Nomex aramid honeycomb core (Hexcel HexWeb HRH-10) HRH-10

spore: profile
id: nomex-honeycomb-hrh-10
spore_version: 0.2
family: glass-and-composites
name: Nomex aramid honeycomb core (Hexcel HexWeb HRH-10)
abbreviation: HRH-10
role: non-metallic sandwich core
category: composites
type: honeycomb-sandwich
summary: |
  Hexcel HexWeb HRH-10 is a honeycomb core made from NOMEX aramid paper dipped in phenolic resin. In a 3/16 inch cell at a nominal 3.0 lb/ft3 (pcf), Hexcel's product data sheet prints a typical bare compressive strength of 300 psi and a typical L-direction plate shear strength of 175 psi, both tested to AMS-STD-401 at 0.500 inch thickness. Hexcel recommends the core for service up to 350 °F, and its datasheet says the NOMEX softens between 450 °F and 500 °F. The core takes up moisture: the Hexcel brochure reports 4.4 % pickup in a 120-hour test at 95 % relative humidity and 120 °F.
best_for: Lightweight, fire-resistant sandwich panels for aircraft interiors and exterior parts such as radomes and fairings, where a low dielectric constant (1.11 at 9375 MHz) is also wanted (Hexcel)
weakest_at: Moisture uptake (4.4 % in the Hexcel 120-hour humidity test) and a long-term service limit of 350 °F; no vacuum, radiation or atomic-oxygen data found for space use
identity:
  formula: Nomex meta-aramid paper (a condensation product of m-phenylenediamine and isophthaloyl chloride) with a cured phenolic resin; a composite, so it has no single molecular formula
  source: wikipedia-nomex
  where: 'Nomex article: chemistry (meta-aramid, monomers m-phenylenediamine and isophthaloyl chloride) and phenolic resin use in honeycomb; the HRH-10 description is in hexcel-hrh10-datasheet, page 1'
tags:
  environments: []
  stresses:
    - extreme-heat
  applications:
    - structures
properties:
  - benchmark: density
    label: Density, HexWeb HRH-10 3/16 - 3.0 product
    value: 0.0481
    unit: g/cc
    scope: material
    conditions:
      product: HexWeb HRH-10 - 3/16 - 3.0
      basis: density printed for the 3/16 - 3.0 product on the LookPolymers listing
      test_conditions: none stated on the page
    method: Value printed in a reseller listing that reproduces the Hexcel product data (metric column)
    status: ground
    source: lookpolymers-hrh10
    where: Physical Properties table, Density row, metric column
  - benchmark: density
    label: Nominal density (designation), 3.0 pcf
    value: 3
    unit: lb/ft3
    scope: material
    conditions:
      basis: nominal density; the number in the designation HRH-10 - 3/16 - 3.0
      unit_in_source: pounds per cubic foot
    method: Printed in the Hexcel designation key; the datasheet uses the same designation
    status: ground
    source: hexcel-honeycomb-attributes
    where: Honeycomb Materials, HRH-10 section, designation key (page 10)
  - benchmark: compressive_strength_bare
    label: Compressive strength, bare, typical
    value: 300
    unit: psi
    scope: material
    conditions:
      product: HRH-10 - 3/16 - 3.0
      statistic: typical (mean of many blocks)
      condition: bare (not stabilized)
      test: AMS-STD-401 at 0.500 inch core thickness
      test_temperature: not printed in the table
    method: Compressive test per AMS-STD-401 as printed in the Hexcel product data sheet; the LookPolymers listing prints the same value as 2.07 MPa
    status: ground
    source: hexcel-hrh10-datasheet
    where: Mechanical Properties table (page 4), row HRH-10 - 3/16 - 3.0, Compressive Bare Strength typ
  - benchmark: compressive_strength_bare
    label: Compressive strength, bare, minimum
    value: 235
    unit: psi
    scope: material
    conditions:
      product: HRH-10 - 3/16 - 3.0
      statistic: minimum (recommended minimum average specification value)
      condition: bare (not stabilized)
      test: AMS-STD-401 at 0.500 inch core thickness
    method: Minimum value as printed in the Hexcel product data sheet; the LookPolymers listing prints 1.62 MPa as the bare minimum for the product line
    status: ground
    source: hexcel-hrh10-datasheet
    where: Mechanical Properties table (page 4), row HRH-10 - 3/16 - 3.0, Compressive Bare Strength min
  - benchmark: compressive_strength_stabilized
    label: Compressive strength, stabilized, typical
    value: 325
    unit: psi
    scope: material
    conditions:
      product: HRH-10 - 3/16 - 3.0
      statistic: typical (mean of many blocks)
      condition: stabilized (flatwise compressive strength, cell edges stabilized)
      test: AMS-STD-401 at 0.500 inch core thickness
    method: Compressive test per AMS-STD-401 as printed in the Hexcel product data sheet; the LookPolymers listing prints 2.24 MPa for the same statistic
    status: ground
    source: hexcel-hrh10-datasheet
    where: Mechanical Properties table (page 4), row HRH-10 - 3/16 - 3.0, Compressive Stabilized Strength typ
  - benchmark: compressive_strength_stabilized
    label: Compressive strength, stabilized, minimum
    value: 270
    unit: psi
    scope: material
    conditions:
      product: HRH-10 - 3/16 - 3.0
      statistic: minimum (recommended minimum average specification value)
      condition: stabilized
      test: AMS-STD-401 at 0.500 inch core thickness
    method: Minimum value as printed in the Hexcel product data sheet
    status: ground
    source: hexcel-hrh10-datasheet
    where: Mechanical Properties table (page 4), row HRH-10 - 3/16 - 3.0, Compressive Stabilized Strength min
  - benchmark: compressive_modulus_stabilized
    label: Compressive modulus, stabilized, typical
    value: 20
    unit: ksi
    scope: material
    conditions:
      product: HRH-10 - 3/16 - 3.0
      statistic: typical
      condition: stabilized
      test: AMS-STD-401 at 0.500 inch core thickness
    method: Typical value as printed in the Hexcel product data sheet; the LookPolymers listing prints 0.138 GPa (20.0 ksi)
    status: ground
    source: hexcel-hrh10-datasheet
    where: Mechanical Properties table (page 4), row HRH-10 - 3/16 - 3.0, Compressive Stabilized Modulus typ
  - benchmark: plate_shear_strength_L
    label: Plate shear strength, L direction, typical
    value: 175
    unit: psi
    scope: material
    conditions:
      product: HRH-10 - 3/16 - 3.0
      statistic: typical
      direction: L (ribbon) direction
      test: AMS-STD-401 at 0.500 inch core thickness
    method: Typical value as printed in the Hexcel product data sheet; the LookPolymers listing prints 1.21 MPa (175 psi)
    status: ground
    source: hexcel-hrh10-datasheet
    where: Mechanical Properties table (page 4), row HRH-10 - 3/16 - 3.0, Plate Shear L Direction Strength typ
  - benchmark: plate_shear_strength_L
    label: Plate shear strength, L direction, minimum
    value: 140
    unit: psi
    scope: material
    conditions:
      product: HRH-10 - 3/16 - 3.0
      statistic: minimum (recommended minimum average specification value)
      direction: L (ribbon) direction
      test: AMS-STD-401 at 0.500 inch core thickness
    method: Minimum value as printed in the Hexcel product data sheet; the LookPolymers listing prints 0.965 MPa (140 psi)
    status: ground
    source: hexcel-hrh10-datasheet
    where: Mechanical Properties table (page 4), row HRH-10 - 3/16 - 3.0, Plate Shear L Direction Strength min
  - benchmark: plate_shear_modulus_L
    label: Plate shear modulus, L direction, typical
    value: 6.5
    unit: ksi
    scope: material
    conditions:
      product: HRH-10 - 3/16 - 3.0
      statistic: typical
      direction: L (ribbon) direction
      test: AMS-STD-401 at 0.500 inch core thickness
    method: Typical value as printed in the Hexcel product data sheet; the LookPolymers listing prints 0.0448 GPa (6.50 ksi)
    status: ground
    source: hexcel-hrh10-datasheet
    where: Mechanical Properties table (page 4), row HRH-10 - 3/16 - 3.0, Plate Shear L Direction Modulus typ
  - benchmark: plate_shear_strength_W
    label: Plate shear strength, W direction, typical
    value: 100
    unit: psi
    scope: material
    conditions:
      product: HRH-10 - 3/16 - 3.0
      statistic: typical
      direction: W (expansion) direction
      test: AMS-STD-401 at 0.500 inch core thickness
    method: Typical value as printed in the Hexcel product data sheet; the LookPolymers listing prints 0.689 MPa (100 psi)
    status: ground
    source: hexcel-hrh10-datasheet
    where: Mechanical Properties table (page 4), row HRH-10 - 3/16 - 3.0, Plate Shear W Direction Strength typ
  - benchmark: plate_shear_strength_W
    label: Plate shear strength, W direction, minimum
    value: 85
    unit: psi
    scope: material
    conditions:
      product: HRH-10 - 3/16 - 3.0
      statistic: minimum (recommended minimum average specification value)
      direction: W (expansion) direction
      test: AMS-STD-401 at 0.500 inch core thickness
    method: Minimum value as printed in the Hexcel product data sheet; the LookPolymers listing prints 0.586 MPa (85.0 psi)
    status: ground
    source: hexcel-hrh10-datasheet
    where: Mechanical Properties table (page 4), row HRH-10 - 3/16 - 3.0, Plate Shear W Direction Strength min
  - benchmark: plate_shear_modulus_W
    label: Plate shear modulus, W direction, typical
    value: 3.4
    unit: ksi
    scope: material
    conditions:
      product: HRH-10 - 3/16 - 3.0
      statistic: typical
      direction: W (expansion) direction
      test: AMS-STD-401 at 0.500 inch core thickness
    method: Typical value as printed in the Hexcel product data sheet; the LookPolymers listing prints 0.0234 GPa (3.40 ksi)
    status: ground
    source: hexcel-hrh10-datasheet
    where: Mechanical Properties table (page 4), row HRH-10 - 3/16 - 3.0, Plate Shear W Direction Modulus typ
  - benchmark: cte
    label: Coefficient of thermal expansion, thickness direction (HRH-10 and HRH-310)
    value: 19.4
    unit: x10^-6 in/in-°F
    scope: material
    conditions:
      basis: thickness-direction coefficient printed for HRH-10 and HRH-310 together; the table does not name a cell size or density
      unit_in_source: inch/inch-°F, printed as 19.4 x 10-6
    method: Value printed in the Hexcel table of thermal expansion by core type; Space Mushroom did not convert it, so the value is in the printed unit
    status: ground
    source: hexcel-honeycomb-attributes
    where: Additional Mechanical Properties, Coefficient of Thermal Expansion table (page 18)
  - benchmark: moisture_absorption
    label: Moisture pickup, HRH-10 3/16 - 4.0 product
    value: 4.4
    unit: '%'
    scope: material
    conditions:
      product: HRH-10 - 3/16 - 4.0 (the 4.0 pcf row, not the 3.0 row)
      humidity: 95 % relative humidity
      temperature: 120 °F
      exposure: 120 hours
    method: Moisture pickup measured by Hexcel in the exposure described on the page
    status: ground
    source: hexcel-honeycomb-attributes
    where: Additional Mechanical Properties, Moisture Absorption (page 18), HRH-10 - 3/16 - 4.0 row
  - benchmark: max_service_temp
    label: Maximum long-term temperature, HRH-10
    value: 350
    unit: °F
    scope: material
    conditions:
      basis: maximum long-term temperature, as printed for HRH-10 in the attribute table; the same page recommends service up to 350 °F
      unit_in_source: °F
    method: Value printed by Hexcel in its attribute table and product description
    status: ground
    source: hexcel-honeycomb-attributes
    where: Attributes table (page 21), Maximum Long-Term Temperature row, HRH-10 column; Honeycomb Materials, HRH-10 description (page 10)
  - benchmark: strength_retention_temp
    label: Upper temperature for good strength retention, HRH-10 (Flex-Core data sheet)
    value: 300
    unit: °F
    scope: material
    conditions:
      basis: 'product description: good retention of strength up to this temperature; the same family of Hexcel data sheets gives 350 °F for the service limit'
      unit_in_source: °F
    method: Value printed in the Hexcel Nonmetallic Flex-Core data sheet product description
    status: ground
    note: The 300 °F figure differs from the 350 °F recommended service temperature printed in the other Hexcel documents; both are kept side by side.
    source: hexcel-flexcore-datasheet
    where: Product description, first page (HexWeb HRH-10 entry)
  - benchmark: softening_temperature
    label: Temperature range where NOMEX softens
    value: 450
    value_high: 500
    bound: range
    unit: °F
    scope: material
    conditions:
      basis: statement that NOMEX softens between these two temperatures; properties drop off rapidly there and most strength is retained after return to ambient
      test: shear and compressive tests at elevated temperatures for time exposures up to 500 hours
    method: Range printed in the Hexcel HRH-10 product data sheet, elevated-temperature section
    status: ground
    note: This is a softening range for the NOMEX polymer as Hexcel states it, not a service limit; the service limit is 350 °F.
    source: hexcel-hrh10-datasheet
    where: Additional Properties, Properties at Elevated Temperatures (page 5)
  - benchmark: dielectric_constant
    label: Dielectric constant, HRH-10 core density 3.0
    value: 1.11
    unit: '-'
    scope: material
    conditions:
      frequency: 9375 MHz
      polarization: electric field parallel to L (polarization parallel to L)
      core_density: 3.0 (printed without a unit)
      basis: representative production material
    method: Measured at 9375 MHz by Hexcel, per the table in the product data sheet
    status: ground
    source: hexcel-hrh10-datasheet
    where: Additional Properties, Dielectric Constant table (page 5), core density 3.0, E Parallel L column under Polarization Parallel to L
corrosion:
  - environment: Humid air, 95 % relative humidity at 120 °F for 120 hours
    headline: The core took up 4.4 % moisture in the Hexcel humidity test, the largest ageing concern printed for this product.
    effect: Hexcel exposed HRH-10 samples to 95 % relative humidity at 120 °F for 120 hours and measured 4.4 % moisture pickup for the 3/16 inch, 4.0 pcf row. The brochure does not give the moisture effect on strength, and no drying or recovery test was found.
    rating: moderate
    conditions:
      exposure: 95 % relative humidity, 120 °F, 120 hours
      product: HRH-10 - 3/16 - 4.0
    source: hexcel-honeycomb-attributes
    where: Additional Mechanical Properties, Moisture Absorption (page 18)
  - environment: Water, migration test
    headline: Water migration between cells is limited to one cell in 24 hours under the AMS STD-410 test.
    effect: The Hexcel datasheet says HRH-10 does not exceed one cell water migration in 24 hours when tested per AMS STD-410, and lists water and fungus resistance among its features. These are Hexcel statements; the datasheet gives no further numbers for water exposure.
    rating: low
    conditions:
      test: AMS STD-410 water migration test
      basis: Hexcel statement
    source: hexcel-hrh10-datasheet
    where: Specifications section (page 3), Water Migration; Features (page 1)
  - environment: Elevated temperature, strength after exposure
    headline: NOMEX softens between 450 °F and 500 °F, and strength drops off quickly there, though most of it returns on cooling.
    effect: The Hexcel datasheet says shear and compressive strength were tested at elevated temperatures for exposures up to 500 hours. Because the NOMEX softens between 450 °F and 500 °F, properties drop off rapidly at those temperatures; when the core returns to ambient conditions, most of the original strength is retained. No numbers are given for the elevated-temperature tests.
    rating: moderate
    conditions:
      temperature: 450 °F to 500 °F (softening range)
      exposure: up to 500 hours
      basis: datasheet statement, figures not printed as numbers
    source: hexcel-hrh10-datasheet
    where: Additional Properties, Properties at Elevated Temperatures (page 5)
  - environment: General corrosive attack (rating only)
    headline: Hexcel rates HRH-10 Excellent for corrosion resistance and Good for moisture resistance; these are ratings, not test numbers.
    effect: The attribute table rates HRH-10 Excellent for corrosion resistance, and Good for moisture resistance, on a scale of Excellent, Good, Fair, Poor. The table names no corrosive agent or test.
    rating: low
    conditions:
      basis: Hexcel rating scale; no environment or test named
    source: hexcel-honeycomb-attributes
    where: Attributes table (page 21), Corrosion Resistance and Moisture Resistance rows, HRH-10 column
risks:
  hazards:
    - text: Hexcel states that HexWeb HRH-10 will meet the 'self extinguishing' classification of FAA Air Crash Worthiness Rules and Regulations Section 25.853. This is a fire-behaviour statement from the manufacturer, not a GHS hazard class.
      ghs: []
      source: hexcel-hrh10-datasheet
      where: Specifications, Flame Retardance (page 3 of the US data sheet)
    - text: 'Precursor only, not the finished core: PubChem''s ECHA aggregate for m-phenylenediamine, one of the two monomers of the Nomex polymer, is built from 343 company reports and lists Toxic if swallowed (H301), Toxic in contact with skin (H311), Toxic if inhaled (H331), May cause an allergic skin reaction (H317), Causes serious eye irritation (H319), Suspected of causing genetic defects (H341), Very toxic to aquatic life (H400) and Very toxic to aquatic life with long lasting effects (H410), with signal word Danger.'
      ghs:
        - H301
        - H311
        - H331
        - H317
        - H319
        - H341
        - H400
        - H410
      source: pubchem-mphenylenediamine
      where: Safety and Hazards, GHS Classification, ECHA C&L aggregated entry (CID 7935)
  failure_risks:
    - mode: Moisture uptake in a humid environment
      trigger: Exposure to 95 % relative humidity at 120 °F for 120 hours (3/16 inch, 4.0 pcf product)
      consequence: 4.4 % moisture pickup by weight, printed by Hexcel; the brochure does not print the effect on compressive or shear strength.
      severity: moderate
      source: hexcel-honeycomb-attributes
      where: Additional Mechanical Properties, Moisture Absorption (page 18)
    - mode: Softening of the NOMEX above the service limit
      trigger: Exposure above the 350 °F recommended long-term service temperature, approaching the 450 °F to 500 °F softening range
      consequence: Properties drop off rapidly at the softening range; most strength is retained after return to ambient conditions, according to Hexcel.
      severity: moderate
      source: hexcel-hrh10-datasheet
      where: Additional Properties, Properties at Elevated Temperatures (page 5)
  side_effects: []
  handling:
    - text: Hexcel can machine the core to flat pieces cut to size, simple tapers, edge chamfers, double reliefs and complex or compound curvature, and can heat-form it on request.
      source: hexcel-hrh10-datasheet
      where: Special Configuration and Shapes (page 2)
    - text: Hexcel describes HRH-10 as damage resistant under normal shop use and formable.
      source: hexcel-hrh10-datasheet
      where: Features (page 1)
  mitigations: []
uses:
  - application: structures
    device: Commercial jet interior panels
    example: Hexcel says most interior panels of commercial jets, including the 737, 747, 777, 767, 787, A320, A350 and A380, are made with this core, mainly for its resilience, small cell size and low density combination, and its fire resistance.
    source: hexcel-hrh10-datasheet
    where: Applications (page 1)
  - application: structures
    device: Exterior aircraft parts, including radomes and fairings
    example: 'Hexcel says exterior aircraft parts such as radomes, fairings, helicopter blades and flaps are designed with HRH-10 for the same features: toughness, small cell size, low density and fire resistance.'
    source: hexcel-hrh10-datasheet
    where: Applications (page 1)
  - application: structures
    device: Surfboards and high-performance boats
    example: Knowde's listing of HexWeb HRH-10 gives surfboards and high-performance boats as two further uses, citing the core's toughness and its resistance to corrosive attack. The listing is a reseller page, not a Hexcel data sheet.
    source: knowde-hexweb-hrh10
    where: Applications section of the product page
supply:
  - subject: HexWeb HRH-10 finished honeycomb
    producers: []
    critical_lists: []
    recycling: Not stated in the Hexcel datasheets.
    substitutes:
      - Hexcel's HRH-310 uses the same aramid paper with a polyimide resin and is described by the brochure as having relatively low dielectric and loss tangent properties (a different core, not a substitute in the data).
    source: hexcel-hrh10-datasheet
    where: 'Availability (page 2): shipping terms FCA Hexcel, Casa Grande, AZ, USA (Incoterms 2010), with material title transfer at Hexcel, Casa Grande. No production share by country is printed in any source held.'
  - subject: HexWeb HRH-10 finished honeycomb, shipping points (EU data sheet)
    producers: []
    critical_lists: []
    recycling: Not stated in the Hexcel datasheets.
    substitutes: []
    source: hexcel-hrh10-eu-datasheet
    where: 'Availability (page 3): HexWeb HRH-10 will be shipped from Duxford, UK or Casa Grande, Arizona, USA. The data sheet names shipping points only; it does not give production shares.'
  - subject: NOMEX meta-aramid paper (feedstock for the cell walls)
    producers: []
    critical_lists: []
    recycling: Not stated in any source held.
    substitutes: []
    source: wikipedia-nomex
    where: 'Nomex article: developed by DuPont and first marketed in 1967; produced by condensation reaction from the monomers m-phenylenediamine and isophthaloyl chloride. The article names no current producer and gives no production share.'
media: []
documents:
  - title: HexWeb HRH-10 Aramid Fiber/Phenolic Resin Honeycomb, Product Data Sheet (Hexcel)
    type: datasheet
    url: https://hexcel.com/wp-content/uploads/2026/01/HexWeb_HRH10_DataSheet_us.pdf
    year: 2017
  - title: HexWeb Honeycomb Attributes and Properties (Hexcel brochure)
    type: datasheet
    url: https://www.hexcel.com/wp-content/uploads/2026/01/HexWebHoneycombAttributesandProperties.pdf
    year: 2016
  - title: HexWeb Nonmetallic Flex-Core Data Sheet (Hexcel)
    type: datasheet
    url: https://hexcel.com/wp-content/uploads/2025/12/HexWeb_NonmetallicFlexCore_DataSheet_us.pdf
    year: 2020
  - title: HexWeb HRH10 Data Sheet, EU version (Hexcel)
    type: datasheet
    url: https://hexcel.com/wp-content/uploads/2025/12/HexWeb_HRH10_DataSheet_eu1.pdf
    year: 2017
  - title: m-Phenylenediamine, PubChem compound record CID 7935 (GHS classification, ECHA C&L aggregate)
    type: database
    url: https://pubchem.ncbi.nlm.nih.gov/compound/7935
  - title: HexWeb HRH-10 product page (Knowde reseller listing)
    type: datasheet
    url: https://www.knowde.com/stores/hexcel/products/hexweb-hrh-10
gaps:
  - 'No space data for this core: no vacuum outgassing, atomic-oxygen, UV, radiation or thermal-vacuum result was found in any source held; the uses listed are aircraft applications only.'
  - No safety data sheet or GHS classification for the finished HexWeb HRH-10 honeycomb was found in any source held. The PubChem record for the poly(m-phenylene isophthalamide) polymer could not be found by name or by CAS number (24938-60-5). The only GHS data used is for the precursor monomer m-phenylenediamine (PubChem CID 7935), which is listed as a hazard for that raw chemical only, not for the honeycomb. A Hexcel SDS for HRH-10 was not found in the search and fetch of this run.
  - 'Standards: the hexagonal HRH-10 datasheet says it meets SAE AMS-3711 and AMS-81986 (page 3). The Flex-Core datasheet says HRH-10 Flex-Core meets SAE AMS3713 (density tolerance section). AMS3713 was not confirmed for the hexagonal product, so it is not stated as a specification for this profile. The AMS3713 text itself was not read.'
  - Thermal conductivity for HRH-10 is shown only as a chart in the datasheet (page 5); no number could be read from it, so no value is listed.
  - Dielectric constant is listed for core density 3.0 only, with the L-direction polarization; the other rows and the loss tangent were not carried over.
  - Elevated-temperature strength is described in the datasheet as figures only; no numeric values were read, so no strength-at-temperature property is listed.
  - Only the 3/16 inch cell at 3.0 pcf is profiled for strength and density. The other cell sizes and densities in the Hexcel tables (for example 1/8 - 3.0 and 3/16 - 4.0) are not carried here. Moisture pickup is from the 3/16 - 4.0 row, which is the only moisture value printed.
  - Humidity ageing beyond one 120-hour test was not found; no strength result after moisture exposure and no UV or chemical-resistance number was found.
  - Composition percentages (resin content, paper grade or weight) were not found in any source held.
  - No CAS number or designation other than the Hexcel trade name HRH-10 was found for this grade. The AMS specifications listed above are compliance statements, not grade designations.
  - Density tolerance is plus or minus 10 % per the Hexcel datasheet; it is noted here but not stored as a property.
  - The 3/16 - 3.0 values come from Hexcel's own tables; the LookPolymers listing is a reseller page and was used only for the density and as a cross-check of the metric conversions.
  - The 300 °F strength-retention figure (Flex-Core datasheet) and the 350 °F service limit (brochure) disagree in their wording; both are kept side by side and neither is treated as the single correct value.
  - Cell-wall material is described by Wikipedia as meta-aramid; the 370 °C (700 °F) figure on that page applies to the Nomex fibre, not to the honeycomb, and is not used as a property here.
  - No open-access paper on Nomex honeycomb thermal ageing, moisture or compressive strength could be read in this run. The Nottingham repository record that a search returned (output 949587) gave HTTP 403 and was not used.
  - 'The comparison uses ratings only for the other brochure cores: aluminum CR III 5052 and HRH-327 (fiberglass polyimide). Their properties are not profiled here.'
  - No images or figures were added to this profile.
sources:
  hexcel-hrh10-datasheet:
    title: HexWeb HRH-10 Aramid Fiber/Phenolic Resin Honeycomb, Product Data Sheet
    id: Hexcel Corporation, copyright 2017
    url: https://hexcel.com/wp-content/uploads/2026/01/HexWeb_HRH10_DataSheet_us.pdf
    year: 2017
    kind: datasheet
    license: Hexcel copyright; cited, not reproduced
  hexcel-honeycomb-attributes:
    title: HexWeb Honeycomb Attributes and Properties (Hexcel brochure)
    id: Hexcel Corporation, copyright 2016
    url: https://www.hexcel.com/wp-content/uploads/2026/01/HexWebHoneycombAttributesandProperties.pdf
    year: 2016
    kind: datasheet
    license: Hexcel copyright; cited, not reproduced
  hexcel-flexcore-datasheet:
    title: HexWeb Nonmetallic Flex-Core Data Sheet
    id: Hexcel Corporation, copyright 2020 (US data sheet)
    url: https://hexcel.com/wp-content/uploads/2025/12/HexWeb_NonmetallicFlexCore_DataSheet_us.pdf
    year: 2020
    kind: datasheet
    license: Hexcel copyright; cited, not reproduced
  lookpolymers-hrh10:
    title: Hexcel HexWeb HRH-10 - 3/16 - 3.0 Aramid Fiber/Phenolic Resin Honeycomb (LookPolymers product page)
    id: LookPolymers product listing; reseller page reproducing Hexcel data
    url: https://www.lookpolymers.com/polymer_Hexcel-HexWeb-HRH-10-316-30-Aramid-FiberPhenolic-Resin-Honeycomb.php
    kind: web
    license: Reseller page, cited, not reproduced
  wikipedia-nomex:
    title: Nomex
    id: Wikipedia, English edition (chemistry and history only)
    url: https://en.wikipedia.org/wiki/Nomex
    kind: web
    license: CC BY-SA (Wikipedia)
  pubchem-mphenylenediamine:
    title: m-Phenylenediamine, PubChem compound record CID 7935 (Safety and Hazards, GHS Classification)
    id: PubChem, National Center for Biotechnology Information (ECHA C&L aggregated entry, 343 reports)
    url: https://pubchem.ncbi.nlm.nih.gov/compound/7935
    kind: database
    license: PubChem data, public domain (NCBI)
  knowde-hexweb-hrh10:
    title: HexWeb HRH-10 product page (Knowde reseller listing)
    id: Knowde Marketplace, Hexcel storefront
    url: https://www.knowde.com/stores/hexcel/products/hexweb-hrh-10
    kind: web
    license: Reseller page, cited, not reproduced
  hexcel-hrh10-eu-datasheet:
    title: HexWeb HRH10 Data Sheet, EU version
    id: Hexcel Corporation, copyright 2017
    url: https://hexcel.com/wp-content/uploads/2025/12/HexWeb_HRH10_DataSheet_eu1.pdf
    year: 2017
    kind: datasheet
    license: Hexcel copyright; cited, not reproduced
license: CC-BY-4.0
updated: '2026-11-01'
review:
  status: draft
  method: assistant
  checked_values: 19
  unreachable: 1
  caveats: 3
  note: Written by an AI assistant on 2026-11-01 from Hexcel data sheets (US and EU), a Hexcel brochure, a reseller listing, Wikipedia and the PubChem record for the m-phenylenediamine monomer; 19 property rows read from fetched pages. The PubChem record for the polymer itself could not be found. The hazards list holds the precursor monomer's GHS data and the Hexcel flame statement; no hazard data exists for the finished core in the sources held. The AMS3713 statement is a Flex-Core claim and is not stated for the hexagonal product.
story:
  recipe:
    line: Hexcel makes HexWeb HRH-10 from NOMEX aramid fibre sheets. A thermosetting adhesive bonds the sheets at the nodes, the block is expanded into the hexagonal or OX-Core cell shape, dipped in phenolic resin, cured, and sliced to thickness. The datasheet says this process gives a wide range of cell sizes, paper thicknesses and densities.
    parts:
      - name: NOMEX aramid paper
        role: Forms the cell walls. Wikipedia describes Nomex as meta-aramid chemistry, made from m-phenylenediamine and isophthaloyl chloride.
      - name: Thermosetting adhesive
        role: Bonds the aramid sheets at the nodes before the block is expanded into the cell shape.
      - name: Phenolic resin
        role: A heat-resistant resin dipped into the expanded block to reach the final density. The product is described as fire-resistant.
  risk_groups:
    - title: For people
      verdict: No hazard classification found
      lead: No GHS hazard classification was found for the finished honeycomb in any source we hold. The raw monomer m-phenylenediamine does carry one (see Precursor below).
      points:
        - label: Fire
          line: Hexcel says HRH-10 is fire-resistant and self-extinguishing, and that it meets the self-extinguishing classification of the FAA rules for aircraft crashworthiness.
        - label: Heat
          line: Hexcel recommends service up to 350 °F. Its datasheet says NOMEX softens between 450 °F and 500 °F, where properties drop off rapidly.
        - label: Moisture
          line: In a 120-hour test at 95 % relative humidity and 120 °F, the 4.0 pcf product took up 4.4 % moisture (Hexcel brochure).
        - label: Precursor
          line: PubChem's ECHA aggregate for m-phenylenediamine, a Nomex monomer, lists Toxic if swallowed (H301), Toxic in contact with skin (H311) and Toxic if inhaled (H331) at signal word Danger. This describes the raw chemical, not the finished core.
    - title: Handling and shaping
      points:
        - label: Shaping
          line: Hexcel can machine the core to complex curvature and can heat-form it on request.
        - label: Shop handling
          line: Hexcel describes the core as damage resistant under normal shop use.
    - title: Space use
      lead: No space data was found for this core.
      points:
        - label: Evidence
          line: We found no vacuum, outgassing, atomic-oxygen, UV or radiation test for this core in any source held.
  why: The Nomex aramid honeycomb core Hexcel HexWeb HRH-10 is a lightweight, non-metallic sandwich core made from NOMEX aramid paper dipped in phenolic resin. In a 3/16 inch cell at a nominal 3.0 pcf, its typical bare compressive strength is 300 psi, according to the Hexcel product data sheet. Hexcel uses it for aircraft interior panels and exterior parts such as radomes and fairings. Hexcel says the Flex-Core version of HRH-10 meets AMS3713, but the hexagonal product datasheet lists AMS-3711 and AMS-81986 instead. This profile is about the honeycomb core, not the Nomex fibre and paper.
  uses:
    - where: Commercial jet interiors
      line: Hexcel says most interior panels of commercial jets, including the 737, 747, 777, 767, 787, A320, A350 and A380, are made with this core, mainly for its resilience, small cell size and low density, and for its fire resistance.
    - where: Exterior aircraft parts
      line: Hexcel lists radomes, fairings, helicopter blades and flaps as exterior parts designed with HRH-10.
    - where: Space
      line: No space application was found in the sources we hold.
  can_do:
    - label: Density
      benchmark: density
      value: 0.0481 g/cc
      line: The LookPolymers listing prints a density of 0.0481 g/cc for the HexWeb HRH-10 3/16 - 3.0 product.
    - label: Compressive strength
      benchmark: compressive_strength_bare
      value: 300 psi typical
      line: The Hexcel product data sheet prints a typical bare compressive strength of 300 psi and a minimum of 235 psi for the 3/16 inch, 3.0 pcf product, tested to AMS-STD-401 at 0.500 inch core thickness.
    - label: Shear strength
      benchmark: plate_shear_strength_L
      value: 175 psi typical
      line: In the L direction, the same datasheet row gives a typical plate shear strength of 175 psi and a minimum of 140 psi.
    - label: Temperature
      benchmark: max_service_temp
      value: 350 °F
      line: Hexcel's brochure gives a maximum long-term temperature of 350 °F for HRH-10 in its attribute table, page 21.
    - label: Moisture
      benchmark: moisture_absorption
      value: 4.4 %
      line: Hexcel's brochure reports 4.4 % moisture pickup after 120 hours at 95 % relative humidity and 120 °F for the 3/16 inch, 4.0 pcf product.
    - label: Dielectric
      benchmark: dielectric_constant
      value: '1.11'
      line: At 9375 MHz and core density 3.0, the dielectric constant is 1.11 with the electric field parallel to L.
  compare: Against the other honeycomb types in the Hexcel brochure, HRH-10 is rated Excellent for flammability resistance, fatigue strength and corrosion resistance, and Good for moisture resistance. The aluminum CR III 5052 core is rated Excellent for moisture resistance and Good for corrosion resistance, but it has a High heat transfer rating against Low for HRH-10, and it costs less (Moderately Low relative cost against Medium for HRH-10). Both are listed at a maximum long-term temperature of 350 °F, while the fiberglass polyimide HRH-327 is rated 500 °F. The table gives ratings only, so these comparisons carry no test numbers.
  compare_rows:
    - label: Compressive strength, bare, typical
      benchmark: compressive_strength_bare
    - label: Plate shear strength, L direction, typical
      benchmark: plate_shear_strength_L
    - label: Maximum long-term temperature
      benchmark: max_service_temp
  handling:
    - Hexcel can machine and form the core on request, including flat pieces cut to size and complex curvature.
    - 'Keep the core dry where it can. Moisture is the main ageing concern in the data: 4.4 % pickup in the Hexcel humidity test.'
    - Do not hold the core above 350 °F for long periods; NOMEX softens between 450 °F and 500 °F.
    - No safety data sheet was found, so ask the supplier for one before handling bulk material.
  good_for:
    - Lightweight, fire-resistant sandwich panels such as aircraft interior panels and exterior parts (Hexcel).
    - 'Low dielectric constant structures: 1.11 at 9375 MHz for the 3.0 core density.'
  watch_out:
    - 'Moisture uptake: 4.4 % in the 120-hour humidity test on the 4.0 pcf product.'
    - Strength values are typical and minimum figures at 0.500 inch thickness, not design allowables.
    - No vacuum, radiation or atomic-oxygen data was found, so space use is unverified.
  verdict: HexWeb HRH-10 is an established, fire-resistant aramid honeycomb core for aircraft panels, with published strength, dielectric and moisture data from Hexcel. For a space application the record has no vacuum, radiation or atomic-oxygen data, and its moisture uptake is the open question.