spore: profile
id: dyneema-spectra-hmpe-fibre
spore_version: 0.2
family: polyolefins
name: Dyneema and Spectra HMPE fibre (ultra-high-strength polyethylene fibre)
abbreviation: HMPE
role: high-strength polyethylene fibre for tethers, lines, rope and ballistic products
category: polymers
type: polyolefins
summary: |
  Dyneema and Spectra are high-modulus polyethylene (HMPE) fibres, a gel-spun form of ultra-high-molecular-weight polyethylene (UHMWPE) with a molar mass of 2 to 6 million daltons. The MiniFIBERS datasheet for a Dyneema SK crimped staple prints a specific gravity of 0.975 and a tenacity of about 3.0 GPa, and recommends continuous use at 70 °C or lower. Wikipedia gives a density as low as 0.97 g/cm3 for Dyneema SK75 and yield strengths as high as 2.4 GPa for gel-spun fibres. The sources disagree on UV: the staple datasheet rates UV durability as excellent, while a 2022 barrier-net study found that UV ageing lowers breaking strength faster than salt spray.
best_for: Lightweight tethers, mooring lines and lifting slings where strength for weight matters, with a specific gravity of 0.975 and a tenacity of about 3.0 GPa for the staple
weakest_at: 'Heat and UV: a continuous use limit of 70 °C for the staple, and UV ageing that breaks polymer chains faster than salt spray in a 2022 barrier-net study'
identity:
  formula: (C2H4)n, ultra-high-molecular-weight polyethylene fibre
  source: wiki-uhmwpe
  where: Lead paragraph (HMPE name and molar mass of 2 to 6 million daltons). The formula is the polyethylene repeat unit; the sources read do not print it for the fibre.
  designations:
    - system: Trade name
      code: Dyneema
      source: wiki-uhmwpe
      where: Gel spinning section, sentence on Dyneema commercialised by DSM
    - system: Trade name
      code: Spectra
      source: wiki-uhmwpe
      where: Gel spinning section, sentence on Spectra commercialised by Honeywell
    - system: Trade name
      code: Dyneema® SK75
      source: dyneema-portfolio
      where: Lifting, lashing and rigging table, first row
    - system: Trade name
      code: Dyneema® SK78
      source: dyneema-portfolio
      where: Lifting, lashing and rigging table, SK78 row
    - system: Trade name
      code: Dyneema SK Crimped Staple
      source: dyneema-sk-staple-tds
      where: Document title, Dyneema SK Crimped Staple
tags:
  environments: []
  stresses:
    - extreme-heat
  applications:
    - structures
properties:
  - benchmark: density
    label: Specific gravity, Dyneema SK crimped staple (2.0 dpf)
    value: 0.975
    unit: g/cm3
    scope: material
    conditions:
      product: Dyneema SK Crimped Staple, product code prefix PEDYN-020NLH
      filament: 2.0 denier per filament
      test: not printed on the page
    method: Typical value printed on the MiniFIBERS datasheet, which says it describes typical values and is not a specification
    status: ground
    source: dyneema-sk-staple-tds
    where: Datasheet, Specific Gravity row
  - benchmark: ultimate_tensile_strength
    label: Tenacity, Dyneema SK crimped staple
    value: 3
    unit: GPa
    scope: material
    conditions:
      product: Dyneema SK Crimped Staple, 2.0 dpf
      printed_as: ~3.0 GPa (the same row also prints about 32 to 38 g/den)
    method: Typical value printed on the MiniFIBERS datasheet
    status: ground
    source: dyneema-sk-staple-tds
    where: Datasheet, Tenacity row
  - benchmark: elastic_modulus
    label: Modulus, Dyneema SK crimped staple
    value: 104
    unit: GPa
    scope: material
    conditions:
      product: Dyneema SK Crimped Staple, 2.0 dpf
      printed_as: ~104 GPa (the same row also prints 1127 to 1297 g/den)
    method: Typical value printed on the MiniFIBERS datasheet
    status: ground
    source: dyneema-sk-staple-tds
    where: Datasheet, Modulus row
  - benchmark: elongation
    label: Elongation, Dyneema SK crimped staple
    value: 4
    bound: upper
    unit: '%'
    scope: material
    conditions:
      product: Dyneema SK Crimped Staple, 2.0 dpf
      printed_as: <4.0%
    method: Typical value printed on the MiniFIBERS datasheet
    status: ground
    source: dyneema-sk-staple-tds
    where: Datasheet, Elongation row
  - benchmark: shrinkage_boiling_water
    label: Shrinkage in boiling water, Dyneema SK crimped staple
    value: 1
    bound: upper
    unit: '%'
    scope: material
    conditions:
      product: Dyneema SK Crimped Staple, 2.0 dpf
      printed_as: <1.0%
    method: Typical value printed on the MiniFIBERS datasheet; benchmark name is not in the property canon
    status: ground
    source: dyneema-sk-staple-tds
    where: Datasheet, Shrinkage Boiling Water row
  - benchmark: melting_point
    label: Melting range, Dyneema SK crimped staple
    value: 144
    value_high: 152
    unit: °C
    scope: material
    conditions:
      product: Dyneema SK Crimped Staple, 2.0 dpf
      printed_as: 144-152oC / 290-306oF
    method: Typical value printed on the MiniFIBERS datasheet, Effect of Heat paragraph
    status: ground
    source: dyneema-sk-staple-tds
    where: Datasheet, Effect of Heat row
  - benchmark: max_service_temp
    label: Recommended continuous use temperature, Dyneema SK crimped staple
    value: 70
    bound: upper
    unit: °C
    scope: material
    conditions:
      product: Dyneema SK Crimped Staple, 2.0 dpf
      printed_as: 70oC or lower
    method: Recommendation printed on the MiniFIBERS datasheet, Effect of Heat paragraph
    status: ground
    source: dyneema-sk-staple-tds
    where: Datasheet, Effect of Heat row
  - benchmark: decomposition_temperature
    label: Decomposition temperature, Dyneema SK crimped staple
    value: 300
    bound: lower
    unit: °C
    scope: material
    conditions:
      product: Dyneema SK Crimped Staple, 2.0 dpf
      printed_as: '>300oC / 572oF'
    method: Printed on the MiniFIBERS datasheet, Effect of Heat paragraph; benchmark name is not in the property canon
    status: ground
    source: dyneema-sk-staple-tds
    where: Datasheet, Effect of Heat row
  - benchmark: density
    label: Density, Dyneema SK75 gel-spun fibre (as low as)
    value: 0.97
    bound: lower
    unit: g/cm3
    scope: material
    conditions:
      grade: Dyneema SK75
      form: gel-spun fibre
      temperature: not stated
    method: Stated in a Wikipedia article (secondary source); the article says "as low as" for this grade
    status: ground
    source: wiki-uhmwpe
    where: Gel spinning section, density sentence (SK75 named in the same sentence)
  - benchmark: yield_strength
    label: Yield strength, gel-spun HMPE fibre (as high as)
    value: 2.4
    bound: upper
    unit: GPa
    scope: material
    conditions:
      form: gel-spun fibre (Dyneema or Spectra)
      grade: not named in this sentence
      basis: the article reports yield strength, not tensile strength
    method: Stated in a Wikipedia article (secondary source); the article says "as high as"
    status: ground
    note: This is a yield strength in a secondary article, not a datasheet tenacity; the staple datasheet reports tenacity in GPa.
    source: wiki-uhmwpe
    where: Gel spinning section, strength sentence
  - benchmark: molar_mass
    label: Molecular mass, UHMWPE (typical range as stated)
    value: 2
    value_high: 6
    unit: million daltons
    scope: material
    conditions:
      basis: general UHMWPE molecular mass as stated in the article; not a fibre test
    method: Stated in a Wikipedia article (secondary source); benchmark name is not in the property canon
    status: ground
    source: wiki-uhmwpe
    where: Lead paragraph
  - benchmark: melting_point
    label: Melting point, Marlow D12+ 75/78 rope (Dyneema SK75 or SK78 braid)
    value: 140
    unit: °C
    scope: material
    conditions:
      form: single braid rope, 12 x 1 construction
      material: Dyneema SK75 or SK78
    method: Printed on the Marlow Ropes datasheet, Key Specifications
    status: ground
    note: The rope sheet gives 140 °C, and the staple datasheet gives 144 to 152 °C. Both are recorded because they differ by form.
    source: marlow-d12
    where: Key Specifications, Melting Point row
  - benchmark: max_service_temp
    label: Critical temperature, Marlow D12+ 75/78 rope
    value: 80
    unit: °C
    scope: material
    conditions:
      form: single braid rope, Dyneema SK75 or SK78
      printed_as: 80°C (exposure to temperatures over this will result in permanent strength loss)
    method: Printed on the Marlow Ropes datasheet, Key Specifications
    status: ground
    source: marlow-d12
    where: Key Specifications, Critical Temperature row
  - benchmark: breaking_force
    label: Breaking force after salt spray ageing, UHMWPE fibre barrier net
    value: 655
    unit: 'N'
    scope: material
    conditions:
      specimen: UHMWPE fibre marine barrier net, salt spray aged
      ageing: salt spray, 60 days
      test: tensile test to Chinese standard GB/T 4925-2008, as the article states
    method: Measured in a 2022 laboratory study; benchmark name is not in the property canon
    status: ground
    source: mdpi-barrier-net
    where: Results, Figure 9a text (salt spray environment)
  - benchmark: breaking_force
    label: Breaking force after hygrothermal ageing, UHMWPE fibre barrier net (10 days)
    value: 703
    unit: 'N'
    scope: material
    conditions:
      specimen: UHMWPE fibre marine barrier net
      ageing: hygrothermal, 10 days
      test: tensile test to Chinese standard GB/T 4925-2008, as the article states
    method: Measured in a 2022 laboratory study; benchmark name is not in the property canon
    status: ground
    source: mdpi-barrier-net
    where: Results, Figure 9b text (hygrothermal environment)
  - benchmark: breaking_force
    label: Breaking force after hygrothermal ageing, UHMWPE fibre barrier net (30 days)
    value: 725
    unit: 'N'
    scope: material
    conditions:
      specimen: UHMWPE fibre marine barrier net
      ageing: hygrothermal, 30 days
      test: tensile test to Chinese standard GB/T 4925-2008, as the article states
    method: Measured in a 2022 laboratory study; benchmark name is not in the property canon
    status: ground
    source: mdpi-barrier-net
    where: Results, Figure 9b text (hygrothermal environment, after the slight increase)
corrosion:
  - environment: Sunlight and ultraviolet light
    headline: UV is the main ageing route in the sources, although the datasheets rate UV resistance highly.
    effect: The MiniFIBERS staple datasheet states excellent resistance to sunlight and UV degradation. The Marlow rope sheet rates UV resistance as very good. Wikipedia calls UV damage one notable drawback of UHMWPE rope. In a 2022 study of a UHMWPE fibre barrier net, the fibre showed obvious cracks and damage after UV irradiation, and the paper states that UV energy lowers breaking strength more efficiently than salt spray.
    rating: moderate
    conditions:
      basis: datasheet ratings and a laboratory UV lamp test (UVA-351 type 1A lamp) on a barrier net; no outdoor service test was read
    source: mdpi-barrier-net
    where: Section 2.2.1 (UV aging experiment), Results text on UV irradiation (Figure 5c text) and Figure 9 discussion
  - environment: Chemicals and solvents
    headline: The staple datasheet reports excellent chemical resistance, and only strong oxidisers are named as attackers.
    effect: The staple datasheet states excellent resistance to acids, alkalis, and most chemicals, and says only strong oxidizers are able to attack the mechanical properties. The Marlow rope sheet also rates chemical resistance as excellent to most chemicals.
    rating: low
    conditions:
      basis: datasheet statements; no test condition or chemical list is printed
    source: dyneema-sk-staple-tds
    where: Datasheet, Chemical Resistance row (Marlow rope sheet, Chemical Resistance row, second source)
  - environment: Hot air above the continuous use limit
    headline: Strength and modulus fall as temperature rises, with a continuous use limit of 70 °C for the staple.
    effect: The staple datasheet says strength and modulus decrease at higher temperatures and recommends continuous use at 70 °C or lower. The Marlow rope sheet gives a critical temperature of 80 °C, above which exposure results in permanent strength loss.
    rating: moderate
    conditions:
      basis: two datasheets, one for a staple (2.0 dpf) and one for a rope (Dyneema SK75 or SK78 braid); no test duration printed
    source: dyneema-sk-staple-tds
    where: Datasheet, Effect of Heat row (Marlow rope sheet, Critical Temperature row, second source)
risks:
  hazards:
    - text: The UHMWPE sheet-grade SDS (TIVAR VMX) prints GHS Classification None, Signal Word None and no hazard statements. This is a UHMWPE sheet SDS, not a Dyneema or Spectra fibre SDS, and no fibre SDS was read in this run.
      ghs: []
      source: tivar-vmx-sds
      where: Section 2, GHS Classification block
    - text: The same SDS states that dust is flammable and can form an explosive mixture with air when finely divided, and that the explosion hazard applies to dusts, not granular forms of the product.
      ghs: []
      source: tivar-vmx-sds
      where: Fire-fighting and handling text on dust hazards
  failure_risks:
    - mode: Heat-induced loss of strength
      trigger: Continuous use above 70 °C for the staple, or exposure above the 80 °C critical temperature for the rope
      consequence: Strength and modulus decrease at higher temperatures, and the rope loses strength permanently above its critical temperature.
      severity: high
      source: dyneema-sk-staple-tds
      where: Datasheet, Effect of Heat row (Marlow rope sheet, Critical Temperature row)
    - mode: UV chain breaking
      trigger: Long sunlight or UV exposure of an unprotected fibre
      consequence: In a 2022 barrier-net study, breaking strength fell faster under UV than under salt spray, and the fibre showed cracks after UV irradiation.
      severity: moderate
      source: mdpi-barrier-net
      where: Results text on UV ageing and Figure 5c text
    - mode: Creep under sustained load
      trigger: Load held for long periods at elevated temperature
      consequence: Creep is a factor of load, temperature and time, per the rope sheet, and the SK78 grade is described as offering improved creep performance.
      severity: moderate
      source: marlow-d12
      where: Product description and Creep row
  side_effects:
    - text: Will burn slowly if ignited in atmospheric conditions, and is qualified as self-extinguishing on removal of the flame.
      affects: Fire response near the fibre product
      source: dyneema-sk-staple-tds
      where: Datasheet, Effect of Heat row
  handling:
    - text: The staple datasheet says that in air the fibre is stable for many years.
      source: dyneema-sk-staple-tds
      where: Datasheet, Durability row
    - text: Keep the fibre below the continuous use limit given on the staple datasheet, which is 70 °C or lower.
      source: dyneema-sk-staple-tds
      where: Datasheet, Effect of Heat row
  mitigations:
    - text: Use the lower of the two heat limits in the sources read, since the rope sheet critical temperature of 80 °C is for a different form from the staple.
      source: marlow-d12
      where: Key Specifications, Critical Temperature row
uses:
  - application: structures
    device: Space tether
    example: UHMWPE was used for the 30 km (19 mi) long, 0.6 mm (0.024 in) thick space tether in the ESA/Russian Young Engineers' Satellite 2 of September, 2007.
    source: wiki-uhmwpe
    where: Uses section, space tether sentence (the article does not name the grade flown)
  - application: structures
    device: Mooring lines, sailing lines and engineered lifting slings
    example: Dyneema SK78 is listed for mooring lines, sailing lines, and general purpose and engineered lifting slings, with the printed property High strength, high safety and reliability. High fatigue, creep, abrasion and extreme temp. resistance.
    source: dyneema-portfolio
    where: Lifting, lashing and rigging table, SK78 row
  - application: structures
    device: Single-braid all-round rope
    example: Marlow D12+ is a single braid rope made from Dyneema SK75 or SK78, offered as a lightweight, high strength and flexible alternative to steel wire.
    source: marlow-d12
    where: Product description
supply:
  - subject: Ethylene (monomer for UHMWPE)
    demand: Worldwide production was over 225 million tonnes in 2022, per the Wikipedia Ethylene article.
    routes: Steam cracking, which heats hydrocarbons and steam to 750-950 °C, is a primary production method, per the same article.
    producers: []
    critical_lists: []
    substitutes: []
    source: wiki-ethylene
    where: Lead paragraph (world production) and Industrial process section
  - subject: Gel-spun HMPE fibre (Dyneema and Spectra)
    demand: Dyneema was commercialised in the late 1970s by the Dutch chemical company DSM, and Spectra by Honeywell (then AlliedSignal), per the Wikipedia UHMWPE article. The MiniFIBERS datasheet names Avient Protective Materials as the owner of the Dyneema trademark.
    routes: The fibres are gel-spun, described in the article as oriented-strand gels spun through a spinneret. No tonnage or share is printed in the sources read.
    producers: []
    critical_lists: []
    substitutes: []
    source: wiki-uhmwpe
    where: Gel spinning section (trade names); MiniFIBERS datasheet, trademark line
    abundance: 'Producers named in the sources, with no tonnages or country shares given: DSM (Dyneema), Honeywell (Spectra), Avient Protective Materials (Dyneema trademark).'
documents:
  - title: MiniFIBERS technical data sheet, Dyneema SK Crimped Staple
    type: datasheet
    url: https://www.minifibers.com/files/TD/PI-TDS_Dyneema-SK-Crimped-Staple.pdf
  - title: Dyneema product portfolio, fibre grades and uses
    type: datasheet
    url: https://www.dyneema.com/design-with-dyneema/dyneema-product-portfolio
  - title: Marlow Ropes D12+ 75/78 datasheet (Dyneema SK75 or SK78)
    type: datasheet
    url: https://shop.marlowropes.com/content/files/datasheets/defence/datasheets%20with%20iso%2014001/d12+%207578%202024.pdf
  - title: Study on the Aging Behavior of an Ultra-High Molecular Weight Polyethylene Fiber Barrier Net in a Marine Environment, Materials 2022, 15(16), 5599
    type: paper
    url: https://doi.org/10.3390/ma15165599
    year: 2022
  - title: TIVAR VMX food-grade UHMW-PE safety data sheet (UHMWPE sheet grade, not a fibre SDS)
    type: sds
    url: https://www.boedeker.com/Portals/0/Safety%20Data%20Sheets%20SDS/MCAM/MCAM-TIVAR-VMX-FOOD-GRADE-UHMW-EN-SDS-1609-211004-feb-2024.pdf
    year: 2024
gaps:
  - No safety data sheet for a Dyneema or Spectra fibre was read in this run; the hazard entries use the TIVAR VMX UHMWPE sheet-grade SDS and say so.
  - No outgassing, atomic oxygen, radiation or vacuum data for HMPE fibre was read in this run, so none is recorded.
  - Tensile strength of Dyneema SK75 filament in a datasheet was not read in this run; the tenacity recorded is from the staple datasheet, and the SK75 yield value is from the Wikipedia article.
  - UV breaking strength in newtons after UV exposure is not printed in the barrier-net text read; the UV evidence is qualitative and the numeric rows are salt spray and hygrothermal ageing only.
  - Melting onset of 127.7 °C and typical density, elongation and yield values in the Wikipedia article are for UHMWPE in general, not for this fibre, and are not recorded.
  - Marlow relative density of 0.97 is printed without a unit, so it is not recorded; the Wikipedia density of 0.97 g/cm3 for SK75 is recorded instead.
  - Non-canonical benchmark names are used for decomposition temperature, shrinkage in boiling water, molar mass and breaking force, because the property canon has no matching name.
  - No producer tonnages, country shares or critical-mineral listing were found for HMPE fibre or for ethylene by country.
  - Chemical resistance is recorded as datasheet statements only; no chemical list or test condition was read.
  - Cut-resistance and ballistic grade data on the Dyneema portfolio page are not recorded because they have no numeric value on the page read.
sources:
  dyneema-sk-staple-tds:
    title: MiniFIBERS technical data sheet, Dyneema SK Crimped Staple (product code prefix PEDYN-020NLH)
    id: PI-TDS Dyneema SK Crimped Staple
    url: https://www.minifibers.com/files/TD/PI-TDS_Dyneema-SK-Crimped-Staple.pdf
    kind: datasheet
    license: manufacturer datasheet, linked not reproduced
  dyneema-portfolio:
    title: Dyneema product portfolio, fibre grades and uses (Dyneema website)
    id: Dyneema product portfolio page
    url: https://www.dyneema.com/design-with-dyneema/dyneema-product-portfolio
    kind: web
    license: manufacturer web page, linked not reproduced
  wiki-uhmwpe:
    title: Ultra-high-molecular-weight polyethylene, Wikipedia
    id: Wikipedia article, properties, gel spinning and uses sections
    url: https://en.wikipedia.org/wiki/Ultra-high-molecular-weight_polyethylene
    kind: web
    license: CC BY-SA, linked not reproduced
  marlow-d12:
    title: Marlow Ropes D12+ 75/78 datasheet (single braid rope, Dyneema SK75 or SK78)
    id: D12+ 75/78, 2024 datasheet
    url: https://shop.marlowropes.com/content/files/datasheets/defence/datasheets%20with%20iso%2014001/d12+%207578%202024.pdf
    year: 2024
    kind: datasheet
    license: manufacturer datasheet, linked not reproduced
  mdpi-barrier-net:
    title: Study on the Aging Behavior of an Ultra-High Molecular Weight Polyethylene Fiber Barrier Net in a Marine Environment
    id: Materials 2022, 15(16), 5599, doi 10.3390/ma15165599
    url: https://www.ebi.ac.uk/europepmc/webservices/rest/PMC9413766/fullTextXML
    year: 2022
    kind: paper
    license: CC BY (MDPI, open access); read from full-text XML on Europe PMC
  nist-atomic-weights:
    title: NIST Atomic Weights and Isotopic Compositions for carbon and hydrogen
    id: NIST standard atomic weight intervals, C and H
    url: https://physics.nist.gov/cgi-bin/Compositions/stand_alone.pl?ele=C&all=all&ascii=html
    kind: database
    license: public domain (NIST)
  tivar-vmx-sds:
    title: Mitsubishi Chemical Advanced Materials, TIVAR VMX food-grade UHMW-PE safety data sheet (Boedeker copy, Feb 2024)
    id: UHMWPE sheet-grade SDS, rev. Feb 2024
    url: https://www.boedeker.com/Portals/0/Safety%20Data%20Sheets%20SDS/MCAM/MCAM-TIVAR-VMX-FOOD-GRADE-UHMW-EN-SDS-1609-211004-feb-2024.pdf
    year: 2024
    kind: datasheet
    license: safety data sheet, linked not reproduced
  wiki-ethylene:
    title: Ethylene, Wikipedia
    id: Ethylene article, production and industrial process sections
    url: https://en.wikipedia.org/wiki/Ethylene
    kind: web
    license: CC BY-SA, linked not reproduced
license: CC-BY-4.0
updated: '2026-11-01'
review:
  status: draft
  method: assistant
  checked_values: 16
  unreachable: 0
  caveats: 5
  note: 'Values were read by an AI assistant on 2026-11-01 from the pages named in each entry. The Dyneema staple values come from a MiniFIBERS datasheet PDF read with pdftotext. The SK75 density and yield strength come from a Wikipedia article (secondary source). Rope values come from a Marlow datasheet. The barrier-net breaking forces come from a 2022 paper read from its full text. Caveats: no Dyneema or Spectra safety data sheet was read, the hazard entries use a UHMWPE sheet-grade SDS; no fibre tensile datasheet for SK75 was found; the rope melting point (140 °C) and staple melting range (144 to 152 °C) differ and are both recorded; UV evidence is partly qualitative.'
story:
  recipe:
    line: Dyneema and Spectra are made from ultra-high-molecular-weight polyethylene, polymerised from ethylene with Kaminsky (metallocene) or Ziegler-Natta catalysts, and gel-spun from solution into oriented fibre, per the Wikipedia article. Wikipedia describes them as lightweight high-strength oriented-strand gels spun through a spinneret. Standard atomic weights for carbon and hydrogen are published by NIST.
    parts:
      - name: Ethylene
        symbol: C2H4
        role: The only monomer, polymerised to the repeat unit. The catalyst and processing set the chain length and the fibre form, not the chemistry.
      - name: Carbon
        symbol: C
        role: Two carbons per repeat unit, forming the -CH2-CH2- backbone.
      - name: Hydrogen
        symbol: H
        role: Four hydrogens per repeat unit, on the backbone carbons.
  risk_groups:
    - title: For people
      level: 0
      verdict: No GHS classification in the UHMWPE SDS
      lead: The sheet-grade UHMWPE SDS gives no GHS classification, but its dust can burn or explode. No Dyneema fibre SDS was read.
      points:
        - label: Classification
          line: The TIVAR VMX SDS prints GHS Classification None and Signal Word None, with no hazard statements.
        - label: Dust
          line: Finely divided dust can be flammable and form an explosive mixture with air, per the same SDS.
    - title: If it fails
      lead: The failure routes in the sources are heat, UV and creep under load.
      level: 2
      verdict: Heat and UV both weaken the fibre
      points:
        - label: Heat
          line: The staple datasheet gives a continuous use limit of 70 °C and says strength and modulus decrease at higher temperatures.
        - label: Rope
          line: The Marlow rope sheet gives a critical temperature of 80 °C, above which exposure results in permanent strength loss.
        - label: UV
          line: In the barrier-net study, UV ageing lowered breaking strength faster than salt spray, and the fibre showed cracks after UV irradiation.
    - title: Handling
      points:
        - label: Temperature
          line: Keep the fibre below the continuous use limit of 70 °C on the staple datasheet.
        - label: Sunlight
          line: Protect exposed lines from long sunlight exposure, since the barrier-net study found UV the most damaging of the ageing routes it tested.
  why: Dyneema and Spectra are high-modulus polyethylene (HMPE) fibres, a gel-spun form of ultra-high-molecular-weight polyethylene with a molar mass of 2 to 6 million daltons. The MiniFIBERS staple datasheet gives a specific gravity of 0.975 and a tenacity of about 3.0 GPa, so the fibre is light for the load it carries. Wikipedia gives a density as low as 0.97 g/cm3 for Dyneema SK75. The fibre is used where strength for weight matters, such as space tethers, mooring lines and lifting slings.
  uses:
    - where: Space tether
      line: The ESA and Russian Young Engineers' Satellite 2 flew a UHMWPE space tether in 2007, according to the Wikipedia article. The article does not name the grade.
    - where: Mooring and lifting
      line: Dyneema SK78 is listed by Dyneema for mooring lines, sailing lines and engineered lifting slings, with high fatigue, creep and abrasion resistance.
    - where: Single-braid rope
      line: Marlow builds an all-round single-braid rope from Dyneema SK75 or SK78, as a lighter alternative to steel wire.
  can_do:
    - label: Light for its strength
      value: 0.975 g/cm3
      benchmark: density
      line: The staple datasheet prints a specific gravity of 0.975. Wikipedia gives 0.97 g/cm3 for Dyneema SK75, and says ships' hawsers made from the fibre float on sea water.
    - label: High tensile strength
      value: about 3.0 GPa
      benchmark: ultimate_tensile_strength
      line: The staple datasheet prints a tenacity of about 3.0 GPa. Wikipedia gives gel-spun fibre yield strengths as high as 2.4 GPa, which measures a different quantity.
    - label: Stiffness
      value: 104 GPa
      benchmark: elastic_modulus
      line: The staple datasheet prints a modulus of about 104 GPa.
    - label: Load after salt spray
      value: 655 N
      benchmark: breaking_force
      line: A UHMWPE fibre barrier net kept a breaking force of 655 N after salt spray ageing in the 2022 study.
  compare: The staple, the rope and the barrier net in this profile differ in form, so their values are not ranked against each other. The staple datasheet gives a continuous use limit of 70 °C, while the rope sheet gives a critical temperature of 80 °C with permanent strength loss above it, so the rope value should not be read as the staple's. The staple tenacity of about 3.0 GPa and the gel-spun yield strength of 2.4 GPa measure different things. The UHMWPE sheet profile in this set is a moulded form and is not compared here.
  compare_rows:
    - label: Density
      benchmark: density
    - label: Tensile strength
      benchmark: ultimate_tensile_strength
    - label: Modulus
      benchmark: elastic_modulus
  handling:
    - Specify the form (staple, rope or barrier net), since the heat limits and breaking forces differ between them.
    - Keep the fibre below the 70 °C continuous use limit for the staple, and below the 80 °C rope critical temperature.
    - Check the current supplier data sheet for the grade in use, since no fibre SDS was read for this profile.
  good_for:
    - 'Light load-bearing lines: a specific gravity of 0.975 for the staple, and 0.97 g/cm3 for Dyneema SK75.'
    - 'High tensile load per weight: a tenacity of about 3.0 GPa for the staple.'
    - 'Chemical exposure: excellent chemical resistance is stated on the staple datasheet and the rope sheet.'
  watch_out:
    - 'Heat: the continuous use limit is 70 °C for the staple, and the rope sheet gives a critical temperature of 80 °C.'
    - 'UV: the 2022 barrier-net study found that UV ageing lowers breaking strength faster than salt spray, although the datasheets rate UV resistance highly.'
    - 'Creep under load: creep depends on load, temperature and time, per the rope sheet.'
    - 'Melting: the staple melts at 144 to 152 °C and the rope sheet gives 140 °C, so the value depends on the form read.'
  verdict: Dyneema and Spectra HMPE fibre is a light, high-strength polyethylene fibre, with a specific gravity of 0.975 and a tenacity of about 3.0 GPa for the staple datasheet read. Its limits are heat, with a 70 °C continuous use limit, and UV ageing, which the barrier-net study found to be faster than salt spray. No space-flight, outgassing or atomic oxygen data were found for this fibre.