Polypropylene PP

spore: profile
id: polypropylene
spore_version: 0.2
family: polyolefins
name: Polypropylene
abbreviation: PP
role: thermoplastic for moulding, films and battery separators
category: polymers
type: polyolefins
summary: |
  Polypropylene (PP) is a semicrystalline polyolefin, sold as a homopolymer or as a random copolymer with a second monomer. Two LyondellBasell grades read for this profile have a density of 0.90 g/cm3 and melt flow rates of 12 g/10 min (Moplen HP500N, homopolymer) and 25 g/10 min (Moplen RP348R, random copolymer) at 230 °C/2.16 kg. As a sample on the MISSE 2 experiment in low Earth orbit it had an atomic oxygen erosion yield of 2.68e-24 cm3/atom, close to the 3.36e-24 cm3/atom predicted by NASA. A 14 µm Celgard monolayer PP membrane is sold as a lithium battery separator with 43 % porosity and zero transverse shrinkage at 105 °C.
best_for: 'Light battery separators and moulded parts: a 14 µm Celgard PP1410 monolayer at 43 % porosity and 290 gf puncture strength (typical), and a 0.90 g/cm3 density in the LyondellBasell grades'
weakest_at: 'Heat and atomic oxygen: heat deflection temperatures of 80 °C to 97 °C in the grades read, and an erosion yield of 2.68e-24 cm3/atom in low Earth orbit'
identity:
  formula: (C3H6)n; repeat unit C3H6 as printed in the NASA TM polymer table
  cas: 9003-07-0
  source: netzsch-pp-sds
  where: Section 1.1 (product name Polypropylene, CAS-No. 9003-07-0) and Section 3.1; Anchor Packaging SDS Section 3 also prints CAS 9003-07-0 for Polypropylene at 100 % by weight
tags:
  environments:
    - low-earth-orbit
  stresses:
    - atomic-oxygen
    - vacuum-and-outgassing
  applications:
    - batteries
    - electronics-and-chips
properties:
  - benchmark: melt_flow_rate
    label: Melt flow rate, Moplen HP500N (homopolymer)
    value: 12
    unit: g/10 min
    scope: material
    conditions:
      temperature: 230 °C
      load: 2.16 kg
      grade: Moplen HP500N, homopolymer
    method: Typical value printed on the manufacturer product page
    status: ground
    source: lyb-hp500n
    where: Typical properties table, Melt Flow Rate row
  - benchmark: density
    label: Density, Moplen HP500N (homopolymer)
    value: 0.9
    unit: g/cm3
    scope: material
    conditions:
      grade: Moplen HP500N, homopolymer
      temperature: not printed on the page
    method: Typical value printed on the manufacturer product page; no test standard printed
    status: ground
    source: lyb-hp500n
    where: Typical properties table, Density row
  - benchmark: flexural_modulus
    label: Flexural modulus, Moplen HP500N
    value: 1480
    unit: MPa
    scope: material
    conditions:
      grade: Moplen HP500N
      test: not printed on the page
    method: Typical value printed on the manufacturer product page; no test standard printed
    status: ground
    source: lyb-hp500n
    where: Typical properties table, Flexural Modulus row
  - benchmark: tensile_yield_strength
    label: Tensile strength at yield, Moplen HP500N
    value: 34
    unit: MPa
    scope: material
    conditions:
      grade: Moplen HP500N
      test: not printed on the page
    method: Typical value printed on the manufacturer product page; no test standard printed
    status: ground
    source: lyb-hp500n
    where: Typical properties table, Tensile Strength at Yield row
  - benchmark: izod_impact
    label: Notched Izod impact strength, Moplen HP500N
    value: 25
    unit: J/m
    scope: material
    conditions:
      grade: Moplen HP500N
      temperature: 23 °C
    method: Typical value printed on the manufacturer product page
    status: ground
    source: lyb-hp500n
    where: Typical properties table, Notched Izod Impact Strength row
  - benchmark: heat_deflection_temperature
    label: Deflection temperature under load, Moplen HP500N
    value: 97
    unit: °C
    scope: material
    conditions:
      grade: Moplen HP500N
      load: 0.46 N/mm2
    method: Typical value printed on the manufacturer product page
    status: ground
    source: lyb-hp500n
    where: Typical properties table, Deflection Temperature Under Load row
  - benchmark: melt_flow_rate
    label: Melt flow rate, Moplen RP348R (random copolymer)
    value: 25
    unit: g/10 min
    scope: material
    conditions:
      temperature: 230 °C
      load: 2.16 kg
      grade: Moplen RP348R, random copolymer
    method: Typical value printed on the manufacturer product page
    status: ground
    source: lyb-rp348r
    where: Typical properties table, Melt Flow Rate row
  - benchmark: density
    label: Density, Moplen RP348R (random copolymer)
    value: 0.9
    unit: g/cm3
    scope: material
    conditions:
      temperature: 23 °C
      grade: Moplen RP348R, random copolymer
    method: Typical value printed on the manufacturer product page
    status: ground
    source: lyb-rp348r
    where: Typical properties table, Density (23 °C) row
  - benchmark: tensile_modulus
    label: Tensile modulus, Moplen RP348R
    value: 1150
    unit: MPa
    scope: material
    conditions:
      grade: Moplen RP348R
      test: not printed on the page
    method: Typical value printed on the manufacturer product page; no test standard printed
    status: ground
    source: lyb-rp348r
    where: Typical properties table, Tensile Modulus row
  - benchmark: tensile_yield_strength
    label: Tensile stress at yield, Moplen RP348R
    value: 30
    unit: MPa
    scope: material
    conditions:
      grade: Moplen RP348R
      test: not printed on the page
    method: Typical value printed on the manufacturer product page; no test standard printed
    status: ground
    source: lyb-rp348r
    where: Typical properties table, Tensile Stress at Yield row
  - benchmark: vicat_softening_temperature
    label: Vicat softening temperature (A50), Moplen RP348R
    value: 130
    unit: °C
    scope: material
    conditions:
      grade: Moplen RP348R
      method_as_printed: Vicat A50
    method: Typical value printed on the manufacturer product page
    status: ground
    source: lyb-rp348r
    where: Typical properties table, Vicat Softening Temperature (A50) row
  - benchmark: heat_deflection_temperature
    label: Heat deflection temperature B (0.45 MPa, unannealed), Moplen RP348R
    value: 80
    unit: °C
    scope: material
    conditions:
      grade: Moplen RP348R
      load: 0.45 MPa
      annealing: unannealed
    method: Typical value printed on the manufacturer product page
    status: ground
    source: lyb-rp348r
    where: Typical properties table, Heat Deflection Temperature B row
  - benchmark: flexural_modulus
    label: Flexural modulus, Moplen RP348N (random copolymer)
    value: 1050
    unit: MPa
    scope: material
    conditions:
      grade: Moplen RP348N, random copolymer
      test: not printed on the page
    method: Typical value printed on the manufacturer product page; no test standard printed
    status: ground
    source: lyb-rp348n
    where: Typical properties table, Flexural Modulus row
  - benchmark: izod_impact
    label: Notched Izod impact strength, Moplen RP348N (random copolymer)
    value: 70
    unit: J/m
    scope: material
    conditions:
      grade: Moplen RP348N, random copolymer
      temperature: 23 °C
    method: Typical value printed on the manufacturer product page
    status: ground
    source: lyb-rp348n
    where: Typical properties table, Notched Izod Impact Strength row
  - benchmark: melting_point
    label: Melting point / melting range, polypropylene
    value: 140
    value_high: 170
    unit: °C
    scope: material
    conditions:
      form: solid plastic granules, white
      product: Polypropylene, CAS 9003-07-0
    method: Value printed in the product safety data sheet, physical and chemical properties block
    status: ground
    source: netzsch-pp-sds
    where: Section 9, Melting point / Melting range row (Appearance and Change in condition block)
  - benchmark: atomic_oxygen_erosion_yield
    label: Atomic oxygen erosion yield, polypropylene (MISSE 2)
    value: 2.68e-24
    unit: cm3/atom
    scope: material
    conditions:
      platform: ISS, MISSE 2 PEACE, low Earth orbit
      table: Table I, MISSE 2 PEACE polymers erosion yield data
    method: Measured on MISSE 2 flight samples and listed in NASA TM-2008-215490, Table I
    status: flight
    source: nasa-tm-2008-215490
    where: Table I (MISSE 2 PEACE polymers erosion yield data), row Polypropylene, PP
  - benchmark: atomic_oxygen_erosion_yield
    label: Atomic oxygen erosion yield, polypropylene (predicted)
    value: 3.36e-24
    unit: cm3/atom
    scope: material
    conditions:
      basis: predictive tool, NASA TM-2008-215490
    method: Predicted by the NASA predictive tool; listed in Table VII next to the MISSE 2 measured value
    status: prediction
    source: nasa-tm-2008-215490
    where: Table VII (comparison of predicted and actual measured atomic oxygen erosion yields), row Polypropylene, PP
  - benchmark: thickness
    label: Thickness, Celgard PP1410 monolayer
    value: 14
    unit: µm
    scope: material
    conditions:
      product: Celgard PP1410, 14 µm monolayer microporous membrane (PP)
    method: Typical value printed on the manufacturer datasheet
    status: ground
    source: celgard-pp1410
    where: Technical Data (Typical Properties) table, Basic Film Properties, Thickness row
  - benchmark: gurley
    label: Gurley (JIS), Celgard PP1410
    value: 185
    unit: s
    scope: material
    conditions:
      product: Celgard PP1410
      method_as_printed: Gurley (JIS)
    method: Typical value printed on the manufacturer datasheet
    status: ground
    source: celgard-pp1410
    where: Technical Data (Typical Properties) table, Gurley (JIS) row
  - benchmark: porosity
    label: Porosity (calculated), Celgard PP1410
    value: 43
    unit: '%'
    scope: material
    conditions:
      product: Celgard PP1410
      basis: calculated, as printed
    method: Typical value printed on the manufacturer datasheet, marked calculated
    status: ground
    source: celgard-pp1410
    where: Technical Data (Typical Properties) table, Porosity (calculated) row
  - benchmark: puncture_strength
    label: Puncture strength (typical), Celgard PP1410
    value: 290
    unit: gf
    scope: material
    conditions:
      product: Celgard PP1410
      minimum_as_printed: 200 gf
    method: Typical value printed on the manufacturer datasheet (minimum 200 gf printed alongside)
    status: ground
    source: celgard-pp1410
    where: Technical Data (Typical Properties) table, Puncture Strength row
  - benchmark: thermal_shrinkage
    label: TD shrinkage at 105 °C, 1 hour (typical), Celgard PP1410
    value: 0
    unit: '%'
    scope: material
    conditions:
      temperature: 105 °C
      time: 1 hour
      product: Celgard PP1410
    method: Typical value printed on the manufacturer datasheet
    status: ground
    source: celgard-pp1410
    where: Technical Data (Typical Properties) table, TD Shrinkage row
corrosion:
  - environment: UV exposure in the laboratory, 365 nm lamp
    headline: Light stabilisers protect PP outdoors, and a 2020 study tested two HALS and one nano-ZnO UV absorber in PP films.
    effect: The study exposed films with 0.5 to 1.25 wt % additive in 40 phr PP for up to 6 weeks at 16.9 mW/cm2, a dose the authors put at 121 times Texas sunlight. The 0-week elongation at break is 279 to 299 mm. The tables read give no retention figure after exposure.
    conditions:
      basis: PP films, laboratory UV lamp; not a service test
      reference: Brostow et al. 2020, Table 1 and Section 2.4
    source: brostow-2020-uv
    where: Section 2.4 and Table 4, Section 3.2
  - environment: Temperatures above 100 C in service
    headline: PP is liable to chain degradation above 100 C, and oxidation attacks the tertiary carbon.
    effect: Wikipedia states that PP is liable to chain degradation from exposure to temperatures above 100 °C, and that oxidation usually occurs at the tertiary carbon centres, breaking the chain by reaction with oxygen.
    conditions:
      basis: general statement, no test condition given in the source
    source: wikipedia-polypropylene
    where: Chemical and physical properties, Degradation
  - environment: Long-term service with UV and oxygen exposure
    headline: Antioxidants and UV-absorbing additives are the stated protection for PP.
    effect: Wikipedia states that PP may be protected by various polymer stabilisers, including UV-absorbing additives and anti-oxidants. Brostow et al. 2020 state that HALS act by inhibiting degradation after free radicals form, rather than by absorbing UV radiation.
    conditions:
      basis: general statement; the HALS mechanism is a statement in the paper
    source: brostow-2020-uv
    where: Section 1
  - environment: Below 0 C
    headline: PP becomes brittle below 0 C.
    effect: Wikipedia states that below 0 °C, PP becomes brittle. The page gives no glass transition value.
    conditions:
      basis: general statement, no test condition given in the source
    source: wikipedia-polypropylene
    where: Chemical and physical properties, Thermal properties
risks:
  hazards:
    - text: Classification according to Regulation (EC) No 1272/2008 is printed as None, and the labelling is printed as None. PBT and vPvB are printed as not applicable.
      ghs: []
      source: netzsch-pp-sds
      where: Sections 2.1 and 2.2
    - text: Anchor Packaging states the product is an article and is exempt from GHS labelling and SDS classification. Signal word, pictograms and hazard phrases are printed as Not Applicable.
      ghs: []
      source: anchor-pp-sds
      where: Opening statement and Section 2
  failure_risks:
    - mode: Atomic oxygen erosion in low Earth orbit
      trigger: Exposure of a polypropylene part to atomic oxygen in low Earth orbit, as on the MISSE 2 flight
      consequence: Surface erosion at a yield of 2.68e-24 cm3/atom as measured on MISSE 2, and 3.36e-24 cm3/atom predicted by NASA.
      severity: moderate
      source: nasa-tm-2008-215490
      where: Table I and Table VII
  side_effects: []
  handling:
    - text: The product is a solid plastic granule; the SDS prints no classification and no special hazard for handling.
      source: netzsch-pp-sds
  mitigations: []
uses:
  - application: batteries
    device: Microporous separator membrane in lithium battery cells
    example: Celgard PP1410, a 14 µm monolayer microporous PP membrane for high power lithium battery systems. The datasheet lists zero TD shrinkage as a benefit for reduced internal shorting.
    source: celgard-pp1410
    where: Product Name and Description; Primary Applications; Product Benefits
  - application: electronics-and-chips
    device: Polymer sample on a space flight experiment
    example: Polypropylene on the MISSE 2 PEACE tray, flown on the ISS in low Earth orbit, with erosion yield listed in NASA TM-2008-215490.
    source: nasa-tm-2008-215490
    where: Table I
supply:
  - subject: Propylene (monomer for PP)
    demand: In the year 2013 about 85 million tonnes of propylene were processed worldwide (Wikipedia, Uses section).
    routes: Steam cracking is the dominant technology. Propane feedstock gives about 15 % propylene, refinery-grade propene from separation about 50 to 70 %, and high-severity FCC about 20 to 25 % by mass. Propane dehydrogenation (CATOFIN, OLEFLEX) is a minority of the market.
    producers: []
    critical_lists: []
    substitutes: []
    source: wikipedia-propylene
    where: Market; Uses; Steam cracking; Fluid catalytic cracking; Other commercialized methods
  - subject: Polypropylene (global output)
    demand: Approximately 86.74 million tons of polypropylene were produced globally in 2022, against a capacity of about 97.86 million tons. The article cites no primary source.
    routes: Polymerised from propylene with TiCl4 on MgCl2 heterogeneous catalysts, or with metallocene catalysts for syndiotactic PP (see recipe).
    producers: []
    critical_lists: []
    substitutes: []
    source: plasticpractical-pp-2022
    where: Key Takeaways and FAQ; producers named in the text with no tonnages
    abundance: 'Producers named in the source (no country shares given): Braskem; Reliance Industries; ExxonMobil; Borouge.'
  - subject: Polypropylene (rank among plastics)
    demand: Polypropylene is the second-most widely produced commodity plastic, after polyethylene.
    routes: []
    producers: []
    critical_lists: []
    substitutes: []
    source: wikipedia-polypropylene
    where: Lead
documents:
  - title: LyondellBasell product page, Moplen HP500N (homopolymer)
    type: datasheet
    url: https://www.lyondellbasell.com/en/polymers/p/Moplen-HP500N/e8c2d3bb-d271-459f-a439-629a5d85a7da
  - title: LyondellBasell product page, Moplen RP348R (random copolymer)
    type: datasheet
    url: https://www.lyondellbasell.com/en/polymers/p/Moplen-RP348R/aecfd785-14f8-4ea8-8b75-8672e262abe4
  - title: LyondellBasell product page, Moplen RP348N (random copolymer)
    type: datasheet
    url: https://lyondellbasell.com/en/polymers/p/Moplen-RP348N/b92d9cbe-872c-438a-bbe8-18632615e9f0
  - title: Banks, de Groh and Backus, Atomic Oxygen Erosion Yield Predictive Tool for Spacecraft Polymers in Low Earth Orbit, NASA/TM-2008-215490
    type: report
    url: https://ntrs.nasa.gov/citations/20090011780
    year: 2008
  - title: Celgard PP1410 Monolayer Microporous Membrane datasheet
    type: datasheet
    url: https://www.celgard.com/storage/components/pp1410_com_data_2022-04_20079.pdf
    year: 2022
  - title: NETZSCH product safety data sheet, Polypropylene, version 1.1
    type: sds
    url: https://analyzing-testing.netzsch.com/_Resources/Persistent/f/0/3/3/f0331bad3b5d235718c8474ba9e2a5ef382773a3/PSDS%20E%20Polypropylene%201.1%20%281%29.pdf
    year: 2023
  - title: Anchor Packaging SDS, Rigid Polypropylene (2019)
    type: sds
    url: https://anchorpackaging.com/wp-content/uploads/2021/07/AnchorPackaging-SDS-Rigid-Polypropylene-2019.pdf
    year: 2019
  - title: NIST Atomic Weights and Isotopic Compositions, carbon and hydrogen
    type: database
    url: https://physics.nist.gov/cgi-bin/Compositions/stand_alone.pl?ele=C&all=all&ascii=html
  - title: Brostow, Lu, Gencel and Osmanson, Effects of UV Stabilizers on Polypropylene Outdoors, Materials (Basel) 13(7), 1626
    type: paper
    url: https://pmc.ncbi.nlm.nih.gov/articles/PMC7178429/
    year: 2020
gaps:
  - 'Polypropylene copolymer density and melting point from a manufacturer datasheet: the RP348N page prints no density, and no melting point was printed on the RP348R page.'
  - 'Celgard PP1410 is a monolayer separator and a datasheet for a PP product of the 2500 family or a 25 µm grade was not read: the Celgard 3419S/3420 datasheet PDF could not be read.'
  - 'Electronics use (dielectric, circuit, packaging film): no sourced property value was read in this run.'
  - Chemical resistance of PP (solvents, acids, bases) was not read on a fetched page in this run.
  - Producer tonnages for PP and propylene were not found on a primary source. The producer names come from a market page with no figures, and the 2022 global total is uncited.
  - 'UV ageing: no retention of tensile strength or elongation after UV exposure was read; the Brostow et al. 2020 tables give 0-week values only.'
  - 'Supply and producers: no USGS or market source was read for polypropylene.'
  - Hazard text of the Nayara Energy homopolymer sheet (Flammable Solid Category 1) was not opened, so it is not recorded; the IRPC SDS (403) and Sigma-Aldrich pages could not be read.
  - No test standard (ISO or ASTM number) is printed on the LyondellBasell typical-property tables, so conditions for density, modulus, yield and HDT are as far as the pages state.
  - No outgassing, total mass loss or UV, radiation or thermal-cycling data for polypropylene in space was read in this run.
  - Bulk density of 400 to 620 g/cm3 printed in the NETZSCH SDS is a powder property and is not recorded as a material density.
sources:
  nist-atomic-weights:
    title: NIST Atomic Weights and Isotopic Compositions for All Elements (C and H rows)
    id: 'NIST standard atomic weight table: C [12.0096, 12.0116]; H [1.007 84, 1.008 11]'
    url: https://physics.nist.gov/cgi-bin/Compositions/stand_alone.pl?ele=C&all=all&ascii=html
    kind: database
    license: US government data
  wikipedia-polypropylene:
    title: Polypropylene, Wikipedia
    id: Polypropylene article, Chemical and physical properties
    url: https://en.wikipedia.org/wiki/Polypropylene
    kind: web
    license: CC BY-SA 4.0, linked not reproduced
  wikipedia-propylene:
    title: Propylene, Wikipedia
    id: Propylene article, Market and production sections
    url: https://en.wikipedia.org/wiki/Propylene
    kind: web
    license: CC BY-SA 4.0, linked not reproduced
  brostow-2020-uv:
    title: Effects of UV Stabilizers on Polypropylene Outdoors
    id: Brostow, Lu, Gencel and Osmanson, Materials (Basel) 13(7), 1626
    url: https://pmc.ncbi.nlm.nih.gov/articles/PMC7178429/
    year: 2020
    kind: paper
    license: open access article, linked not reproduced
  plasticpractical-pp-2022:
    title: 'Global Production: How Much Polypropylene Is Produced Each Year?'
    id: Plastic Practical article, FAQ and Key Takeaways (no primary source cited)
    url: https://plasticpractical.com/global-production-how-much-polypropylene-is-produced-each-year/
    kind: web
    license: web article, linked not reproduced
  lyb-hp500n:
    title: Moplen HP500N, LyondellBasell product page (typical properties)
    id: Product page, typical properties table
    url: https://www.lyondellbasell.com/en/polymers/p/Moplen-HP500N/e8c2d3bb-d271-459f-a439-629a5d85a7da
    year: 2026
    kind: datasheet
    license: manufacturer web page, linked not reproduced
  lyb-rp348r:
    title: Moplen RP348R, LyondellBasell product page (typical properties)
    id: Product page, typical properties table
    url: https://www.lyondellbasell.com/en/polymers/p/Moplen-RP348R/aecfd785-14f8-4ea8-8b75-8672e262abe4
    year: 2026
    kind: datasheet
    license: manufacturer web page, linked not reproduced
  lyb-rp348n:
    title: Moplen RP348N, LyondellBasell product page (typical properties)
    id: Product page, typical properties table
    url: https://lyondellbasell.com/en/polymers/p/Moplen-RP348N/b92d9cbe-872c-438a-bbe8-18632615e9f0
    year: 2026
    kind: datasheet
    license: manufacturer web page, linked not reproduced
  nasa-tm-2008-215490:
    title: Atomic Oxygen Erosion Yield Predictive Tool for Spacecraft Polymers in Low Earth Orbit
    id: NASA/TM-2008-215490 (Banks, de Groh and Backus, 2008), NTRS 20090011780
    url: https://ntrs.nasa.gov/citations/20090011780
    year: 2008
    kind: report
    license: NASA public document
  celgard-pp1410:
    title: Celgard PP1410 Monolayer Microporous Membrane (PP), typical properties
    id: Celgard PP1410 data sheet, 2022-04
    url: https://www.celgard.com/storage/components/pp1410_com_data_2022-04_20079.pdf
    year: 2022
    kind: datasheet
    license: manufacturer datasheet, linked not reproduced
  netzsch-pp-sds:
    title: NETZSCH Product Safety Data Sheet, Polypropylene, version 1.1
    id: CAS 9003-07-0, revision 28.02.2023
    url: https://analyzing-testing.netzsch.com/_Resources/Persistent/f/0/3/3/f0331bad3b5d235718c8474ba9e2a5ef382773a3/PSDS%20E%20Polypropylene%201.1%20%281%29.pdf
    year: 2023
    kind: datasheet
    license: supplier SDS, linked not reproduced
  anchor-pp-sds:
    title: Anchor Packaging Safety Data Sheet, Rigid Polypropylene
    id: SDS, 2019 (file dated 2021-07 on server)
    url: https://anchorpackaging.com/wp-content/uploads/2021/07/AnchorPackaging-SDS-Rigid-Polypropylene-2019.pdf
    year: 2019
    kind: datasheet
    license: supplier SDS, linked not reproduced
license: CC-BY-4.0
updated: '2026-10-18'
review:
  status: draft
  method: assistant
  checked_values: 22
  unreachable: 6
  caveats: 6
  note: 'Values were read by an AI assistant on 2026-10-18 from the pages named in each entry. NASA Table I and Table VII were read from the text of the NTRS PDF. Unreachable: Celgard 3419S and 2500 datasheets, IRPC SDS (403), Braskem 6D83GA (404), PubChem polypropylene record (captcha), Anchor SDS fields beyond Section 2 and 3 were read from its text. Caveats: LyondellBasell values are typical with no test standard printed; HP500N and RP348R density are given without a test standard; the separator values are one manufacturer''s typical values for a 14 um product; the erosion yield is a flight value for one sample with its exposure time not read; the melting range is a SDS value and not a datasheet value.'
story:
  recipe:
    line: Polypropylene is made by chain-growth polymerisation of the monomer propylene (CH2=CH-CH3). The repeat unit is -[CH2-CH(CH3)]-, a head-to-tail chain with a methyl group on alternating carbons. Heterogeneous catalysts are prepared from TiCl4 with an MgCl2 support, and syndiotactic PP is made with metallocene catalysts.
    parts:
      - name: Carbon
        symbol: C
        atoms: 3
        role: 'Three carbons per repeat unit: two in the chain and one in the methyl group.'
        share_note: atomic_weight [12.0096, 12.0116]
      - name: Hydrogen
        symbol: H
        atoms: 6
        role: Six hydrogens per repeat unit, filling the chain and methyl sites.
        share_note: atomic_weight [1.007 84, 1.008 11]
  risk_groups:
    - title: For people
      lead: The SDS pages read here classify polypropylene as not hazardous under EU rules.
      level: 1
      verdict: Not classified in two SDSs
      points:
        - label: Classification
          line: The NETZSCH SDS prints the EU CLP classification and labelling as None, and the Anchor SDS treats the product as an article exempt from GHS labelling.
        - label: Handling
          line: The product is a solid granule with a melting range of 140 to 170 °C, as printed in the NETZSCH SDS.
    - title: If it fails
      lead: The failure route in these sources is erosion in orbit, measured on one flight sample.
      points:
        - label: Atomic oxygen
          line: On MISSE 2 the erosion yield was 2.68e-24 cm3/atom, against 3.36e-24 cm3/atom predicted. Both values come from the same NASA report.
  why: Polypropylene is a light, semicrystalline plastic. The LyondellBasell homopolymer Moplen HP500N has a density of 0.90 g/cm3 and a melt flow rate of 12 g/10 min at 230 °C/2.16 kg. The random copolymer Moplen RP348R has a melt flow rate of 25 g/10 min and a density of 0.90 g/cm3 at 23 °C. Its use as a battery separator is shown by the Celgard PP1410 monolayer, a 14 µm membrane with 43 % porosity.
  can_do:
    - label: Light and stiff enough
      value: 1480 MPa flexural modulus
      line: The homopolymer HP500N has a flexural modulus of 1480 MPa and a tensile strength at yield of 34 MPa, as printed on the product page. The copolymer RP348N has a flexural modulus of 1050 MPa.
    - label: Hold a separator shape
      value: 0 % TD shrinkage at 105 °C
      benchmark: thermal_shrinkage
      line: The Celgard PP1410 datasheet prints 0 % transverse-direction shrinkage at 105 °C for 1 hour, and a puncture strength of 290 gf typical (200 gf minimum).
    - label: Survive in orbit
      value: 2.68e-24 cm3/atom
      benchmark: atomic_oxygen_erosion_yield
      line: NASA lists a MISSE 2 erosion yield for polypropylene of 2.68e-24 cm3/atom, and predicts 3.36e-24 cm3/atom in its Table VII.
  compare: The sheet and datasheet values here are for different products, so read the table rows as examples, not a ranking. In this polymers in this site's profile set use different grades and test conditions, so they cannot be ranked from these values.
  compare_rows:
    - scope: material
      label: Density
      benchmark: density
    - scope: material
      label: Erosion yield
      benchmark: atomic_oxygen_erosion_yield
    - scope: material
      label: Thickness
      benchmark: thickness
  handling:
    - Specify the grade, since the homopolymer and copolymer differ in modulus and heat deflection.
    - Check the current supplier SDS for each grade before handling, since classification differs between the SDSs read.
    - Treat the Celgard and LyondellBasell values as typical, not as specification limits, as the sources state.
  good_for:
    - 'Battery separators: a 14 µm monolayer at 43 % porosity and 0 % TD shrinkage at 105 °C (Celgard PP1410).'
    - 'Light moulded parts: 0.90 g/cm3 density in both LyondellBasell grades read.'
    - 'Known atomic oxygen behaviour: 2.68e-24 cm3/atom on MISSE 2, measured in low Earth orbit.'
  watch_out:
    - 'Heat: the heat deflection temperature is 80 °C for RP348R and 97 °C for HP500N, so PP softens well below its melting range of 140 to 170 °C under load.'
    - Atomic oxygen erodes PP at 2.68e-24 cm3/atom, so exterior use needs protection or a rate allowance.
    - No outgassing, radiation or UV test for PP in space was found, so only the erosion yield is recorded.
    - Copolymer density and melting point from a datasheet were not found, and the SDS melting range is not a datasheet value.
  verdict: Polypropylene is a light plastic with a density of 0.90 g/cm3 in the grades read, a 14 µm separator with 43 % porosity and 0 % TD shrinkage at 105 °C, and a MISSE 2 erosion yield of 2.68e-24 cm3/atom in low Earth orbit. Its heat deflection of 80 to 97 °C limits use under load, and this profile has no sourced electronics or outgassing values.