Poly(methyl methacrylate) PMMA
(C5H8O2)n · CAS 9011-14-7
PMMA, also called acrylic or Plexiglas, is a clear, rigid thermoplastic.
Evidence level
5 of 5
Flown or field-proven
- 0Predicted only. No one has made it, or no measurement exists.
- 1Calculated. Only calculated or predicted values from sources.
- 2Lab-measured. Measured properties with their conditions stated.
- 3Space-relevant tests. Measured in conditions relevant to space, such as vacuum or atomic oxygen.
- 4Ground-qualified. Qualified for an application on the ground.
- 5Flown or field-proven. Flight or field results exist.
Strength and stiffness
80 MPa
Clarity
About 92% transmittance
Heat
Softens at 115 °C
In orbit
Erosion yield above 5.60e-24
Outgassing
0.51 to 0.81% mass loss
Recipe, share of the weight
- MMA atoms C5H8O2Methyl methacrylate
- C not statedCarbon
- H not statedHydrogen
- O not statedOxygen
Best for
A clear, rigid, easily shaped plastic for windows, lenses and covers (about 92% transmittance, refractive index 1.491) with low outgassing in the NASA database entries (0.51 to 0.81% mass loss)
Weakest at
Atomic oxygen in low Earth orbit (eroded faster than Kapton H), ultraviolet light in grades without a UV absorber, and heat (maximum permanent service temperature about 80 degC)
Risk at a glance
- People Low. Not classified as hazardous; the sheet burns
- If it fails High. Erosion by atomic oxygen in low Earth orbit
- Corrosion Severe. Atomic oxygen eroded PMMA faster than Kapton H polyimide on the ISS.
Quick facts: PMMA
| Property | Value | Basis |
|---|---|---|
| Density | 1.19 g/cm³ | 1 sourced value |
| Tensile strength | 80 MPa | 1 sourced value |
| Thermal conductivity | 0.19 W/(m·K) | 1 sourced value |
| Thermal expansion (CTE) | 70 ppm/K | 1 sourced value |
| Maximum service temperature | 80 °C | 1 sourced value |
What is the density of Poly (PMMA)?
Poly (PMMA) has a density of 1.19 g/cm³. The source and test conditions are listed in the properties table on this page.
What is the thermal conductivity of Poly (PMMA)?
Poly (PMMA) has a thermal conductivity of 0.19 W/(m·K). The source and test conditions are listed in the properties table on this page.
What is the coefficient of thermal expansion of Poly (PMMA)?
Poly (PMMA) has a coefficient of thermal expansion of 70 ppm/K. The source and test conditions are listed in the properties table on this page.
What is the tensile strength of Poly (PMMA)?
Poly (PMMA) has a tensile strength of 80 MPa. The source and test conditions are listed in the properties table on this page.
What is the maximum service temperature of Poly (PMMA)?
Poly (PMMA) has a maximum service temperature of 80 °C. The source and test conditions are listed in the properties table on this page.
What is Poly (PMMA) used for?
Uses recorded in the sources include Lens and window material listed in the NASA outgassing database; Aircraft glazing grades (ground and aviation use, not spacecraft); Flight sample on the ISS exterior (MISSE 2 PEACE experiment).
Why it exists
Poly(methyl methacrylate), or PMMA, is a thermoplastic, a polymer that softens when heated and can be melted and reshaped. It is made by linking many small methyl methacrylate molecules into long chains, and each repeat unit has the formula C5H8O2. It is sold as acrylic and under trade names such as Plexiglas and Acrylite. The chains do not pack into crystals, so the plastic is clear: the cast sheet grade lets through about 92% of visible light and has a refractive index of 1.491, close to that of glass. It is also rigid, with a modulus of 3300 MPa, and light, with a density of 1.19 g/cm³. Its weakness is that it softens early (Vicat softening at 115 °C) and that its chains are easily broken by ultraviolet light, radiation and atomic oxygen. That makes it a good clear window or lens material on the ground, and a material that needs checking before use on the outside of a spacecraft.
Where it's used
Lens and window materials in the NASA outgassing database
The NASA outgassing database lists PLEXIGLAS 11 UVA and PLEXIGLAS VS-100 OPTICAL with the usage lens, and acrylic safety glazing with the usage glazing. The database does not say which spacecraft used them.
Flown on the ISS as a test film
PMMA was one of 41 polymer samples flown on the outside of the ISS from 16 August 2001 to 30 July 2005 in the MISSE 2 PEACE experiment, to measure how fast atomic oxygen erodes each polymer.
Aircraft glazing on the ground
The manufacturer lists three cast grades (PLEXIGLAS GS 241, 245 and 249) as approved for aircraft glazing. This is aviation use, not spacecraft use.
Recipe
(C5H8O2)n
PMMA is made by polymerising the methyl methacrylate (MMA) monomer, C5H8O2, with radical initiation; anionic and living routes are also used, and emulsion, solution and bulk processes are routine (Wikipedia, Poly(methyl methacrylate), Production). Cast sheet, the highest-quality grade, is made by casting MMA mixed with initiators and possibly other additives into a form or mold, so polymerisation and moulding happen together. Extruded acrylic is made by melting solid acrylic pellets, and forcing them through dies (Wikipedia, Cast acrylic and Extruded acrylic). MMA itself is made mainly by the acetone cyanohydrin route (Wikipedia, Methyl methacrylate, Production).
| Ingredient | Share of the weight | What it does |
|---|---|---|
| Methyl methacrylate MMA | atoms C5H8O2 | Monomer; the repeat unit of PMMA has the same formula, C5H8O2 (PubChem CID 6658). |
| Carbon C | not stated | Element in the repeat unit. NIST standard atomic weight is printed as the interval [12.0096, 12.0116]. |
| Hydrogen H | not stated | Element in the repeat unit. NIST standard atomic weight is printed as the interval [1.00784, 1.00811]. |
| Oxygen O | not stated | Element in the repeat unit. NIST standard atomic weight is printed as the interval [15.99903, 15.99977]. |
Weight shares are as printed in the sources.
What it can do
Strength and stiffness
80 MPa
The cast PLEXIGLAS GS sheet has a tensile strength of 80 MPa at 23 °C (ISO 527-2) and a modulus of elasticity of 3300 MPa. Elongation at break is only 5.5%, so it is rigid and fairly brittle. Strength drops to 40 MPa at 70 °C.
Clarity
About 92% transmittance
The manufacturer lists a light transmittance of about 92% and a refractive index of 1.491 for the cast grade. The grade is UV-absorbing, so it blocks ultraviolet light.
Heat
Softens at 115 °C
The Vicat softening temperature is 115 °C and the maximum permanent service temperature is 80 °C. Thermal conductivity is 0.19 W/(m K), so it insulates, and thermal expansion is 7 × 10⁻⁵ per kelvin between 0 and 50 °C, much larger than metals or glass.
In orbit
Erosion yield above 5.60e-24
On the MISSE 2 flight (3.95 years, fluence 8.43e21 atoms/cm²) PMMA lost material faster than Kapton H, 3.00 × 10⁻²⁴ cm³/atom. Because samples eroded through, 5.60 × 10⁻²⁴ cm³/atom is a lower bound.
Outgassing
0.51 to 0.81% mass loss
Outgassing is the release of trapped gases and volatile compounds in vacuum, which can then condense on optics and sensors. NASA database entries for acrylic sheet show total mass loss (TML) of 0.51 to 0.81% and collected volatile condensable material (CVCM) of 0 to 0.05%, inside the NASA screening limits of 1.0% and 0.10% for a 125 °C, 24 hour vacuum test.
How it compares
In low Earth orbit, PMMA eroded faster than Kapton H polyimide (above 5.60 × 10⁻²⁴ against 3.00 × 10⁻²⁴ cm³/atom in the same MISSE 2 table), while fluoropolymers such as FEP (2.00 × 10⁻²⁵) and PTFE (1.42 × 10⁻²⁵) eroded far less. On mass loss in vacuum, one Plexiglas entry (VS-100 OPTICAL) is listed at 1% TML, right at the NASA screening limit, so grade matters. No source in this record compares PMMA with glass, metals or composites, so no such comparison is made.
The same measurements for each material, so you can compare them. Each row names the key condition under the value; the full conditions and methods are in the numbered notes under Technical details. Other materials are shown beside it; each was measured under its own conditions, so open its page before comparing closely. Compare every grade in the family.
| Measurement | PMMA | PAN |
|---|---|---|
| Thermal behavior and safety | ||
| Thermal conductivity, PLEXIGLAS GS | 0.19 W/(m K)7 | no data |
| Lifetime and stability | ||
| Total mass loss, PLEXIGLAS G acrylic sheet (NASA database entry GSC29989) | 0.81 % mass12 | no data |
| Collected volatile condensable material, PLEXIGLAS G acrylic sheet (NASA database entry GSC29989) | 0 % mass13 | no data |
| Physical and electrical | ||
| Density, PLEXIGLAS GS (cast sheet) | 1.19 g/cm³1 | 1.143 g/cm³ |
| Other measurements | ||
| Tensile strength at 23 degC, PLEXIGLAS GS | 80 MPa2 | no data |
| Modulus of elasticity (short-term), PLEXIGLAS GS | 3300 MPa3 | no data |
| Vicat softening temperature, PLEXIGLAS GS | 115 °C4 | no data |
| Maximum permanent service temperature, PLEXIGLAS GSValue listed by the manufacturer | 80 °C5 | no data |
| Coefficient of linear thermal expansion, PLEXIGLAS GS | 7×10^-5 1/K6 | no data |
| Light transmittance (tau D65), PLEXIGLAS GS | 92 %8 | no data |
| Refractive index nD20, PLEXIGLAS GS | 1.491 dimensionless9 | no data |
| Maximum water weight gain during immersion, PLEXIGLAS GS | 2.1 % mass10 | no data |
| Atomic oxygen erosion | > 5.6×10^-24 cm³/atom11 | no data |
| Total mass loss, PLEXIGLAS 11 UVA lens material (NASA database entry GSFC0460) | 0.57 % mass14 | no data |
| Total mass loss, ACRYLITE acrylic sheet (NASA database entry GSFC0915) | 0.51 % mass15 | no data |
| Total mass loss, acrylic safety glazing, polymethylmethacrylate (NASA database entry GSC28432) | 0.68 % mass16 | no data |
| Transmittance change at 360 nm after solar UV exposure, UV-transmitting acrylic (Reynolds sample 17) | -47.5 % change in transmittance17 | no data |
| Highest gamma dose in an optical and infrared study of PMMA foils | 500 kGy18 | no data |
Why choose it, and why not
Good for
- Clarity. The cast sheet transmits about 92% of visible light with a refractive index of 1.491.
- Low outgassing. NASA database entries for acrylic sheet show total mass loss of 0.51 to 0.81%.
- Light and rigid. Density is 1.19 g/cm³ and modulus 3300 MPa for the cast grade.
Watch out for
- Atomic oxygen. PMMA eroded faster than Kapton H on the ISS, and some samples eroded through.
- Ultraviolet light and radiation. A ground sunlight test cut transmittance at 360 nm by 47.5% in one sample, and gamma doses of 10 to 500 kGy added visible colour.
- Heat. Vicat softening is 115 °C and tensile strength falls from 80 MPa to 40 MPa between 23 °C and 70 °C.
- Thin evidence in space. No flight result for PMMA ultraviolet or radiation damage was found; those are ground tests.
PMMA is a clear, light, low-outgassing plastic that is a good window or lens material on the ground, but on the outside of a spacecraft in low Earth orbit it erodes under atomic oxygen faster than Kapton H, and ground tests show ultraviolet and gamma damage. It suits parts shielded from the orbital surface environment or protected by coatings, and no real mission use is documented in the sources read here.
Technical details
For scientists and researchers. Everything above comes from the record below: every number with its method, its conditions and its source.
Notes
The method, full conditions and any caveat for the numbered rows above.
| # | Measurement | Method | Conditions | Caveat |
|---|---|---|---|---|
| 1 | Density, PLEXIGLAS GS (cast sheet) | Typical value listed in the manufacturer's technical information | grade PLEXIGLAS GS 0F00; 0Z09 (cast)test standard ISO 1183temperature 23 °Chumidity 50% relative humidity | Extruded PLEXIGLAS XT also lists 1.19 g/cm3. NASA's MISSE 2 report uses 1.1628 g/cm3 for PMMA (Table II). A PMMA safety data sheet gives a relative density of 1.15 to 1.19. |
| 2 | Tensile strength at 23 degC, PLEXIGLAS GS | Typical value listed in the manufacturer's technical information | grade PLEXIGLAS GS 0F00; 0Z09 (cast)test standard ISO 527-2/1B/5temperature 23 °Chumidity 50% relative humidity | The same table gives 110 MPa at -40 degC and 40 MPa at 70 degC for GS. Extruded PLEXIGLAS XT gives 72 MPa at 23 degC. Elongation at break is 5.5% for GS (ISO 527-2/1B/5). |
| 3 | Modulus of elasticity (short-term), PLEXIGLAS GS | Typical value listed in the manufacturer's technical information | grade PLEXIGLAS GS 0F00; 0Z09 (cast)test standard ISO 527-2/1B/1temperature 23 °Chumidity 50% relative humidity | PLEXIGLAS XT also lists 3300 MPa. Flexural strength of GS is 115 MPa (ISO 178) and Poisson's ratio 0.37 (ISO 527-1). |
| 4 | Vicat softening temperature, PLEXIGLAS GS | Typical value listed in the manufacturer's technical information | grade PLEXIGLAS GS 0F00; 0Z09 (cast)test standard ISO 306, Method B 50 | A softening point, not a glass transition temperature. PLEXIGLAS XT lists 103 degC. Heat deflection temperature at 1.8 MPa is given as 105; 107 degC for the GS grades 0F00; 0Z09 (ISO 75). No glass transition temperature was read from an opened source. |
| 5 | Maximum permanent service temperature, PLEXIGLAS GS | — | grade PLEXIGLAS GS 0F00; 0Z09 (cast)basis permanent (long-term) use in air; no test standard given | PLEXIGLAS XT (extruded) is listed at 70 degC. Ground value in air, not a vacuum or orbit rating. |
| 6 | Coefficient of linear thermal expansion, PLEXIGLAS GS | Typical value listed in the manufacturer's technical information (written as 7 x 10-5, equal to 0.07 mm/m per degC) | grade PLEXIGLAS GS 0F00; 0Z09 (cast)test standard DIN 53752-Atemperature range 0 to 50 °C | — |
| 7 | Thermal conductivity, PLEXIGLAS GS | Typical value listed in the manufacturer's technical information | grade PLEXIGLAS GS 0F00; 0Z09 (cast)test standard DIN 52612 | Specific heat is listed as 1.47 J/(g K); the table gives no test standard for it. |
| 8 | Light transmittance (tau D65), PLEXIGLAS GS | Typical value listed in the manufacturer's technical information (printed as ~ 92) | grade PLEXIGLAS GS 0F00; 0Z09 (cast)test standard DIN 5036, Part 3light D65 illuminant, visible range | The table lists a reflection loss of 4% per surface in the visible range and total energy transmittance of 85% (DIN EN 410). The grade is marked UV-absorbing (the table lists no under UV transmission); the extruded XT 0A070 grade is UV transmitting. Sheet thickness for the transmittance value is not stated. |
| 9 | Refractive index nD20, PLEXIGLAS GS | Typical value listed in the manufacturer's technical information | grade PLEXIGLAS GS 0F00; 0Z09 (cast)test standard ISO 489temperature 20 °Cwavelength sodium D line (nD) | — |
| 10 | Maximum water weight gain during immersion, PLEXIGLAS GS | Typical value listed in the manufacturer's technical information | grade PLEXIGLAS GS 0F00; 0Z09 (cast)test standard ISO 62, Method 1state immersion in water, specimen 60 x 60 x 2 mm3 | Water absorption in 24 h at 23 degC from the dry state is 41 mg for the same specimen. Acrylic can release absorbed water in vacuum, which matters for outgassing. |
| 11 | Atomic oxygen erosion | Mass-loss erosion yield from the MISSE 2 flight samples (the report notes that for some stacked thin-film samples part or all of the area eroded through, so the listed yield is a lower bound, shown as greater than 5.60e-24) | experiment MISSE 2 PEACE polymers, exterior of the International Space Station (PEC 2 tray 1, Quest airlock)exposure 3.95 yr in low Earth orbit, 16 August 2001 to 30 July 2005comparison Kapton H polyimide measured 3.00e-24 cm3/atom in the same table | Density used for PMMA in the report is 1.1628 g/cm3 and ash fraction 2.80e-4 (Table II). The report's predictive tool gives 5.65e-24 cm3/atom for PMMA (Table VII). For comparison the same table has FEP at 2.00e-25 and PTFE at 1.42e-25 cm3/atom. |
| 12 | Total mass loss, PLEXIGLAS G acrylic sheet (NASA database entry GSC29989) | Value from the NASA Goddard outgassing database (data file as mirrored in the Wolfram Data Repository, NASA 'Outgassing Db' dated 19 November 2015) | material PLEXIGLAS G ACRYLIC SHEETdatabase id GSC29989manufacturer code ARKusage sheettest method NASA outgassing screening test: 125 °C for 24 h in vacuum, ASTM E 595 (stated for the database in RP-1124 Rev. 4) | Collected volatile condensable material is 0% and water vapour regained 0.29% for the same entry. The database file does not state the test conditions per entry; the 125 degC, 24 h conditions come from the NASA report describing the database. Other acrylic sheet entries are given in the following properties. |
| 13 | Collected volatile condensable material, PLEXIGLAS G acrylic sheet (NASA database entry GSC29989) | Value from the NASA Goddard outgassing database (data file as mirrored in the Wolfram Data Repository, NASA 'Outgassing Db' dated 19 November 2015) | material PLEXIGLAS G ACRYLIC SHEETdatabase id GSC29989manufacturer code ARKtest method NASA outgassing screening test: 125 °C for 24 h in vacuum, ASTM E 595 (stated for the database in RP-1124 Rev. 4) | The database lists 0 percent, which means below its reporting resolution, not necessarily exactly zero. The NASA screening limits quoted in RP-1124 are 1.0 percent TML and 0.10 percent CVCM. |
| 14 | Total mass loss, PLEXIGLAS 11 UVA lens material (NASA database entry GSFC0460) | Value from the NASA Goddard outgassing database (data file as mirrored in the Wolfram Data Repository) | material PLEXIGLAS 11 UVAdatabase id GSFC0460manufacturer code ROHusage lenstest method NASA outgassing screening test: 125 °C for 24 h in vacuum, ASTM E 595 (stated for the database in RP-1124 Rev. 4) | CVCM is 0%; water vapour regained is not available for this entry. A second PLEXIGLAS entry, VS-100 OPTICAL (GSFC0463), has TML 1% and CVCM 0.01%. |
| 15 | Total mass loss, ACRYLITE acrylic sheet (NASA database entry GSFC0915) | Value from the NASA Goddard outgassing database (data file as mirrored in the Wolfram Data Repository) | material ACRYLITE ACRYLIC SHEETdatabase id GSFC0915manufacturer code ACCusage structuraltest method NASA outgassing screening test: 125 °C for 24 h in vacuum, ASTM E 595 (stated for the database in RP-1124 Rev. 4) | CVCM is 0.05%; water vapour regained is not available for this entry. |
| 16 | Total mass loss, acrylic safety glazing, polymethylmethacrylate (NASA database entry GSC28432) | Value from the NASA Goddard outgassing database (data file as mirrored in the Wolfram Data Repository) | material ACRYLIC SAFETY GLAZING - POLYMETHOLMETHACRYLATE (spelling as in the database)database id GSC28432manufacturer code PTCusage glazingtest method NASA outgassing screening test: 125 °C for 24 h in vacuum, ASTM E 595 (stated for the database in RP-1124 Rev. 4) | CVCM is 0% and water vapour regained 0.27% for the same entry. |
| 17 | Transmittance change at 360 nm after solar UV exposure, UV-transmitting acrylic (Reynolds sample 17) | UV-Vis spectrophotometer transmittance before and after exposure (change from unexposed sample) | specimen Reynolds Polymer Technology UV-transmitting (UVT) cast acrylic, 9.5 mm path, polishedexposure outdoor sunlight in Madison, Wisconsin, 7 exposures of 3 to 4 hours, total 296 J/cm2 of UVwavelength 360 nmenvironment Earth air, not vacuum | A ground sunlight test on detector-grade acrylic without a UV absorber, not a space test. The same table gives +1.8% for Polycast sample 18 (263 J/cm2) and -3.2% for YenNan sample 19 (181 J/cm2); changes under 4% cannot be resolved. In 14 to 25 day exposures Polycast sample 7 lost 13.8% at 2192 J/cm2 (Table 3). Commercial acrylics normally contain UV absorbers, which the paper says boost stability. |
| 18 | Highest gamma dose in an optical and infrared study of PMMA foils | Optical absorption (transmission) and FTIR spectra before and after irradiation | source of radiation cobalt-60 gamma source, dose rate 2 kGy/hdoses 10, 50, 100 and 500 kGyspecimen CLAREX PMMA foils, 200 and 500 micrometres thick (Nitto Jushi Kogyo)temperature room temperaturemeasurement UV-Vis transmission 200 to 1100 nm and FTIR | A dose tested, not a tolerance limit. All doses created a new absorption band from 384 to 523 nm in the visible range (colour centres); it was strongest at 10 and 500 kGy and weaker at 50 and 100 kGy. The authors see cross-linking up to about 100 kGy and carbonyl group loss and chain scission dominating beyond it. |
Corrosion and compatibility
What happens when it meets other materials and environments.
| Environment | Concern | What happens |
|---|---|---|
| Atomic oxygen in low Earth orbit | severe | Atomic oxygen eroded PMMA faster than Kapton H polyimide on the ISS.1 |
| Ultraviolet light (ground sunlight test, in air) | moderate | Some acrylic without a UV absorber lost nearly half its transmittance at 360 nm after 296 J/cm2 of sunlight.2 |
| Gamma radiation (ground, cobalt-60) | moderate | Gamma doses from 10 to 500 kGy made PMMA foils absorb visible light.3 |
| Water, immersion | low | PMMA sheet takes up a little water, a maximum of 2.1% of its mass on immersion.4 |
| # | Environment | Details | Test conditions |
|---|---|---|---|
| 1 | Atomic oxygen in low Earth orbit | On the MISSE 2 flight PMMA had an erosion yield above 5.60e-24 cm3/atom (a lower bound, because samples eroded through), against 3.00e-24 for Kapton H in the same table. Fluoropolymers were far lower, for example FEP at 2.00e-25 and PTFE at 1.42e-25. | flight MISSE 2, 3.95 yr, fluence 8.43e21 atoms/cm2 |
| 2 | Ultraviolet light (ground sunlight test, in air) | UV-transmitting acrylic samples from different makers behaved very differently: Reynolds sample 17 lost 47.5% of its transmittance at 360 nm, while Polycast sample 18 changed by +1.8%. The paper links UV damage in PMMA to main-chain scission and detachment of side-groups, with a new absorption band peaking at 285 nm, and says commercial acrylics usually carry UV absorbers. | exposure outdoor sunlight, Madison, Wisconsin, August to September 2008dose 296 J/cm2 total UV for the worst sample in the short-term test |
| 3 | Gamma radiation (ground, cobalt-60) | A new absorption band between 384 and 523 nm appeared at every dose tested (10, 50, 100 and 500 kGy), meaning the clear foils took on colour. The authors attribute this to colour centres and describe cross-linking up to about 100 kGy and chain scission and carbonyl group loss at higher doses. | source cobalt-60, 2 kGy/h, room temperaturespecimen CLAREX PMMA foils 200 and 500 micrometres |
| 4 | Water, immersion | The maximum weight gain during immersion is 2.1% for PLEXIGLAS GS and XT. The manufacturer also lists good resistance to diluted acids and to alkalis and limited resistance to organic solvents. | test standard ISO 62, Method 1grade PLEXIGLAS GS 0F00; 0Z09 |
Risks and side effects
Hazards to people, what happens when a cell overheats, and how the material is handled and stored.
For people
A PMMA safety data sheet does not classify the polymer as hazardous, but it is a combustible plastic and the data come from a powder standard, not a spacecraft sheet.
- The solid
- The Resonac safety data sheet (1 July 2023) for a PMMA powder lists no hazard statements, no exposure limit value and 'no known significant effects or critical hazards'. It does not cover sheet products.
- Fire
- The manufacturer says the sheet burns more or less like hardwood with very little smoke, and lists an ignition temperature of 425 °C. The safety data sheet names carbon dioxide and carbon monoxide as combustion products.
- Dust
- For the powder a P2 particle filter and safety glasses with side protection are recommended where dust is a risk.
If it fails
These results are from flight exposure and laboratory tests on films, foils and sheet, not from failures of finished spacecraft parts.
- In orbit
- On the ISS, PMMA eroded under atomic oxygen faster than Kapton H, and in places it eroded through, so NASA could report only a lower bound of above 5.60 × 10⁻²⁴ cm³/atom.
- Under ultraviolet light
- In a ground sunlight test on acrylic without a UV absorber, the worst sample lost 47.5% of its transmittance at 360 nm after 296 J/cm². Another maker's sample changed by +1.8% at 263 J/cm², so the result depends on the product.
- Under gamma radiation
- PMMA foils irradiated with cobalt-60 gamma rays at 10, 50, 100 and 500 kGy developed a new visible absorption band, so the clear plastic took on colour.
Handling and storage
- Storage
- For the powder, store in the original container, out of direct sunlight, in a dry, cool, well-ventilated area, away from oxidizing agents.
- Heat
- Keep away from heat, sparks and flame. The sheet's permanent service temperature is 80 °C for the cast grade and tensile strength halves between 23 °C and 70 °C.
- Sunlight before use
- For UV-transmitting acrylic the authors of the ultraviolet study advise covered storage and blocking direct sunlight.
Test details
The original wording and numbers from the sources, for readers who want them.
Failure risks
| Failure | Trigger and consequence |
|---|---|
| Erosion by atomic oxygen in low Earth orbithigh severity | 3.95 years on the ISS exterior at a fluence of 8.43e21 atoms/cm2PMMA eroded through in places on the MISSE 2 flight, so only a lower bound (above 5.60e-24 cm3/atom) of its erosion yield could be measured. |
| Loss of clarity under ultraviolet lightmoderate severity | Strong UV exposure of acrylic without a UV absorber (ground sunlight test, 296 J/cm2)Transmittance at 360 nm fell by 47.5% in the worst sample, with tails of the absorption band extending toward visible wavelengths. |
| Colouring under gamma radiationmoderate severity | Cobalt-60 gamma doses of 10 to 500 kGyA new visible absorption band from 384 to 523 nm appeared in 200 and 500 micrometre foils. |
| Softening and loss of strength when warmmoderate severity | Temperature above the manufacturer's service limitTensile strength of PLEXIGLAS GS falls from 80 MPa at 23 degC to 40 MPa at 70 degC, and the permanent service limit is 80 degC. |
Side effects on surrounding parts
| Affects | Effect |
|---|---|
| Nearby optics and sensors (contamination risk) | Outgassing in vacuum can deposit films on nearby surfaces. The NASA database entries for acrylic sheet show total mass loss of 0.51 to 0.81% and collected volatile condensable material of 0 to 0.05%, all inside the NASA screening limits of 1.0% and 0.10%. |
Handling and storage
- For the powder: store in the original container, protected from direct sunlight, in a dry, cool, well-ventilated area, away from oxidizing agents. Keep away from heat, sparks and flame. Wear safety glasses with side protection; a P2 particle filter is recommended if dust is a risk.
- The manufacturer lists the sheet as easy to work, bondable and thermoformable, with forming temperatures of 160 to 175 degC for GS.
Mitigations
- UV-absorbing grades exist; the manufacturer's GS 0F00 grade is marked as largely UV-absorbing, and the Littlejohn paper recommends covered storage and blocking direct sunlight for UV-transmitting acrylic.
Supply and geography
How common the raw materials are and where they come from.
Feedstock route (acetone cyanohydrin, the principal route)
Acetone and hydrogen cyanide form acetone cyanohydrin, which sulfuric acid hydrolyses to an ester adduct and methanolysis gives MMA and ammonium bisulfate. The ACH route co-produces about 1.1 kg of ammonium bisulfate per kg of MMA; the ammonium bisulfate can be converted to ammonium sulfate, a fertiliser.
- Recycling
- Not sourced.
- Substitutes
- Other routes named in the same article: isobutylene (Asahi Chemical direct oxidative esterification of methacrolein; an isobutylene process commercialised by Escambia Co.) and ethylene to methyl propionate, with a one-step Shell process from methyl acetylene at 99% yield.
Volume
The article states that the ACH technology affords more than 3 billion kilograms of MMA per year and that its economics have been optimized. The year of the figure is not given and no producer share is printed.
- Top producers
- Escambia Co., Asahi Chemical
- Recycling
- Not sourced.
Documents
Datasheets, safety data sheets, papers and standards you can open.
Full record
The complete spore, as stored. Free to reuse under CC-BY-4.0. Images keep the licence shown with each one.
Show the full YAML
spore: profile
id: pmma
spore_version: 0.2
family: engineering-polymers
name: Poly(methyl methacrylate)
abbreviation: PMMA
role: transparent structural/optical polymer (acrylic)
category: polymers
type: acrylics
summary: |
PMMA, also called acrylic or Plexiglas, is a clear, rigid thermoplastic. A manufacturer datasheet gives the cast sheet grade a density of 1.19 g/cm3, a tensile strength of 80 MPa at 23 degC, a Vicat softening temperature of 115 degC and about 92% light transmittance. In low Earth orbit it erodes under atomic oxygen faster than Kapton H (above 5.60e-24 against 3.00e-24 cm3/atom on the MISSE 2 flight), and ground tests show that ultraviolet light and gamma rays discolour it. NASA outgassing database entries for acrylic sheet show total mass loss of 0.51 to 0.81%.
best_for: A clear, rigid, easily shaped plastic for windows, lenses and covers (about 92% transmittance, refractive index 1.491) with low outgassing in the NASA database entries (0.51 to 0.81% mass loss)
weakest_at: Atomic oxygen in low Earth orbit (eroded faster than Kapton H), ultraviolet light in grades without a UV absorber, and heat (maximum permanent service temperature about 80 degC)
identity:
formula: (C5H8O2)n
cas: 9011-14-7
source: shodex-sds
where: Section 1.1 (CAS number 9011-14-7, chemical formula (C5-H8-O2)x) and Section 3.1; repeat unit C5H8O2 also in Banks et al. Table in the appendix listing repeat unit formulas
tags:
environments:
- low-earth-orbit
stresses:
- atomic-oxygen
- uv
- vacuum-and-outgassing
- total-radiation-dose
- thermal-cycling
applications:
- optics-and-cameras
- structures
properties:
- benchmark: density
label: Density, PLEXIGLAS GS (cast sheet)
value: 1.19
unit: g/cm3
scope: material
conditions:
grade: PLEXIGLAS GS 0F00; 0Z09 (cast)
test_standard: ISO 1183
temperature: 23 degC
humidity: 50% relative humidity
method: Typical value listed in the manufacturer's technical information
status: ground
note: Extruded PLEXIGLAS XT also lists 1.19 g/cm3. NASA's MISSE 2 report uses 1.1628 g/cm3 for PMMA (Table II). A PMMA safety data sheet gives a relative density of 1.15 to 1.19.
source: plexiglas-211
where: Typical property values, Mechanical properties table (page 4 of 7)
- benchmark: tensile_strength
label: Tensile strength at 23 degC, PLEXIGLAS GS
value: 80
unit: MPa
scope: material
conditions:
grade: PLEXIGLAS GS 0F00; 0Z09 (cast)
test_standard: ISO 527-2/1B/5
temperature: 23 degC
humidity: 50% relative humidity
method: Typical value listed in the manufacturer's technical information
status: ground
note: The same table gives 110 MPa at -40 degC and 40 MPa at 70 degC for GS. Extruded PLEXIGLAS XT gives 72 MPa at 23 degC. Elongation at break is 5.5% for GS (ISO 527-2/1B/5).
source: plexiglas-211
where: Mechanical properties table (page 4 of 7)
- benchmark: tensile_modulus
label: Modulus of elasticity (short-term), PLEXIGLAS GS
value: 3300
unit: MPa
scope: material
conditions:
grade: PLEXIGLAS GS 0F00; 0Z09 (cast)
test_standard: ISO 527-2/1B/1
temperature: 23 degC
humidity: 50% relative humidity
method: Typical value listed in the manufacturer's technical information
status: ground
note: PLEXIGLAS XT also lists 3300 MPa. Flexural strength of GS is 115 MPa (ISO 178) and Poisson's ratio 0.37 (ISO 527-1).
source: plexiglas-211
where: Mechanical properties table (page 4 of 7)
- benchmark: vicat_softening_temp
label: Vicat softening temperature, PLEXIGLAS GS
value: 115
unit: degC
scope: material
conditions:
grade: PLEXIGLAS GS 0F00; 0Z09 (cast)
test_standard: ISO 306, Method B 50
method: Typical value listed in the manufacturer's technical information
status: ground
note: A softening point, not a glass transition temperature. PLEXIGLAS XT lists 103 degC. Heat deflection temperature at 1.8 MPa is given as 105; 107 degC for the GS grades 0F00; 0Z09 (ISO 75). No glass transition temperature was read from an opened source.
source: plexiglas-211
where: Thermal properties table (page 5 of 7)
- benchmark: max_service_temp
label: Maximum permanent service temperature, PLEXIGLAS GS
value: 80
unit: degC
scope: material
conditions:
grade: PLEXIGLAS GS 0F00; 0Z09 (cast)
basis: permanent (long-term) use in air; no test standard given
method: Value listed by the manufacturer
status: ground
note: PLEXIGLAS XT (extruded) is listed at 70 degC. Ground value in air, not a vacuum or orbit rating.
source: plexiglas-211
where: Thermal properties table (page 5 of 7); page 1 summary
- benchmark: cte
label: Coefficient of linear thermal expansion, PLEXIGLAS GS
value: 0.00007
unit: 1/K
scope: material
conditions:
grade: PLEXIGLAS GS 0F00; 0Z09 (cast)
test_standard: DIN 53752-A
temperature_range: 0 to 50 degC
method: Typical value listed in the manufacturer's technical information (written as 7 x 10-5, equal to 0.07 mm/m per degC)
status: ground
source: plexiglas-211
where: Thermal properties table (page 5 of 7)
- benchmark: thermal_conductivity
label: Thermal conductivity, PLEXIGLAS GS
value: 0.19
unit: W/(m K)
scope: material
conditions:
grade: PLEXIGLAS GS 0F00; 0Z09 (cast)
test_standard: DIN 52612
method: Typical value listed in the manufacturer's technical information
status: ground
note: Specific heat is listed as 1.47 J/(g K); the table gives no test standard for it.
source: plexiglas-211
where: Thermal properties table (page 5 of 7)
- benchmark: light_transmittance_tau_d65
label: Light transmittance (tau D65), PLEXIGLAS GS
value: 92
unit: '%'
scope: material
conditions:
grade: PLEXIGLAS GS 0F00; 0Z09 (cast)
test_standard: DIN 5036, Part 3
light: D65 illuminant, visible range
method: Typical value listed in the manufacturer's technical information (printed as ~ 92)
status: ground
note: The table lists a reflection loss of 4% per surface in the visible range and total energy transmittance of 85% (DIN EN 410). The grade is marked UV-absorbing (the table lists no under UV transmission); the extruded XT 0A070 grade is UV transmitting. Sheet thickness for the transmittance value is not stated.
source: plexiglas-211
where: Optical properties table (page 6 of 7)
- benchmark: refractive_index_nd20_plexiglas_gs
label: Refractive index nD20, PLEXIGLAS GS
value: 1.491
unit: dimensionless
scope: material
conditions:
grade: PLEXIGLAS GS 0F00; 0Z09 (cast)
test_standard: ISO 489
temperature: 20 degC
wavelength: sodium D line (nD)
method: Typical value listed in the manufacturer's technical information
status: ground
source: plexiglas-211
where: Optical properties table (page 6 of 7)
- benchmark: maximum_water_weight_gain_during
label: Maximum water weight gain during immersion, PLEXIGLAS GS
value: 2.1
unit: '% mass'
scope: material
conditions:
grade: PLEXIGLAS GS 0F00; 0Z09 (cast)
test_standard: ISO 62, Method 1
state: immersion in water, specimen 60 x 60 x 2 mm3
method: Typical value listed in the manufacturer's technical information
status: ground
note: Water absorption in 24 h at 23 degC from the dry state is 41 mg for the same specimen. Acrylic can release absorbed water in vacuum, which matters for outgassing.
source: plexiglas-211
where: Behaviour towards water table (page 7 of 7)
- benchmark: atomic_oxygen_erosion_yield
value: 5.6e-24
bound: lower
unit: cm3/atom
scope: material
conditions:
experiment: MISSE 2 PEACE polymers, exterior of the International Space Station (PEC 2 tray 1, Quest airlock)
exposure: 3.95 yr in low Earth orbit, 16 August 2001 to 30 July 2005
comparison: Kapton H polyimide measured 3.00e-24 cm3/atom in the same table
method: Mass-loss erosion yield from the MISSE 2 flight samples (the report notes that for some stacked thin-film samples part or all of the area eroded through, so the listed yield is a lower bound, shown as greater than 5.60e-24)
status: flight
note: Density used for PMMA in the report is 1.1628 g/cm3 and ash fraction 2.80e-4 (Table II). The report's predictive tool gives 5.65e-24 cm3/atom for PMMA (Table VII). For comparison the same table has FEP at 2.00e-25 and PTFE at 1.42e-25 cm3/atom.
source: banks2008
where: Table I; Table II for density and ash fraction; Table VII for the predicted value; Section 2.1 for exposure
- benchmark: outgassing_tml
label: Total mass loss, PLEXIGLAS G acrylic sheet (NASA database entry GSC29989)
value: 0.81
unit: '% mass'
scope: material
conditions:
material: PLEXIGLAS G ACRYLIC SHEET
database_id: GSC29989
manufacturer_code: ARK
usage: sheet
test_method: 'NASA outgassing screening test: 125 degC for 24 h in vacuum, ASTM E 595 (stated for the database in RP-1124 Rev. 4)'
method: Value from the NASA Goddard outgassing database (data file as mirrored in the Wolfram Data Repository, NASA 'Outgassing Db' dated 19 November 2015)
status: ground
note: Collected volatile condensable material is 0% and water vapour regained 0.29% for the same entry. The database file does not state the test conditions per entry; the 125 degC, 24 h conditions come from the NASA report describing the database. Other acrylic sheet entries are given in the following properties.
source: nasa-outgassing-db
where: Row GSC29989 (category Films and Sheet Materials), columns TML, CVCM, WVR
- benchmark: outgassing_cvcm
label: Collected volatile condensable material, PLEXIGLAS G acrylic sheet (NASA database entry GSC29989)
value: 0
unit: '% mass'
scope: material
conditions:
material: PLEXIGLAS G ACRYLIC SHEET
database_id: GSC29989
manufacturer_code: ARK
test_method: 'NASA outgassing screening test: 125 degC for 24 h in vacuum, ASTM E 595 (stated for the database in RP-1124 Rev. 4)'
method: Value from the NASA Goddard outgassing database (data file as mirrored in the Wolfram Data Repository, NASA 'Outgassing Db' dated 19 November 2015)
status: ground
note: The database lists 0 percent, which means below its reporting resolution, not necessarily exactly zero. The NASA screening limits quoted in RP-1124 are 1.0 percent TML and 0.10 percent CVCM.
source: nasa-outgassing-db
where: Row GSC29989, column CVCM
- benchmark: total_mass_loss_plexiglas_11_uva
label: Total mass loss, PLEXIGLAS 11 UVA lens material (NASA database entry GSFC0460)
value: 0.57
unit: '% mass'
scope: material
conditions:
material: PLEXIGLAS 11 UVA
database_id: GSFC0460
manufacturer_code: ROH
usage: lens
test_method: 'NASA outgassing screening test: 125 degC for 24 h in vacuum, ASTM E 595 (stated for the database in RP-1124 Rev. 4)'
method: Value from the NASA Goddard outgassing database (data file as mirrored in the Wolfram Data Repository)
status: ground
note: CVCM is 0%; water vapour regained is not available for this entry. A second PLEXIGLAS entry, VS-100 OPTICAL (GSFC0463), has TML 1% and CVCM 0.01%.
source: nasa-outgassing-db
where: Row GSFC0460, columns TML and CVCM
- benchmark: total_mass_loss_acrylite_acrylic
label: Total mass loss, ACRYLITE acrylic sheet (NASA database entry GSFC0915)
value: 0.51
unit: '% mass'
scope: material
conditions:
material: ACRYLITE ACRYLIC SHEET
database_id: GSFC0915
manufacturer_code: ACC
usage: structural
test_method: 'NASA outgassing screening test: 125 degC for 24 h in vacuum, ASTM E 595 (stated for the database in RP-1124 Rev. 4)'
method: Value from the NASA Goddard outgassing database (data file as mirrored in the Wolfram Data Repository)
status: ground
note: CVCM is 0.05%; water vapour regained is not available for this entry.
source: nasa-outgassing-db
where: Row GSFC0915, columns TML and CVCM
- benchmark: total_mass_loss_acrylic_safety
label: Total mass loss, acrylic safety glazing, polymethylmethacrylate (NASA database entry GSC28432)
value: 0.68
unit: '% mass'
scope: material
conditions:
material: ACRYLIC SAFETY GLAZING - POLYMETHOLMETHACRYLATE (spelling as in the database)
database_id: GSC28432
manufacturer_code: PTC
usage: glazing
test_method: 'NASA outgassing screening test: 125 degC for 24 h in vacuum, ASTM E 595 (stated for the database in RP-1124 Rev. 4)'
method: Value from the NASA Goddard outgassing database (data file as mirrored in the Wolfram Data Repository)
status: ground
note: CVCM is 0% and water vapour regained 0.27% for the same entry.
source: nasa-outgassing-db
where: Row GSC28432, columns TML, CVCM and WVR
- benchmark: transmittance_change_at_360_nm_after
label: Transmittance change at 360 nm after solar UV exposure, UV-transmitting acrylic (Reynolds sample 17)
value: -47.5
unit: '% change in transmittance'
scope: material
conditions:
specimen: Reynolds Polymer Technology UV-transmitting (UVT) cast acrylic, 9.5 mm path, polished
exposure: outdoor sunlight in Madison, Wisconsin, 7 exposures of 3 to 4 hours, total 296 J/cm2 of UV
wavelength: 360 nm
environment: Earth air, not vacuum
method: UV-Vis spectrophotometer transmittance before and after exposure (change from unexposed sample)
status: ground
note: A ground sunlight test on detector-grade acrylic without a UV absorber, not a space test. The same table gives +1.8% for Polycast sample 18 (263 J/cm2) and -3.2% for YenNan sample 19 (181 J/cm2); changes under 4% cannot be resolved. In 14 to 25 day exposures Polycast sample 7 lost 13.8% at 2192 J/cm2 (Table 3). Commercial acrylics normally contain UV absorbers, which the paper says boost stability.
source: littlejohn2009
where: Table 2; Table 3; Section 1
- benchmark: highest_gamma_dose_in_an_optical_and
label: Highest gamma dose in an optical and infrared study of PMMA foils
value: 500
unit: kGy
scope: material
conditions:
source_of_radiation: cobalt-60 gamma source, dose rate 2 kGy/h
doses: 10, 50, 100 and 500 kGy
specimen: CLAREX PMMA foils, 200 and 500 micrometres thick (Nitto Jushi Kogyo)
temperature: room temperature
measurement: UV-Vis transmission 200 to 1100 nm and FTIR
method: Optical absorption (transmission) and FTIR spectra before and after irradiation
status: ground
note: A dose tested, not a tolerance limit. All doses created a new absorption band from 384 to 523 nm in the visible range (colour centres); it was strongest at 10 and 500 kGy and weaker at 50 and 100 kGy. The authors see cross-linking up to about 100 kGy and carbonyl group loss and chain scission dominating beyond it.
source: rai2016
where: Abstract; Section 2; Section 3.2
corrosion:
- environment: Atomic oxygen in low Earth orbit
headline: Atomic oxygen eroded PMMA faster than Kapton H polyimide on the ISS.
effect: On the MISSE 2 flight PMMA had an erosion yield above 5.60e-24 cm3/atom (a lower bound, because samples eroded through), against 3.00e-24 for Kapton H in the same table. Fluoropolymers were far lower, for example FEP at 2.00e-25 and PTFE at 1.42e-25.
rating: severe
conditions:
flight: MISSE 2, 3.95 yr, fluence 8.43e21 atoms/cm2
source: banks2008
where: Table I; Section 2.1
- environment: Ultraviolet light (ground sunlight test, in air)
headline: Some acrylic without a UV absorber lost nearly half its transmittance at 360 nm after 296 J/cm2 of sunlight.
effect: 'UV-transmitting acrylic samples from different makers behaved very differently: Reynolds sample 17 lost 47.5% of its transmittance at 360 nm, while Polycast sample 18 changed by +1.8%. The paper links UV damage in PMMA to main-chain scission and detachment of side-groups, with a new absorption band peaking at 285 nm, and says commercial acrylics usually carry UV absorbers.'
rating: moderate
conditions:
exposure: outdoor sunlight, Madison, Wisconsin, August to September 2008
dose: 296 J/cm2 total UV for the worst sample in the short-term test
source: littlejohn2009
where: Table 2; Section 1
- environment: Gamma radiation (ground, cobalt-60)
headline: Gamma doses from 10 to 500 kGy made PMMA foils absorb visible light.
effect: A new absorption band between 384 and 523 nm appeared at every dose tested (10, 50, 100 and 500 kGy), meaning the clear foils took on colour. The authors attribute this to colour centres and describe cross-linking up to about 100 kGy and chain scission and carbonyl group loss at higher doses.
rating: moderate
conditions:
source: cobalt-60, 2 kGy/h, room temperature
specimen: CLAREX PMMA foils 200 and 500 micrometres
source: rai2016
where: Abstract; Section 3.2
- environment: Water, immersion
headline: PMMA sheet takes up a little water, a maximum of 2.1% of its mass on immersion.
effect: The maximum weight gain during immersion is 2.1% for PLEXIGLAS GS and XT. The manufacturer also lists good resistance to diluted acids and to alkalis and limited resistance to organic solvents.
rating: low
conditions:
test_standard: ISO 62, Method 1
grade: PLEXIGLAS GS 0F00; 0Z09
source: plexiglas-211
where: Behaviour towards water table (page 7 of 7); page 1 summary
risks:
hazards:
- text: 'A PMMA safety data sheet (Resonac Shodex STANDARD M-75, version 1.3, 1 July 2023, CAS 9011-14-7) says the product is not classified as hazardous under EU CLP: no signal word and no hazard statements. It is a PMMA powder sold as a chromatography standard, not sheet; it lists no exposure limit value and reports ''no known significant effects or critical hazards''.'
ghs: []
source: shodex-sds
where: Sections 2 and 8
- text: The sheet burns more or less like hardwood with very little smoke; the manufacturer lists an ignition temperature of 425 degC for PLEXIGLAS GS (DIN 51794), smoke gas toxicity 'none' and building material class B2. The safety data sheet names carbon dioxide and carbon monoxide as decomposition products in a fire.
ghs: []
source: plexiglas-211
where: Thermal properties table (page 5 of 7); page 1 summary
failure_risks:
- mode: Erosion by atomic oxygen in low Earth orbit
trigger: 3.95 years on the ISS exterior at a fluence of 8.43e21 atoms/cm2
consequence: PMMA eroded through in places on the MISSE 2 flight, so only a lower bound (above 5.60e-24 cm3/atom) of its erosion yield could be measured.
severity: high
source: banks2008
where: Table I; Section 2.1
- mode: Loss of clarity under ultraviolet light
trigger: Strong UV exposure of acrylic without a UV absorber (ground sunlight test, 296 J/cm2)
consequence: Transmittance at 360 nm fell by 47.5% in the worst sample, with tails of the absorption band extending toward visible wavelengths.
severity: moderate
source: littlejohn2009
where: Table 2; Section 5
- mode: Colouring under gamma radiation
trigger: Cobalt-60 gamma doses of 10 to 500 kGy
consequence: A new visible absorption band from 384 to 523 nm appeared in 200 and 500 micrometre foils.
severity: moderate
source: rai2016
where: Section 3.2
- mode: Softening and loss of strength when warm
trigger: Temperature above the manufacturer's service limit
consequence: Tensile strength of PLEXIGLAS GS falls from 80 MPa at 23 degC to 40 MPa at 70 degC, and the permanent service limit is 80 degC.
severity: moderate
source: plexiglas-211
where: Mechanical properties table (page 4 of 7); thermal properties table (page 5 of 7)
side_effects:
- text: Outgassing in vacuum can deposit films on nearby surfaces. The NASA database entries for acrylic sheet show total mass loss of 0.51 to 0.81% and collected volatile condensable material of 0 to 0.05%, all inside the NASA screening limits of 1.0% and 0.10%.
affects: Nearby optics and sensors (contamination risk)
source: nasa-outgassing-db
where: Rows GSC29989, GSFC0460, GSFC0915 and GSC28432
handling:
- text: 'For the powder: store in the original container, protected from direct sunlight, in a dry, cool, well-ventilated area, away from oxidizing agents. Keep away from heat, sparks and flame. Wear safety glasses with side protection; a P2 particle filter is recommended if dust is a risk.'
source: shodex-sds
where: Sections 7.2, 8.2 and 10
- text: The manufacturer lists the sheet as easy to work, bondable and thermoformable, with forming temperatures of 160 to 175 degC for GS.
source: plexiglas-211
where: Page 1 summary; thermal properties table (page 5 of 7)
mitigations:
- text: UV-absorbing grades exist; the manufacturer's GS 0F00 grade is marked as largely UV-absorbing, and the Littlejohn paper recommends covered storage and blocking direct sunlight for UV-transmitting acrylic.
source: plexiglas-211
where: Survey of grades (page 2 of 7)
uses:
- application: optics-and-cameras
device: Lens and window material listed in the NASA outgassing database
example: The NASA outgassing database lists PLEXIGLAS 11 UVA and PLEXIGLAS VS-100 OPTICAL with the usage 'lens' and acrylic safety glazing with the usage 'glazing'. The database does not say which spacecraft used them.
source: nasa-outgassing-db
where: Rows GSFC0460, GSFC0463 and GSC28432
- application: structures
device: Aircraft glazing grades (ground and aviation use, not spacecraft)
example: The manufacturer lists PLEXIGLAS GS 241, 245 and 249 as special grades approved for aircraft glazing, UV-absorbing and of high optical quality.
source: plexiglas-211
where: Survey of grades (page 2 of 7)
- application: optics-and-cameras
device: Flight sample on the ISS exterior (MISSE 2 PEACE experiment)
example: PMMA was one of the 41 polymer samples flown on the ISS exterior from 16 August 2001 to 30 July 2005 to measure atomic oxygen erosion.
source: banks2008
where: Section 2.1; Table I
documents:
- title: 'PLEXIGLAS Solid sheet, block, multi-skin sheet, corrugated sheet, tube and rod: technical information (Ref. No. 211-1, 04/25)'
type: datasheet
url: https://www.voskunststoffen.nl/files/166151/datasheet%20plexiglas%20XT%20GS.pdf
year: 2025
- title: 'NASA/TM-2008-215490: Atomic Oxygen Erosion Yield Predictive Tool for Spacecraft Polymers in Low Earth Orbit'
type: report
url: https://ntrs.nasa.gov/citations/20090011780
year: 2008
- title: 'NASA Reference Publication 1124 Revision 4: Outgassing Data for Selecting Spacecraft Materials'
type: report
url: https://ntrs.nasa.gov/citations/19970027853
year: 1997
- title: Spacecraft Materials Outgassing Data (NASA Outgassing Db as Wolfram Data Repository resource)
type: database
url: https://datarepository.wolframcloud.com/resources/Outgassing/
year: 2015
- title: UV Degradation of the Optical Properties of Acrylic for Neutrino and Dark Matter Experiments (arXiv:0907.3706)
type: paper
url: https://arxiv.org/abs/0907.3706
year: 2009
- title: Optical properties (UV-Vis and FTIR) of gamma irradiated polymethyl methacrylate (arXiv:1611.02129)
type: paper
url: https://arxiv.org/abs/1611.02129
year: 2016
- title: 'Safety data sheet: Shodex STANDARD M-75 (PMMA, Resonac, version 1.3, 1 July 2023)'
type: sds
url: https://www.shodex.de/_files/ugd/55774d_39c47243186a47b38d9fcf202ced8e32.pdf
year: 2023
- title: 'NIST: Atomic Weights and Isotopic Compositions for All Elements (elements C, H and O)'
type: database
url: https://physics.nist.gov/cgi-bin/Compositions/stand_alone.pl?ele=C&all=all
year: 2026
- title: 'PubChem: Methyl Methacrylate, CID 6658 (property record)'
type: database
url: https://pubchem.ncbi.nlm.nih.gov/compound/6658
year: 2026
gaps:
- NASA outgassing database (outgassing.nasa.gov / etd.gsfc.nasa.gov) is an interactive search page and could not be queried here; the NASA values come from a public-domain copy of the database dated 19 November 2015 in the Wolfram Data Repository. The per-entry test conditions are not stated in that copy, so the 125 degC, 24 h conditions are taken from RP-1124 Rev. 4's description of the database. The scanned RP-1124 tables could not be read, so the entries were not cross-checked against the report.
- 'No glass transition temperature from an opened source: the Netzsch polymer database page returned HTTP 403 and Rigaku''s DSC note was not read. The Vicat softening temperature (115 degC) is entered instead and is not the same quantity.'
- No PMMA flight result for ultraviolet or radiation effects in orbit was found. The ultraviolet and gamma values are ground tests (sunlight on Earth; cobalt-60), and no electron or proton irradiation test of PMMA was found.
- Space-grade data for vacuum UV, thermal cycling and micrometeoroid effects on PMMA were not found; the MISSE 2 passport lists thermal cycling between -30 and 40 degC but no PMMA property change from it.
- Mechanical data at cryogenic and elevated temperatures other than the three tensile strength points in the PLEXIGLAS table (-40, 23 and 70 degC) were not found.
- 'No PubChem compound record or ECHA registration was read: PubChem returned a verification page and only the substance synonym list (SID 164812091, CAS 9011-14-7) was seen. Hazard data rest on one PMMA powder safety data sheet from a chromatography standard, not on a sheet or spacecraft-grade product. Sigma-Aldrich''s acrylic sheet SDS could not be opened.'
- The gamma study reports spectra rather than a single transmittance number per dose, and a Gonzalez 1996 compression study and an Ozdemir and Usanmaz 2009 tensile study (about 523 kGy) were seen only as database abstracts, so no mechanical radiation values are entered.
- The cast PLEXIGLAS GS datasheet values are typical values for sheet; no space-qualified PMMA grade, spaceflight specification or real mission use of PMMA was found in an opened source.
supply:
- subject: Feedstock route (acetone cyanohydrin, the principal route)
abundance: Acetone and hydrogen cyanide form acetone cyanohydrin, which sulfuric acid hydrolyses to an ester adduct and methanolysis gives MMA and ammonium bisulfate. The ACH route co-produces about 1.1 kg of ammonium bisulfate per kg of MMA; the ammonium bisulfate can be converted to ammonium sulfate, a fertiliser.
producers: []
critical_lists: []
recycling: Not sourced.
substitutes:
- 'Other routes named in the same article: isobutylene (Asahi Chemical direct oxidative esterification of methacrolein; an isobutylene process commercialised by Escambia Co.) and ethylene to methyl propionate, with a one-step Shell process from methyl acetylene at 99% yield.'
source: wiki-mma
where: 'Methyl methacrylate article, Production: Cyanohydrin route, Isobutylene routes and Methyl propionate routes sections'
- subject: Volume
abundance: The article states that the ACH technology affords more than 3 billion kilograms of MMA per year and that its economics have been optimized. The year of the figure is not given and no producer share is printed.
producers:
- name: Escambia Co.
note: Named as having commercialised the isobutylene route; no volume printed
country: Escambia Co.
- name: Asahi Chemical
note: Named as having developed the direct oxidative esterification route; no volume printed
country: Asahi Chemical
critical_lists: []
recycling: Not sourced.
substitutes: []
source: wiki-mma
where: 'Methyl methacrylate article, Production: Cyanohydrin route and Isobutylene routes sections'
sources:
plexiglas-211:
title: PLEXIGLAS Solid sheet, block, multi-skin sheet, corrugated sheet, tube and rod - Technical information (POLYVANTIS GmbH)
id: Ref. No. 211-1, 04/25 (copy hosted by a reseller, Vos Kunststoffen)
url: https://www.voskunststoffen.nl/files/166151/datasheet%20plexiglas%20XT%20GS.pdf
year: 2025
kind: datasheet
license: manufacturer document, linked not reproduced
banks2008:
title: Atomic Oxygen Erosion Yield Predictive Tool for Spacecraft Polymers in Low Earth Orbit
id: NASA/TM-2008-215490, NTRS 20090011780
url: https://ntrs.nasa.gov/citations/20090011780
year: 2008
kind: report
license: public domain (NASA)
nasa-outgassing-db:
title: Spacecraft Materials Outgassing Data (NASA Outgassing Db, 19 November 2015, as Wolfram Data Repository resource)
id: Wolfram Data Repository resource 'Spacecraft Materials Outgassing Data'; CSV object 4170f088-0bf1-4e1b-bbbe-56b9ca76eadf
url: https://datarepository.wolframcloud.com/resources/Outgassing/
year: 2015
kind: database
license: public domain (NASA data, as stated on the resource page)
nasa-rp1124:
title: Outgassing Data for Selecting Spacecraft Materials
id: NASA Reference Publication 1124 Revision 4, June 1997, NTRS 19970027853
url: https://ntrs.nasa.gov/citations/19970027853
year: 1997
kind: report
license: public domain (NASA)
littlejohn2009:
title: UV Degradation of the Optical Properties of Acrylic for Neutrino and Dark Matter Experiments
id: arXiv:0907.3706v1 (physics.ins-det), July 2009
url: https://arxiv.org/abs/0907.3706
year: 2009
kind: paper
license: arXiv preprint, linked not reproduced
rai2016:
title: Optical properties (UV-Vis and FTIR) of gamma irradiated polymethyl methacrylate (PMMA)
id: arXiv:1611.02129
url: https://arxiv.org/abs/1611.02129
year: 2016
kind: paper
license: arXiv preprint, linked not reproduced
shodex-sds:
title: 'Safety Data Sheet: Shodex STANDARD M-75 (polymethyl methacrylate, Resonac)'
id: SD-051DE-EN, version 1.3, date of revision 01/07/2023
url: https://www.shodex.de/_files/ugd/55774d_39c47243186a47b38d9fcf202ced8e32.pdf
year: 2023
kind: datasheet
license: manufacturer document, linked not reproduced
wiki-pmma:
title: Poly(methyl methacrylate)
id: Wikipedia article (fetched 2026-10-15); sections Production, Cast acrylic, Extruded acrylic
url: https://en.wikipedia.org/wiki/Poly(methyl_methacrylate)
year: 2026
kind: web
license: CC BY-SA 4.0 (Wikipedia), linked not reproduced
wiki-mma:
title: Methyl methacrylate
id: Wikipedia article (fetched 2026-10-15); sections Production, Cyanohydrin route, Isobutylene routes, Methyl propionate routes
url: https://en.wikipedia.org/wiki/Methyl_methacrylate
year: 2026
kind: web
license: CC BY-SA 4.0 (Wikipedia), linked not reproduced
pubchem-mma:
title: Methyl Methacrylate, PubChem compound record (PUG REST property table)
id: CID 6658; MolecularFormula C5H8O2; MolecularWeight 100.12
url: https://pubchem.ncbi.nlm.nih.gov/compound/6658
year: 2026
kind: database
license: public domain (PubChem)
nist-atomic-weights:
title: 'Atomic Weights and Isotopic Compositions for All Elements (standard atomic weights: C [12.0096, 12.0116]; H [1.00784, 1.00811]; O [15.99903, 15.99977])'
id: NIST Physical Measurement Laboratory, element pages C, H and O
url: https://physics.nist.gov/cgi-bin/Compositions/stand_alone.pl?ele=C&all=all
kind: database
license: public domain (NIST)
license: CC-BY-4.0
updated: '2026-10-17'
review:
status: draft
method: assistant
checked_values: 18
unreachable: 6
caveats: 9
note: Written by an AI assistant on 2026-10-17. All values were read in text extracted from the source PDFs or from the NASA outgassing data file (CSV), not from memory. Six sources could not be used (NASA outgassing search page, Netzsch polymer database, DTIC UV report, Nature gamma paper, PubChem compound page, Sigma-Aldrich SDS). Outgassing values come from a copy of the NASA database. Several values carry caveats noted in the file.
story:
recipe:
line: PMMA is made by polymerising the methyl methacrylate (MMA) monomer, C5H8O2, with radical initiation; anionic and living routes are also used, and emulsion, solution and bulk processes are routine (Wikipedia, Poly(methyl methacrylate), Production). Cast sheet, the highest-quality grade, is made by casting MMA mixed with initiators and possibly other additives into a form or mold, so polymerisation and moulding happen together. Extruded acrylic is made by melting solid acrylic pellets, and forcing them through dies (Wikipedia, Cast acrylic and Extruded acrylic). MMA itself is made mainly by the acetone cyanohydrin route (Wikipedia, Methyl methacrylate, Production).
parts:
- name: Methyl methacrylate
symbol: MMA
molar_mass: 100.12
role: Monomer; the repeat unit of PMMA has the same formula, C5H8O2 (PubChem CID 6658).
source: pubchem-mma
share_note: atoms C5H8O2
- name: Carbon
symbol: C
atoms: 5
atomic_weight: 12.0096
role: Element in the repeat unit. NIST standard atomic weight is printed as the interval [12.0096, 12.0116].
source: nist-atomic-weights
- name: Hydrogen
symbol: H
atoms: 8
atomic_weight: 1.00784
role: Element in the repeat unit. NIST standard atomic weight is printed as the interval [1.00784, 1.00811].
source: nist-atomic-weights
- name: Oxygen
symbol: O
atoms: 2
atomic_weight: 15.99903
role: Element in the repeat unit. NIST standard atomic weight is printed as the interval [15.99903, 15.99977].
source: nist-atomic-weights
risk_groups:
- title: For people
level: 1
verdict: Not classified as hazardous; the sheet burns
lead: A PMMA safety data sheet does not classify the polymer as hazardous, but it is a combustible plastic and the data come from a powder standard, not a spacecraft sheet.
points:
- label: The solid
line: The Resonac safety data sheet (1 July 2023) for a PMMA powder lists no hazard statements, no exposure limit value and 'no known significant effects or critical hazards'. It does not cover sheet products.
- label: Fire
line: The manufacturer says the sheet burns more or less like hardwood with very little smoke, and lists an ignition temperature of 425 °C. The safety data sheet names carbon dioxide and carbon monoxide as combustion products.
- label: Dust
line: For the powder a P2 particle filter and safety glasses with side protection are recommended where dust is a risk.
- title: If it fails
lead: These results are from flight exposure and laboratory tests on films, foils and sheet, not from failures of finished spacecraft parts.
points:
- label: In orbit
line: On the ISS, PMMA eroded under atomic oxygen faster than Kapton H, and in places it eroded through, so NASA could report only a lower bound of above 5.60 × 10⁻²⁴ cm³/atom.
- label: Under ultraviolet light
line: In a ground sunlight test on acrylic without a UV absorber, the worst sample lost 47.5% of its transmittance at 360 nm after 296 J/cm². Another maker's sample changed by +1.8% at 263 J/cm², so the result depends on the product.
- label: Under gamma radiation
line: PMMA foils irradiated with cobalt-60 gamma rays at 10, 50, 100 and 500 kGy developed a new visible absorption band, so the clear plastic took on colour.
- title: Handling and storage
points:
- label: Storage
line: For the powder, store in the original container, out of direct sunlight, in a dry, cool, well-ventilated area, away from oxidizing agents.
- label: Heat
line: Keep away from heat, sparks and flame. The sheet's permanent service temperature is 80 °C for the cast grade and tensile strength halves between 23 °C and 70 °C.
- label: Sunlight before use
line: For UV-transmitting acrylic the authors of the ultraviolet study advise covered storage and blocking direct sunlight.
why: 'Poly(methyl methacrylate), or PMMA, is a thermoplastic, a polymer that softens when heated and can be melted and reshaped. It is made by linking many small methyl methacrylate molecules into long chains, and each repeat unit has the formula C5H8O2. It is sold as acrylic and under trade names such as Plexiglas and Acrylite. The chains do not pack into crystals, so the plastic is clear: the cast sheet grade lets through about 92% of visible light and has a refractive index of 1.491, close to that of glass. It is also rigid, with a modulus of 3300 MPa, and light, with a density of 1.19 g/cm³. Its weakness is that it softens early (Vicat softening at 115 °C) and that its chains are easily broken by ultraviolet light, radiation and atomic oxygen. That makes it a good clear window or lens material on the ground, and a material that needs checking before use on the outside of a spacecraft.'
uses:
- where: Lens and window materials in the NASA outgassing database
line: The NASA outgassing database lists PLEXIGLAS 11 UVA and PLEXIGLAS VS-100 OPTICAL with the usage lens, and acrylic safety glazing with the usage glazing. The database does not say which spacecraft used them.
- where: Flown on the ISS as a test film
line: PMMA was one of 41 polymer samples flown on the outside of the ISS from 16 August 2001 to 30 July 2005 in the MISSE 2 PEACE experiment, to measure how fast atomic oxygen erodes each polymer.
- where: Aircraft glazing on the ground
line: The manufacturer lists three cast grades (PLEXIGLAS GS 241, 245 and 249) as approved for aircraft glazing. This is aviation use, not spacecraft use.
can_do:
- label: Strength and stiffness
value: 80 MPa
line: The cast PLEXIGLAS GS sheet has a tensile strength of 80 MPa at 23 °C (ISO 527-2) and a modulus of elasticity of 3300 MPa. Elongation at break is only 5.5%, so it is rigid and fairly brittle. Strength drops to 40 MPa at 70 °C.
- label: Clarity
value: About 92% transmittance
line: The manufacturer lists a light transmittance of about 92% and a refractive index of 1.491 for the cast grade. The grade is UV-absorbing, so it blocks ultraviolet light.
- label: Heat
value: Softens at 115 °C
line: The Vicat softening temperature is 115 °C and the maximum permanent service temperature is 80 °C. Thermal conductivity is 0.19 W/(m K), so it insulates, and thermal expansion is 7 × 10⁻⁵ per kelvin between 0 and 50 °C, much larger than metals or glass.
- label: In orbit
value: Erosion yield above 5.60e-24
line: On the MISSE 2 flight (3.95 years, fluence 8.43e21 atoms/cm²) PMMA lost material faster than Kapton H, 3.00 × 10⁻²⁴ cm³/atom. Because samples eroded through, 5.60 × 10⁻²⁴ cm³/atom is a lower bound.
- label: Outgassing
value: 0.51 to 0.81% mass loss
line: Outgassing is the release of trapped gases and volatile compounds in vacuum, which can then condense on optics and sensors. NASA database entries for acrylic sheet show total mass loss (TML) of 0.51 to 0.81% and collected volatile condensable material (CVCM) of 0 to 0.05%, inside the NASA screening limits of 1.0% and 0.10% for a 125 °C, 24 hour vacuum test.
compare: In low Earth orbit, PMMA eroded faster than Kapton H polyimide (above 5.60 × 10⁻²⁴ against 3.00 × 10⁻²⁴ cm³/atom in the same MISSE 2 table), while fluoropolymers such as FEP (2.00 × 10⁻²⁵) and PTFE (1.42 × 10⁻²⁵) eroded far less. On mass loss in vacuum, one Plexiglas entry (VS-100 OPTICAL) is listed at 1% TML, right at the NASA screening limit, so grade matters. No source in this record compares PMMA with glass, metals or composites, so no such comparison is made.
handling:
- The powder is not classified as hazardous by the supplier; store it dry and out of sunlight.
- Keep PMMA away from heat, sparks and flame; the sheet burns like hardwood.
- UV-transmitting acrylic should be stored covered and kept out of direct sunlight.
- A P2 dust filter and safety glasses with side protection are advised where there is powder or dust.
good_for:
- Clarity. The cast sheet transmits about 92% of visible light with a refractive index of 1.491.
- Low outgassing. NASA database entries for acrylic sheet show total mass loss of 0.51 to 0.81%.
- Light and rigid. Density is 1.19 g/cm³ and modulus 3300 MPa for the cast grade.
watch_out:
- Atomic oxygen. PMMA eroded faster than Kapton H on the ISS, and some samples eroded through.
- Ultraviolet light and radiation. A ground sunlight test cut transmittance at 360 nm by 47.5% in one sample, and gamma doses of 10 to 500 kGy added visible colour.
- Heat. Vicat softening is 115 °C and tensile strength falls from 80 MPa to 40 MPa between 23 °C and 70 °C.
- Thin evidence in space. No flight result for PMMA ultraviolet or radiation damage was found; those are ground tests.
verdict: PMMA is a clear, light, low-outgassing plastic that is a good window or lens material on the ground, but on the outside of a spacecraft in low Earth orbit it erodes under atomic oxygen faster than Kapton H, and ground tests show ultraviolet and gamma damage. It suits parts shielded from the orbital surface environment or protected by coatings, and no real mission use is documented in the sources read here.
compare_rows:
- scope: material
label: Density
benchmark: density
- scope: material
label: Thermal conductivity
benchmark: thermal_conductivity
- scope: material
label: Tensile strength
benchmark: tensile_strength
References
Every number above carries a reference number. Click one to see the source and where in it the value comes from.