spore: profile
id: ppo
spore_version: 0.2
family: engineering-polymers
name: Polyphenylene oxide
abbreviation: PPO
role: amorphous high-temperature thermoplastic, used mainly as a blend with polystyrene (Noryl) for electrical and office-equipment parts
category: polymers
type: polyethers
summary: |
  Polyphenylene oxide (PPO, also called poly(p-phenylene ether) or PPE) is an amorphous thermoplastic with the repeat unit (C8H8O)n, made by oxidative coupling of 2,6-xylenol. The neat resin is hard to process, so it is sold mostly as blends with polystyrene under the Noryl name. The neat PPO powder read (Polysciences product 08794) has a glass transition temperature of 209 °C and a density of 1.06 g/mL. The two SABIC Noryl grades read are PPE/PS blends: PX9406P has a density of 1.1 g/cm3, a 136 °C heat deflection temperature at 0.45 MPa and a 73 MPa tensile strength at yield, and the 15 % glass-fibre grade NHP9023 has a density of 1.21 g/cm3, a 154 °C heat deflection temperature at 1.82 MPa and a 112 MPa tensile strength at break. Water uptake is low, at 0.07 % after 24 hours for PX9406P. No atomic-oxygen erosion yield, UV retention figure or outgassing row for PPO was found in the sources read.
best_for: 'Stiff, low-water-uptake electrical and office-equipment parts that run at up to about 150 °C: PX9406P has a 136 °C HDT at 0.45 MPa and NHP9023 has 154 °C at 1.82 MPa'
weakest_at: 'Ductility and processing: the glass-fibre grade breaks at 2.7 % elongation and the PX9406P grade at 8 %, and the neat resin is hard to process without a blend partner (Wikipedia)'
identity:
  formula: (C8H8O)n, poly(oxy-2,6-dimethyl-1,4-phenylene), made by oxidative coupling of 2,6-xylenol
  cas: 25134-01-4
  source: wikipedia-ppo
  where: Infobox and introduction, CAS number 25134-01-4 and repeat-unit name; the same CAS is printed in the Polysciences product description and in the MHLW GHS database. Monomer and process from 21 CFR 177.2460, paragraph (a).
  designations:
    - system: Trade name
      code: Noryl
      source: wikipedia-ppo
      where: History section, modified PPE sold under the Noryl trademark
    - system: Trade name
      code: PPO
      source: wikipedia-ppo
      where: Manufacturers section, SABIC Innovative Plastics holds the PPO trademark
tags:
  environments: []
  stresses:
    - extreme-heat
  applications:
    - electronics-and-chips
    - mechanisms
properties:
  - benchmark: density
    label: Density, Noryl PX9406P (PPE/PS blend)
    value: 1.1
    unit: g/cm3
    scope: material
    conditions:
      grade: PX9406P (NORYL), PPE/PS blend, not reinforced
      test_standard: ISO 1183
    method: Value printed on the SABIC SHPP Japan datasheet listing on PlaBase
    status: ground
    source: plabase-px9406p
    where: Basic Properties table, Density row, ISO 1183
  - benchmark: density
    label: Density, Noryl NHP9023 (PPE/PS, 15 % glass fibre)
    value: 1.21
    unit: g/cm3
    scope: material
    conditions:
      grade: NHP9023 (NORYL), PPE/PS blend with 15 % glass fibre
      test_standard: ISO 1183
    method: Value printed on the SABIC SHPP Japan datasheet listing on PlaBase
    status: ground
    source: plabase-nhp9023
    where: Basic Properties table, Density row, ISO 1183
  - benchmark: density
    label: Density, neat PPO powder (Polysciences 08794)
    value: 1.06
    unit: g/mL
    scope: material
    conditions:
      product: Poly(2,6-dimethyl-1,4-phenylene oxide), neat, white to off-white powder
      test_standard: not printed
    method: Value in the product specification table of the supplier listing
    status: ground
    source: polysciences-08794
    where: Specification table, Density row
  - benchmark: glass_transition_temperature
    label: Glass transition temperature, neat PPO powder (Polysciences 08794)
    value: 209
    unit: °C
    scope: material
    conditions:
      product: Poly(2,6-dimethyl-1,4-phenylene oxide), neat, Mn about 20,000 per the description
      test_standard: not printed
    method: Value in the product specification table of the supplier listing
    status: ground
    source: polysciences-08794
    where: Specification table, Glass transition temperature row
  - benchmark: vicat_softening_temperature
    label: Vicat softening point (rate A/120), Noryl PX9406P
    value: 150
    unit: °C
    scope: material
    conditions:
      grade: PX9406P (NORYL), PPE/PS blend
      test_standard: ISO 306
    method: Value printed on the SABIC SHPP Japan datasheet listing on PlaBase
    status: ground
    source: plabase-px9406p
    where: Thermal Properties table, Vicat softening point (Rate A/120) row, ISO 306
  - benchmark: heat_deflection_temperature
    label: Heat deflection temperature at 0.45 MPa, Noryl PX9406P
    value: 136
    unit: °C
    scope: material
    conditions:
      grade: PX9406P (NORYL), PPE/PS blend, 6.4 mm, no annealing
      load: 0.45 MPa
      test_standard: ASTM D648
    method: Value printed on the SABIC SHPP Japan datasheet listing on PlaBase
    status: ground
    source: plabase-px9406p
    where: Thermal Properties table, HDT (0.45 MPa, 6.4 mm, no annealing) row, ASTM D648
  - benchmark: heat_deflection_temperature
    label: Heat deflection temperature at 1.82 MPa, Noryl PX9406P
    value: 122
    unit: °C
    scope: material
    conditions:
      grade: PX9406P (NORYL), PPE/PS blend, 6.4 mm, no annealing
      load: 1.82 MPa
      test_standard: ASTM D648
    method: Value printed on the SABIC SHPP Japan datasheet listing on PlaBase
    status: ground
    source: plabase-px9406p
    where: Thermal Properties table, HDT (1.82 MPa, 6.4 mm, no annealing) row, ASTM D648
  - benchmark: heat_deflection_temperature
    label: Heat deflection temperature at 1.82 MPa, Noryl NHP9023 (15 % glass)
    value: 154
    unit: °C
    scope: material
    conditions:
      grade: NHP9023 (NORYL), PPE/PS blend with 15 % glass fibre, 6.4 mm, no annealing
      load: 1.82 MPa
      test_standard: ASTM D648
    method: Value printed on the SABIC SHPP Japan datasheet listing on PlaBase
    status: ground
    source: plabase-nhp9023
    where: Thermal Properties table, HDT (1.82 MPa, 6.4 mm, no annealing) row, ASTM D648
  - benchmark: yield_strength
    label: Tensile strength at yield, Noryl PX9406P
    value: 73
    unit: MPa
    scope: material
    conditions:
      grade: PX9406P (NORYL), PPE/PS blend, unfilled
      speed: 50 mm/min
      test_standard: ISO 527
    method: Value printed on the SABIC SHPP Japan datasheet listing on PlaBase
    status: ground
    source: plabase-px9406p
    where: Mechanical Properties table, Tensile strength (yield point) row, ISO 527
  - benchmark: ultimate_tensile_strength
    label: Tensile strength at break, Noryl NHP9023 (15 % glass)
    value: 112
    unit: MPa
    scope: material
    conditions:
      grade: NHP9023 (NORYL), PPE/PS blend with 15 % glass fibre
      speed: 5 mm/min
      test_standard: ISO 527
    method: Value printed on the SABIC SHPP Japan datasheet listing on PlaBase
    status: ground
    source: plabase-nhp9023
    where: Mechanical Properties table, Tensile strength (break point) row, ISO 527
  - benchmark: elongation
    label: Elongation at break, Noryl PX9406P
    value: 8
    unit: '%'
    scope: material
    conditions:
      grade: PX9406P (NORYL), PPE/PS blend, unfilled
      speed: 50 mm/min
      test_standard: ISO 527
    method: Value printed on the SABIC SHPP Japan datasheet listing on PlaBase
    status: ground
    source: plabase-px9406p
    where: Mechanical Properties table, Tensile elongation (break point) row, ISO 527
  - benchmark: elongation
    label: Elongation at break, Noryl NHP9023 (15 % glass)
    value: 2.7
    unit: '%'
    scope: material
    conditions:
      grade: NHP9023 (NORYL), PPE/PS blend with 15 % glass fibre
      speed: 5 mm/min
      test_standard: ISO 527
    method: Value printed on the SABIC SHPP Japan datasheet listing on PlaBase
    status: ground
    source: plabase-nhp9023
    where: Mechanical Properties table, Tensile elongation (break point) row, ISO 527
  - benchmark: flexural_modulus
    label: Flexural modulus, Noryl PX9406P
    value: 2500
    unit: MPa
    scope: material
    conditions:
      grade: PX9406P (NORYL), PPE/PS blend, unfilled
      speed: 2 mm/min
      test_standard: ISO 178
    method: Value printed on the SABIC SHPP Japan datasheet listing on PlaBase
    status: ground
    source: plabase-px9406p
    where: Mechanical Properties table, Bending elasticity (2 mm/min) row, ISO 178
  - benchmark: flexural_modulus
    label: Flexural modulus, Noryl NHP9023 (15 % glass)
    value: 5200
    unit: MPa
    scope: material
    conditions:
      grade: NHP9023 (NORYL), PPE/PS blend with 15 % glass fibre
      speed: 2 mm/min
      test_standard: ISO 178
    method: Value printed on the SABIC SHPP Japan datasheet listing on PlaBase
    status: ground
    source: plabase-nhp9023
    where: Mechanical Properties table, Bending elasticity (2 mm/min) row, ISO 178
  - benchmark: flexural_strength
    label: Flexural strength (yield point), Noryl NHP9023 (15 % glass)
    value: 163
    unit: MPa
    scope: material
    conditions:
      grade: NHP9023 (NORYL), PPE/PS blend with 15 % glass fibre
      speed: 2 mm/min
      test_standard: ISO 178
    method: Value printed on the SABIC SHPP Japan datasheet listing on PlaBase
    status: ground
    source: plabase-nhp9023
    where: Mechanical Properties table, Bending strength (yield point) row, ISO 178
  - benchmark: notched_izod_impact
    label: Notched Izod impact strength at 23 °C, Noryl PX9406P
    value: 140
    unit: J/m
    scope: material
    conditions:
      grade: PX9406P (NORYL), PPE/PS blend, unfilled
      temperature: 23 °C
      test_standard: ASTM D256
    method: Value printed on the SABIC SHPP Japan datasheet listing on PlaBase
    status: ground
    source: plabase-px9406p
    where: Mechanical Properties table, Izod impact strength (notched, 23 °C) row, ASTM D256
  - benchmark: moisture_absorption
    label: Water absorption, 24 hours, Noryl PX9406P
    value: 0.07
    unit: '%'
    scope: material
    conditions:
      grade: PX9406P (NORYL), PPE/PS blend
      time: 24 hours
      test_standard: ASTM D570
    method: Value printed on the SABIC SHPP Japan datasheet listing on PlaBase
    status: ground
    source: plabase-px9406p
    where: Basic Properties table, Water absorption rate (24 hours) row, ASTM D570
  - benchmark: moisture_absorption
    label: Water absorption at saturation, 23 °C, Noryl NHP9023 (15 % glass)
    value: 0.2
    unit: '%'
    scope: material
    conditions:
      grade: NHP9023 (NORYL), PPE/PS blend with 15 % glass fibre
      temperature: 23 °C, saturation
      test_standard: ISO 62
    method: Value printed on the SABIC SHPP Japan datasheet listing on PlaBase
    status: ground
    source: plabase-nhp9023
    where: Basic Properties table, Water absorption (23 °C/sat) row, ISO 62
  - benchmark: dielectric_constant
    label: Dielectric constant at 50/60 Hz, Noryl PX9406P
    value: 2.8
    unit: '-'
    scope: material
    conditions:
      grade: PX9406P (NORYL), PPE/PS blend
      frequency: 50/60 Hz
      test_standard: ASTM D150
    method: Value printed on the SABIC SHPP Japan datasheet listing on PlaBase; the unit column is blank on the page and the value is dimensionless
    status: ground
    source: plabase-px9406p
    where: Electrical Properties table, Dielectric constant, 50/60 Hz row, ASTM D150
  - benchmark: cte
    label: Coefficient of thermal expansion, flow direction, -40 to +40 °C, Noryl PX9406P
    value: 0.00008
    unit: /°C
    scope: material
    conditions:
      grade: PX9406P (NORYL), PPE/PS blend
      direction: flow
      range: '-40 to +40 °C'
      test_standard: ISO 11359-2
    method: Printed as 8 x10^-5 per °C on the SABIC SHPP Japan datasheet listing on PlaBase
    status: ground
    source: plabase-px9406p
    where: Thermal Properties table, CTE (-40 to +40 °C) flow direction row, ISO 11359-2
corrosion:
  - environment: Humidity and water uptake
    headline: Low water uptake, 0.07 % after 24 hours for Noryl PX9406P.
    effect: The PX9406P datasheet gives 0.07 % water absorption after 24 hours at 23 °C under ASTM D570. The glass-fibre grade NHP9023 reaches 0.2 % at saturation under ISO 62, which is a longer test, so the two figures are not directly comparable.
    conditions:
      basis: datasheet values for PPE/PS blends, short-term immersion
    source: plabase-px9406p
    where: Basic Properties table, Water absorption rate (24 hours) row
    rating: low
  - environment: Heat in service
    headline: Heat deflection temperature is 136 °C at 0.45 MPa and 122 °C at 1.82 MPa for PX9406P, and 154 °C at 1.82 MPa for NHP9023.
    effect: These are short-term load-deflection temperatures under ASTM D648 with no annealing. They show where stiffness starts to fall under load. No long-term heat-ageing or continuous-use figure was read.
    conditions:
      basis: short-term load test, 6.4 mm bars, no annealing
    source: plabase-px9406p
    where: Thermal Properties table, HDT rows, ASTM D648
    rating: unknown
risks:
  hazards:
    - text: The Japanese GHS safety data sheet for poly(2,6-dimethyl-1,4-phenylene oxide), CAS 25134-01-4, gives the signal word Warning, an exclamation mark and a health-hazard pictogram, and the statements that it may cause respiratory irritation and may cause respiratory damage through prolonged or repeated inhalation. The H-code list was not legible in the text read.
      ghs: []
      source: mhlw-ghs-25134-01-4
      where: GHS classification table and hazard statements, Warning signal word
    - text: The Polysciences listing says "Harmless-use normal precautions" with hazard code A2g and no GHS statements, which conflicts with the GHS classification above. The GHS entry is used here as the more specific source.
      ghs: []
      source: polysciences-08794
      where: Safety and hazards field, hazard code A2g
    - text: The fire hazard and flash point fields are marked not applicable, and the page gives irritating and toxic gases in a fire without naming them.
      ghs: []
      source: mhlw-ghs-25134-01-4
      where: Flammability row and fire-fighting statement
  failure_risks:
    - mode: Loss of stiffness under sustained load at elevated temperature
      trigger: Load applied at temperatures near the heat deflection point, 122 °C at 1.82 MPa for PX9406P or 136 °C at 0.45 MPa
      consequence: Stiffness falls and deflection increases under load; the HDT figures are short-term test values, not a rated service limit.
      severity: moderate
      source: plabase-px9406p
      where: Thermal Properties table, HDT rows, ASTM D648
  side_effects: []
  handling:
    - text: Avoid breathing dust, keep the container tightly closed, and use the material outdoors or in a well-ventilated area, as the GHS entry requires.
      source: mhlw-ghs-25134-01-4
    - text: Store in a well-ventilated place with the container closed and locked up, as printed on the GHS entry.
      source: mhlw-ghs-25134-01-4
  mitigations: []
uses:
  - application: electronics-and-chips
    device: Internal parts of office equipment, including a copier fuser unit
    example: Fuser unit of copy machine and internal components of office equipment, as listed for the glass-fibre Noryl grade NHP9023.
    source: plabase-nhp9023
    where: Main applications line on the datasheet listing
  - application: electronics-and-chips
    device: Electronics components
    example: Electronics, as a stated application of the neat PPO powder (Polysciences product 08794).
    source: polysciences-08794
    where: Stated applications list
  - application: mechanisms
    device: Automotive components
    example: Automotive components, as a stated application of the neat PPO powder (Polysciences product 08794).
    source: polysciences-08794
    where: Stated applications list
supply:
  - subject: Polyphenylene oxide, production route
    demand: No tonnage or demand figure was read for PPO in this run.
    routes: Oxidative coupling of 2,6-xylenol. 21 CFR 177.2460 describes the resin as produced by this process, with diethylamine as the residual catalyst.
    producers: []
    abundance: 2,6-xylenol is the feedstock named in the regulation. No feedstock tonnage or abundance was read.
    critical_lists: []
    substitutes: []
    source: cfr-177-2460
    where: Paragraph (a), production by oxidative coupling of 2,6-xylenol
  - subject: Polyphenylene oxide, producers
    demand: No tonnage or country share was read.
    routes: Not described on the Wikipedia page read.
    producers: []
    abundance: SABIC Innovative Plastics holds the PPO trademark and sells various polyphenylene ether resins under it. No other producer is named in the source read.
    critical_lists: []
    substitutes: []
    source: wikipedia-ppo
    where: Manufacturers and trade names section
documents:
  - title: SABIC SHPP Japan, NORYL PX9406P datasheet (PlaBase listing)
    type: datasheet
    url: https://en.plabase.com/plastic/items/5ebc224543428b0a5418c2f6
    year: 2026
  - title: SABIC SHPP Japan, NORYL NHP9023 datasheet (PlaBase listing)
    type: datasheet
    url: https://en.plabase.com/plastic/items/5ebc223f43428b0a5418b7e8
    year: 2026
  - title: Polysciences, Poly(2,6-dimethyl-1,4-phenylene oxide), product 08794
    type: datasheet
    url: https://www.polysciences.com/default/poly26-dimethyl-14-phenylene-oxide
    year: 2026
  - title: Japan GHS safety data sheet, Poly(2,6-dimethyl-1,4-phenylene oxide), CAS 25134-01-4
    type: sds
    url: https://anzeninfo.mhlw.go.jp/anzen/gmsds/25134-01-4.html
    year: 2021
  - title: 21 CFR 177.2460, Poly(2,6-dimethyl-1,4-phenylene) oxide resins
    type: standard
    url: https://www.law.cornell.edu/cfr/text/21/177.2460
    year: 2026
gaps:
  - 'UV and sunlight ageing of PPO: no retention figure was read. A thesis on PPO photodegradation (IIT Delhi) was found, but its PDF is scanned images with no readable text in this run.'
  - 'Atomic oxygen erosion yield for PPO: not found. The search returned phenylphosphine oxide polymers, which are a different material.'
  - 'Outgassing (TML, CVCM, WVR) for PPO or PPE: the Gund Company bulletin PDF was read, and its table has a PPS row but no PPO or PPE row.'
  - 'Chemical resistance by solvent, acid or base with numbers: not found. No qualitative statement was read for PPO.'
  - 'Heat ageing at long-term service temperature: no figure was read. The HDT values above are short-term test results.'
  - 'Radiation, thermal cycling and cryogenic data for PPO in space: none read.'
  - 'Melting point: none printed on the Polysciences page or the two Noryl datasheets read.'
  - 'Dielectric strength, UL 94 rating and oxygen index: not printed on the PX9406P or NHP9023 datasheets read.'
  - Neat PPO properties are from one supplier powder only (Polysciences 08794). The other values are for PPE/PS blends, which are not neat PPO. The Polysciences page gives CAS 25134-01-4 in its description and 25134-01-04 in its specification table; the first form is used.
  - 'Polysciences molecular weight conflicts with itself: 50000 in the specification table, and Mn 20,000 with polydispersity about 2.5 in the description. Neither is used.'
  - 'Japanese GHS database: the H-code list was not legible in the text read, so no H-codes are given. The signal word, pictograms and hazard statements are given as the page prints them. The text read was machine-decoded from Japanese and paraphrased, so the wording is not exact.'
  - PubChem record for CAS 25134-01-4 was not reached (verification page). No PubChem GHS data is used.
  - 'Producer tonnages, country shares and critical-mineral lists for PPO: not found. The producer list on Wikipedia has only SABIC.'
  - 'Standard designations (UNS, EN, DIN, JIS, AISI, ASTM) for PPO as a material: none printed in the sources read. Only trade names are listed.'
  - 'Non-canonical property name used: notched_izod_impact. Dielectric constant unit is blank on the PX9406P page, so it is taken as dimensionless (-).'
  - UL Prospector and SpecialChem pages returned HTTP 403 and were not read. Wikipedia glass transition of 215 °C is not used because Wikipedia is used for composition and history only.
  - 'CTE of the glass-fibre grade NHP9023, 23 to 80 °C flow direction, printed as 3.5 x10^-5 per °C under ISO 11359-2: left out because the exponent format could not be matched to the source text by verify-values. The PX9406P CTE row is kept.'
sources:
  wikipedia-ppo:
    title: Polyphenylene oxide, Wikipedia
    id: Polyphenylene oxide article, introduction, history, manufacturers sections
    url: https://en.wikipedia.org/wiki/Polyphenylene_oxide
    kind: web
    license: CC BY-SA 4.0, linked not reproduced
  plabase-px9406p:
    title: NORYL PX9406P, SABIC SHPP Japan datasheet listing on PlaBase
    id: PlaBase item 5ebc224543428b0a5418c2f6, Basic, Thermal, Mechanical, Electrical and Building Properties tables
    url: https://en.plabase.com/plastic/items/5ebc224543428b0a5418c2f6
    year: 2026
    kind: database
    license: database listing, linked not reproduced
  plabase-nhp9023:
    title: NORYL NHP9023, SABIC SHPP Japan datasheet listing on PlaBase
    id: PlaBase item 5ebc223f43428b0a5418b7e8, Basic, Thermal, Mechanical and Electrical Properties tables
    url: https://en.plabase.com/plastic/items/5ebc223f43428b0a5418b7e8
    year: 2026
    kind: database
    license: database listing, linked not reproduced
  polysciences-08794:
    title: Poly(2,6-dimethyl-1,4-phenylene oxide), Polysciences product 08794
    id: Product page, specification table and safety and hazards field
    url: https://www.polysciences.com/default/poly26-dimethyl-14-phenylene-oxide
    year: 2026
    kind: datasheet
    license: supplier product page, linked not reproduced
  mhlw-ghs-25134-01-4:
    title: Japan GHS safety data sheet, Poly(2,6-dimethyl-1,4-phenylene oxide), CAS 25134-01-4
    id: Japan National Institute of Occupational Safety and Health GHS SDS record, product code R02-B-106
    url: https://anzeninfo.mhlw.go.jp/anzen/gmsds/25134-01-4.html
    year: 2021
    kind: database
    license: government database, linked not reproduced
  cfr-177-2460:
    title: 21 CFR 177.2460, Poly(2,6-dimethyl-1,4-phenylene) oxide resins
    id: US Code of Federal Regulations, Title 21, section 177.2460
    url: https://www.law.cornell.edu/cfr/text/21/177.2460
    year: 2026
    kind: standard
    license: US government regulation
  nist-atomic-weights-c:
    title: NIST Atomic Weights and Isotopic Compositions, carbon
    id: 'Standard atomic weight C: [12.0096, 12.0116]'
    url: https://physics.nist.gov/cgi-bin/Compositions/stand_alone.pl?ele=C&all=all&ascii=html
    kind: database
    license: US government data
  nist-atomic-weights-h:
    title: NIST Atomic Weights and Isotopic Compositions, hydrogen
    id: 'Standard atomic weight H: [1.007 84, 1.008 11]'
    url: https://physics.nist.gov/cgi-bin/Compositions/stand_alone.pl?ele=H&all=all&ascii=html
    kind: database
    license: US government data
  nist-atomic-weights-o:
    title: NIST Atomic Weights and Isotopic Compositions, oxygen
    id: 'Standard atomic weight O: [15.999 03, 15.999 77]'
    url: https://physics.nist.gov/cgi-bin/Compositions/stand_alone.pl?ele=O&all=all&ascii=html
    kind: database
    license: US government data
license: CC-BY-4.0
updated: '2026-10-26'
review:
  status: draft
  method: assistant
  checked_values: 20
  unreachable: 3
  caveats: 5
  note: 'Values were read by an AI assistant on 2026-10-26 from the pages named in each entry. The Noryl values are for PPE/PS blends from SABIC SHPP Japan, not for neat PPO. The only neat PPO property values are from one supplier powder. Unreachable: UL Prospector, SpecialChem and PubChem. The Gund outgassing bulletin was read and has no PPO row.'
story:
  recipe:
    line: PPO is made by oxidative coupling of 2,6-xylenol (21 CFR 177.2460). The repeat unit is (C8H8O)n, a dimethyl-substituted benzene ring linked to the next ring through an oxygen. Noryl grades are blends of PPE with polystyrene, which makes the resin easier to process.
    parts:
      - name: Carbon
        symbol: C
        role: Eight carbons per repeat unit, six in the benzene ring and two in the methyl groups.
        share_note: standard atomic weight [12.0096, 12.0116]
      - name: Hydrogen
        symbol: H
        role: Eight hydrogens per repeat unit, two aromatic and six from the methyl groups.
        share_note: standard atomic weight [1.007 84, 1.008 11]
      - name: Oxygen
        symbol: O
        role: One ether oxygen linking neighbouring rings.
        share_note: standard atomic weight [15.999 03, 15.999 77]
  risk_groups:
    - title: For people
      lead: The Japanese GHS entry for the neat resin gives a Warning signal word and respiratory hazards from dust.
      level: 2
      verdict: Warning, respiratory irritation
      points:
        - label: Classification
          line: The GHS entry prints the signal word Warning and states that the material may cause respiratory irritation and respiratory damage with repeated exposure.
        - label: Dust
          line: The entry says to avoid breathing dust and to use the material outdoors or in a well-ventilated area.
    - title: If it fails
      lead: The main failure route in these sources is loss of stiffness under sustained heat and load.
      points:
        - label: Softening under load
          line: The PX9406P heat deflection temperature is 122 °C at 1.82 MPa and 136 °C at 0.45 MPa, so stiffness falls well below the 150 °C Vicat point under load.
  why: PPO is an amorphous high-temperature thermoplastic that is almost always used in blends. The glass-fibre Noryl grade NHP9023 reaches 154 °C at 1.82 MPa and has a 5200 MPa flexural modulus. The unfilled PX9406P has a 1.1 g/cm3 density and absorbs 0.07 % water in 24 hours.
  can_do:
    - label: Stay stiff when warm
      value: 154 °C HDT at 1.82 MPa
      benchmark: heat_deflection_temperature
      line: NHP9023, a 15 % glass-fibre PPE/PS blend, reaches 154 °C at 1.82 MPa under ASTM D648, with no annealing.
    - label: Low water uptake
      value: 0.07 % in 24 hours
      benchmark: moisture_absorption
      line: PX9406P absorbs 0.07 % water in 24 hours under ASTM D570 at 23 °C.
  compare: These rows are for different products. The Noryl values are PPE/PS blends and the density and Tg of the neat powder are from a different supplier. They are examples and not a ranking.
  compare_rows:
    - scope: material
      label: Density
      benchmark: density
    - scope: material
      label: Heat deflection temperature
      benchmark: heat_deflection_temperature
    - scope: material
      label: Moisture absorption
      benchmark: moisture_absorption
  handling:
    - Specify the grade, since the neat resin, the unfilled PPE/PS blend and the 15 % glass-fibre grade differ in density, stiffness and heat deflection.
    - Avoid breathing dust, keep containers closed and work outdoors or in a well-ventilated area, as the GHS entry requires.
    - Treat the values as typical nominal values from datasheet listings, not as design minimums.
  good_for:
    - 'Stiff electrical and office-equipment parts that run warm: 154 °C HDT at 1.82 MPa for the 15 % glass-fibre Noryl grade NHP9023.'
    - 'Parts where low water uptake matters: 0.07 % in 24 hours for the unfilled Noryl PX9406P.'
  watch_out:
    - 'Ductility: elongation at break is 8 % for the unfilled PX9406P and 2.7 % for the glass-fibre NHP9023, so the glass-fibre grade is brittle.'
    - 'Short-term heat data only: the HDT values are load tests, and no long-term heat ageing was read.'
    - 'Space behaviour unknown: no atomic-oxygen, UV, outgassing or radiation data for PPO was found in the sources read.'
  verdict: PPO is an amorphous thermoplastic that is used mainly as a polystyrene blend. The Noryl grades read are stiff up to about 150 °C under load and absorb little water. The neat resin properties are from a single powder listing, and no sourced space-environment data was found.