2019
    where: Resin density table, Phenolic resin row (slide on compression-test samples)
  - benchmark: decomposition_temperature
    label: Decomposition temperature, cured phenolic resin SC1008
    value: 375
    unit: °C
    scope: material
    conditions:
      resin: SC1008 heritage phenolic, cured neat resin
      atmosphere: inert gas
      heating_rate: 10 C/min
    method: Thermogravimetric analysis, decomposition temperature column, as printed
    status: ground
    source: boghozian2019
    where: TGA results table, SC1008 row (Decomposition temperature column)
  - benchmark: char_yield
    label: Char yield, cured phenolic resin SC1008
    value: 49
    unit: '%'
    scope: material
    conditions:
      resin: SC1008 heritage phenolic, cured neat resin
      atmosphere: inert gas
      heating_rate: 10 C/min
    method: Thermogravimetric analysis, char yield column, as printed; non-canonical benchmark name
    status: ground
    source: boghozian2019
    where: TGA results table, SC1008 row (Char Yield column)
  - benchmark: density
    label: Density, LE-675 cotton fabric phenolic laminate
    value: 1.32
    unit: g/cc
    scope: material
    conditions:
      grade: LE-675 (Phenolite, cotton fabric based laminate)
    method: Density row of the Phenolite grade table, as printed (GM/CC)
    status: ground
    source: midwest-phenolite
    where: Grade table, row Density, LE-675 column
  - benchmark: density
    label: Specific gravity, NEMA LE cotton phenolic laminate
    value: 1.34
    unit: '-'
    scope: material
    conditions:
      grade: NEMA LE (natural or black), cotton based phenolic laminate
    method: Specific gravity printed in the typical values table; test method not printed for this row
    status: ground
    source: gund-datasheet
    where: Typical values table, Specific Gravity row, NEMA LE column
  - benchmark: flash_point
    label: Flash point, uncured phenolic resin product ACE PGY
    value: 100
    unit: °C
    scope: material
    conditions:
      product: ACE PGY uncured phenolic resin (liquid)
      basis: printed as at least 100 degC (lower limit)
    method: Physical properties section of the safety data sheet, as printed with a greater-than-or-equal sign
    status: ground
    source: mersen-sds
    where: Physical and chemical properties section, Flash point row
  - benchmark: max_service_temp
    label: Maximum operating temperature, NEMA LE laminate
    value: 125
    unit: °C
    scope: material
    conditions:
      grade: NEMA LE
      basis: maximum operating temperature, typical value, no time limit printed
    method: Typical values table, Maximum Operating Temperature row; the degree sign is missing in the PDF text layer and reads as 0C there
    status: ground
    source: gund-datasheet
    where: Typical values table, Maximum Operating Temperature row, NEMA LE column
  - benchmark: max_service_temp
    label: Continuous heat resistance, LE-675 laminate (printed in Fahrenheit)
    value: 250
    unit: °F
    scope: material
    conditions:
      grade: LE-675
      basis: heat resistance, continuous, as printed in Fahrenheit
    method: Grade table row Heat Resistance, Farenheit, Continuous, as printed
    status: ground
    source: midwest-phenolite
    where: Grade table, Heat Resistance row, LE-675 column
  - benchmark: ultimate_tensile_strength
    label: Tensile strength lengthwise, NEMA LE laminate
    value: 90
    unit: MPa
    scope: material
    conditions:
      grade: NEMA LE, 0.125 in thickness
      direction: lengthwise
    method: Tensile strength row, ASTM D-638, printed as 13 (90) ksi (MPa); the MPa figure is recorded
    status: ground
    source: gund-datasheet
    where: Key characteristics table, Tensile Strength Lengthwise row, NEMA LE column
  - benchmark: ultimate_tensile_strength
    label: Tensile strength crosswise, NEMA LE laminate
    value: 62
    unit: MPa
    scope: material
    conditions:
      grade: NEMA LE, 0.125 in thickness
      direction: crosswise
    method: Tensile strength row, ASTM D-638, printed as 9 (62) ksi (MPa); the MPa figure is recorded
    status: ground
    source: gund-datasheet
    where: Key characteristics table, Tensile Strength Crosswise row, NEMA LE column
  - benchmark: ultimate_tensile_strength
    label: Tensile strength lengthwise, LE-675 laminate
    value: 13500
    unit: psi
    scope: material
    conditions:
      grade: LE-675
      direction: lengthwise
    method: Grade table row Tensile Strength, PSI, Lengthwise, as printed (13,500 PSI)
    status: ground
    source: midwest-phenolite
    where: Grade table, Tensile Strength Lengthwise row, LE-675 column
  - benchmark: flexural_strength
    label: Flexural strength lengthwise, NEMA LE laminate
    value: 152
    unit: MPa
    scope: material
    conditions:
      grade: NEMA LE
      direction: lengthwise
    method: Flexural strength row, printed as 22 (152) ksi (MPa); the test method is printed as ASTM D-695 on that row
    status: ground
    source: gund-datasheet
    where: Key characteristics table, Flexural Strength Lengthwise row, NEMA LE column
  - benchmark: flexural_strength
    label: Flexural strength crosswise, NEMA LE laminate
    value: 110
    unit: MPa
    scope: material
    conditions:
      grade: NEMA LE
      direction: crosswise
    method: Flexural strength row, printed as 16 (110) ksi (MPa); the test method is printed as ASTM D-695 on that row
    status: ground
    source: gund-datasheet
    where: Key characteristics table, Flexural Strength Crosswise row, NEMA LE column
  - benchmark: shear_strength
    label: Shear strength, NEMA LE laminate
    value: 93
    unit: MPa
    scope: material
    conditions:
      grade: NEMA LE
    method: Shear strength row, ASTM D-732, printed as 13.5 (93) ksi (MPa); the MPa figure is recorded
    status: ground
    source: gund-datasheet
    where: Key characteristics table, Shear Strength row, NEMA LE column
  - benchmark: moisture_absorption
    label: Moisture absorption, NEMA LE laminate
    value: 1.9
    unit: '%'
    scope: material
    conditions:
      grade: NEMA LE
      test: ASTM D-570 (test exposure not printed on the sheet)
    method: Moisture absorption row, ASTM D-570, as printed
    status: ground
    source: gund-datasheet
    where: Key characteristics table, Moisture Absorption row, NEMA LE column
  - benchmark: dielectric_strength
    label: Dielectric strength, NEMA LE laminate, Condition A
    value: 625
    unit: V/mil
    scope: material
    conditions:
      grade: NEMA LE
      thickness: 0.062 in
      condition: A (as printed)
    method: Dielectric strength row, Condition A column, as printed in V/mil
    status: ground
    source: gund-datasheet
    where: Key characteristics table, Dielectric Strength (0.062 in) row, Condition A, NEMA LE column
corrosion:
  - environment: Thermal decomposition in inert gas, heated at 10 C/min (thermogravimetric analysis)
    headline: The heritage cured phenolic starts to decompose at 375 °C and leaves 49% char.
    effect: Decomposition begins at 375 °C and the char yield is 49%, lower than polyimide and cyanate ester in the same table. NASA lists low char yield and low decomposition onset as phenolic weaknesses.
    rating: moderate
    conditions:
      atmosphere: inert gas
      heating_rate: 10 C/min
    source: boghozian2019
    where: TGA results table; Objective and Motivation slide
  - environment: Continuous service temperature (NEMA LE laminate, typical value)
    headline: The datasheet prints a maximum operating temperature of 125 °C and no ageing data.
    effect: The sheet gives a typical maximum operating temperature only. No time at temperature or property retention is printed, so the rating is unknown.
    rating: unknown
    conditions:
      grade: NEMA LE
    source: gund-datasheet
    where: Typical values table, Maximum Operating Temperature row
  - environment: Humidity, ASTM D-570 moisture absorption (NEMA LE laminate)
    headline: The laminate absorbs 1.9% moisture under the ASTM D-570 test.
    effect: Moisture absorption is printed as 1.9%. The same sheet prints 3.5% for the NEMA C grade, so the LE grade absorbs less moisture than C.
    rating: low
    conditions:
      grade: NEMA LE
      test: ASTM D-570
    source: gund-datasheet
    where: Key characteristics table, Moisture Absorption row
risks:
  hazards:
    - text: 'Mersen safety data sheet for the uncured ACE PGY phenolic resin: signal word Danger; causes severe skin burns and eye damage (H314), may cause an allergic skin reaction (H317) and is harmful if inhaled (H332).'
      ghs:
        - H314
        - H317
        - H332
      source: mersen-sds
      where: Hazard statements (CLP) block of the safety data sheet
    - text: The same SDS also lists suspected genetic defects (H341), may cause cancer (H350), may damage fertility or the unborn child (H360), may cause organ damage on repeated exposure (H373) and harmful to aquatic life with long lasting effects (H412).
      ghs:
        - H341
        - H350
        - H360
        - H373
        - H412
      source: mersen-sds
      where: Hazard statements (CLP) block of the safety data sheet
  failure_risks:
    - mode: Thermal decomposition of the cured resin
      trigger: Heating above the onset in inert gas at 10 C/min
      consequence: Mass loss starts at 375 °C; the heritage resin leaves 49% char.
      severity: moderate
      source: boghozian2019
      where: TGA results table, SC1008 row
    - mode: Softening as the matrix nears its glass transition
      trigger: Heating toward the glass transition temperature of the resin
      consequence: NASA reports that phenolic has a lower glass transition than cyanate ester and polybenzoxazine, so the matrix softens sooner and mechanical properties drop. The Tg value itself was not read.
      severity: moderate
      source: boghozian2019
      where: Glass transition slide, phenolic comparison
    - mode: Lot-to-lot density variation in carbon-phenolic ablator billets
      trigger: Manufacturing spread in PICA billets
      consequence: NASA notes significant density variation in PICA billets, which matters for lot acceptance and for thermal sizing.
      severity: low
      source: ellerby2019
      where: Slide titled PICA Billet Has Significant Variability in Density
    - mode: Moisture uptake in service
      trigger: Humid air or immersion (ASTM D-570 test)
      consequence: The NEMA LE laminate absorbs 1.9% moisture by mass under the printed test.
      severity: low
      source: gund-datasheet
      where: Key characteristics table, Moisture Absorption row
  side_effects: []
  handling:
    - text: Wear gloves and eye protection; the SDS classes the uncured resin as causing severe skin burns and eye damage and as a skin sensitiser.
      source: mersen-sds
      where: Hazard statements (CLP) block; handling section
    - text: During processing, vapours of phenol and benzaldehyde may be released; use ventilation, and an approved respirator when exposed to vapours from heated material, as the SDS advises.
      source: mersen-sds
      where: Additional hazards when processed; exposure controls section
  mitigations: []
uses:
  - application: heat-shields
    device: Ablative heatshield, PICA carbon phenolic
    example: PICA, a carbon fibre insulation impregnated with phenolic resin, was the Stardust heatshield and is the forebody heatshield for Mars Science Laboratory and the SpaceX Dragon.
    source: milos-pica2009
    where: Section I (Introduction)
  - application: heat-shields
    device: Phenolic-nylon charring ablator test material (1960s)
    example: The high-density phenolic-nylon ablator in a 1965 NASA study was 50% by weight Union Carbide Bakelite BRP-5549 phenolic resin.
    source: tnd2991-1965
    where: Test materials, high-density phenolic-nylon description
  - application: mechanisms
    device: Gears, pinions and bearings
    example: The Gund datasheet describes NEMA C, CE and LE cotton phenolic laminates as suited to gears, pinions and bearings.
    source: gund-datasheet
    where: Product description paragraph
  - application: electronics-and-chips
    device: Electrical insulating bushings
    example: The earliest commercial electrical use of Bakelite was insulating bushings made in 1908 for the Weston Electrical Instrument Corporation.
    source: wiki-bakelite
    where: Main uses section
story:
  recipe:
    line: Phenol and formaldehyde react in a condensation reaction, with an acid or base catalyst, to give a soluble intermediate that hardens under heat and pressure into an insoluble, hard resin. Phenol is made mainly by the cumene process, the dominant industrial route.
    parts:
      - name: Phenol
        role: The aromatic monomer; its hydroxyl-bearing ring joins to formaldehyde at the ring positions to build the network.
      - name: Formaldehyde
        role: The cross-linking monomer that links phenol rings together.
  risk_groups:
    - title: For people
      level: 0
      verdict: Uncured resin corrosive and a sensitiser
      lead: The uncured ACE PGY resin is classed in the Mersen SDS as corrosive to skin and eyes and as a skin sensitiser.
      points:
        - label: Skin and eyes
          line: Causes severe skin burns and eye damage (H314) and may cause an allergic skin reaction (H317), per the SDS.
    - title: In heating
      verdict: Chars well, softens and decomposes early
      lead: Heritage phenolic gives 49% char in inert gas but starts to decompose at 375 degC, with a lower glass transition than the newer resins NASA tested.
      points:
        - label: Char
          line: The heritage resin SC1008 leaves 49% char at 10 C/min in inert gas.
  why: Phenolic resins are used where a char-forming, heat-resistant thermoset is needed. PICA, a carbon fibre felt impregnated with phenolic resin, has flown as a heat shield on Stardust and is used on Mars Science Laboratory and SpaceX Dragon. Phenolic laminates are used for gears, pinions and bearings because they are tough and machinable. NASA's comparison shows the heritage resin's weak points, low char yield and a low decomposition onset.
  uses:
    - where: Heat shields
      line: PICA, a phenolic-impregnated carbon ablator, was the Stardust heatshield and is the forebody heatshield for Mars Science Laboratory and SpaceX Dragon.
    - where: Gears and bearings
      line: NEMA LE cotton phenolic laminate is printed as suited to gears, pinions and bearings, with a 90 MPa lengthwise tensile strength.
  can_do:
    - label: Char yield
      value: 49%
      line: The heritage resin SC1008 left 49% char at 10 C/min in inert gas.
    - label: Cured resin density
      value: 1.21 g/cc
      line: The cured SC1008 resin has a density of 1.21 g/cc, as printed in the NASA resin table.
    - label: Continuous service
      value: 125 °C
      line: The NEMA LE laminate has a printed maximum operating temperature of 125 °C.
  compare: Phenolic is the heritage ablative resin. NASA's 2019 resin study compared it with cyanate ester, polybenzoxazine, polyimidazole and polyimide. Phenolic had a lower char yield and a lower decomposition onset than polyimide and cyanate ester in the same table, and a lower glass transition than cyanate ester and polybenzoxazine. The laminate grades are cotton based; their tensile values are typical, not specification values.
  compare_rows:
    - label: Density
      benchmark: density
    - label: Maximum service temperature
      benchmark: max_service_temp
    - label: Flexural strength
      benchmark: flexural_strength
  handling:
    - Wear gloves and eye protection; the uncured resin is corrosive to skin and eyes and is a skin sensitiser.
    - Process with ventilation; phenol and benzaldehyde vapours are released during processing.
  good_for:
    - Char-forming heat shields, where the char carries heat away on re-entry.
    - Machinable laminate gears, pinions and bearings made from cotton phenolic grades.
  watch_out:
    - Low char yield and a low decomposition onset compared with polyimide and cyanate ester.
    - Lower glass transition than cyanate ester and polybenzoxazine, so the matrix softens earlier.
    - PICA billets vary in density, which changes thermal sizing and lot acceptance.
  verdict: Phenolic resin is a proven, cheap heat-shield and laminate resin with heritage flight use, but NASA's own comparison shows low char yield and a low glass transition. Newer resins are being developed to beat it.
gaps:
  - No glass transition temperature for the cured phenolic was read. The NASA resin slide gives a 260 degC value but does not tie it to a resin clearly, so no Tg is used.
  - No UV, atomic oxygen or chemical resistance data for cured phenolic was read. The one ageing search returned no UV or hygrothermal study for cured phenolic.
  - No thermal ageing data beyond the continuous service limit printed on the datasheet.
  - 'No supply data: producer country shares for phenol and formaldehyde were not found in a source read in this run. The Wikipedia phenol article names the cumene process as dominant but gives no country shares.'
  - Critical-mineral status was not checked; the feedstocks are petrochemical and no USGS or EU list entry was opened.
  - The PubChem GHS summary for CAS 9003-35-4 could not be read (reCAPTCHA page). Hazards come from the Mersen SDS for one uncured resin product only.
  - Hazard data apply to the uncured ACE PGY resin, not to a cured laminate or the NEMA grades.
  - PICA numeric properties (density, thermal conductivity, heat capacity, char density) are not printed in the Milos and Chen paper, which withholds them under export control, and the 2019 NASA slides show only normalised plots. No numeric PICA or carbon-phenolic property was read.
  - A Japanese carbon-phenolic density range appeared only in a search snippet and is not used.
  - 'Non-canonical benchmark names in use: decomposition_temperature and char_yield are not in spores/property-canon.yaml.'
  - 'Designations: NEMA LI-1 grade codes (C, CE, LE) and IEC 60893 codes (PFCC 201, 202, 204) do not fit the designation systems list, so they are not recorded.'
  - No thermoset type exists in src/data/taxonomy.ts. The closest type, epoxies-and-resins, is used.
  - The Gund datasheet prints the maximum operating temperature unit with the degree sign lost in the PDF text layer; 125 is read in degrees Celsius from the same row.
  - The Midwest Composites page gives LE-675 lengthwise tensile as 13,500 PSI; an earlier search snippet gave 14,000, which is not used.
sources:
  boghozian2019:
    title: Characterization of New TPS Resins
    id: NTRS 20190033961; T. Boghozian (ERC International), M. Stackpoole (NASA Ames), G. Gonzales (ERC International); NSMMS and CRASTE Joint Symposia, June 2019
    url: https://ntrs.nasa.gov/citations/20190033961
    year: 2019
    kind: report
    license: NASA NTRS public record
  gund-datasheet:
    title: NEMA C, CE, LE Phenolic Resin Cotton Cloth technical data sheet
    id: The Gund Company, TCGR 03/2023
    url: https://thegundcompany.com/wp-content/uploads/2025/12/NEMA-C-CE-LE-Phenolic-Resin-Cotton-Cloth-by-The-Gund-Co.pdf
    year: 2023
    kind: datasheet
    license: manufacturer datasheet, cited
  midwest-phenolite:
    title: Phenolite cotton fabric based laminate grade specifications
    id: Midwest Composites, cotspecs grade table (undated page)
    url: https://midwestcomposites.clearlight.com/cotspecs.htm
    kind: datasheet
    license: manufacturer datasheet, cited
  mersen-sds:
    title: ACE PGY phenolic resin, safety data sheet (English)
    id: Mersen, 2023
    url: https://de.mersen.com/sites/default/files/files_imported/ace-pgy-phenolic-resin-english-2023.pdf
    year: 2023
    kind: datasheet
    license: manufacturer SDS, cited
  wiki-bakelite:
    title: Bakelite
    id: Wikipedia article, read 2026-10-26
    url: https://en.wikipedia.org/wiki/Bakelite
    kind: web
    license: CC BY-SA 4.0
  wiki-phenol:
    title: Phenol
    id: Wikipedia article, read 2026-10-26
    url: https://en.wikipedia.org/wiki/Phenol
    kind: web
    license: CC BY-SA 4.0
  milos-pica2009:
    title: Ablation and Thermal Response Property Model Validation for Phenolic Impregnated Carbon Ablator
    id: AIAA-2009-0262; F.S. Milos and Y.-K. Chen, NASA Ames, 47th AIAA Aerospace Sciences Meeting, January 2009; NTRS 20110012891
    url: https://ntrs.nasa.gov/citations/20110012891
    year: 2009
    kind: paper
    license: NASA NTRS public record
  ellerby2019:
    title: Thermal Properties - Do We Trust Them? Yes'ish (panel discussion slides)
    id: Don Ellerby, NASA Ames; 30th Annual Thermal and Fluids Analysis Workshop, August 26, 2019; NTRS 20190030277
    url: https://ntrs.nasa.gov/api/citations/20190030277/downloads/20190030277.pdf
    year: 2019
    kind: report
    license: NASA NTRS public record
  tnd2991-1965:
    title: Thermophysical properties of six charring ablators from 140 to 700 K and two chars from 800 to 3000 K
    id: NASA TN D-2991, 1965; NTRS 19650024901
    url: https://ntrs.nasa.gov/citations/19650024901
    year: 1965
    kind: report
    license: NASA NTRS public record
documents:
  - type: sds
    title: ACE PGY phenolic resin, safety data sheet (English)
    url: https://de.mersen.com/sites/default/files/files_imported/ace-pgy-phenolic-resin-english-2023.pdf
  - type: datasheet
    title: NEMA C, CE, LE Phenolic Resin Cotton Cloth technical data sheet
    url: https://thegundcompany.com/wp-content/uploads/2025/12/NEMA-C-CE-LE-Phenolic-Resin-Cotton-Cloth-by-The-Gund-Co.pdf
  - type: report
    title: Characterization of New TPS Resins
    url: https://ntrs.nasa.gov/citations/20190033961
  - type: paper
    title: Ablation and Thermal Response Property Model Validation for Phenolic Impregnated Carbon Ablator
    url: https://ntrs.nasa.gov/citations/20110012891
review:
  status: draft
  method: assistant
  checked_values: 16
  caveats: 9
  note: Written by an AI assistant from pages and PDFs read in this run; 16 values, 9 sources. Tg, UV and atomic oxygen ageing, supply shares and PICA numeric properties were not found in a readable source.
updated: '2026-10-26'
license: CC-BY-4.0