{ "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%.\n", "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", "designations": [], "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, "bound": "exact", "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)", "source_detail": { "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" } }, { "benchmark": "tensile_strength", "label": "Tensile strength at 23 degC, PLEXIGLAS GS", "value": 80, "bound": "exact", "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)", "source_detail": { "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" } }, { "benchmark": "tensile_modulus", "label": "Modulus of elasticity (short-term), PLEXIGLAS GS", "value": 3300, "bound": "exact", "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)", "source_detail": { "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" } }, { "benchmark": "vicat_softening_temp", "label": "Vicat softening temperature, PLEXIGLAS GS", "value": 115, "bound": "exact", "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)", "source_detail": { "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" } }, { "benchmark": "max_service_temp", "label": "Maximum permanent service temperature, PLEXIGLAS GS", "value": 80, "bound": "exact", "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", "source_detail": { "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" } }, { "benchmark": "cte", "label": "Coefficient of linear thermal expansion, PLEXIGLAS GS", "value": 0.00007, "bound": "exact", "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)", "source_detail": { "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" } }, { "benchmark": "thermal_conductivity", "label": "Thermal conductivity, PLEXIGLAS GS", "value": 0.19, "bound": "exact", "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)", "source_detail": { "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" } }, { "benchmark": "light_transmittance_tau_d65", "label": "Light transmittance (tau D65), PLEXIGLAS GS", "value": 92, "bound": "exact", "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)", "source_detail": { "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" } }, { "benchmark": "refractive_index_nd20_plexiglas_gs", "label": "Refractive index nD20, PLEXIGLAS GS", "value": 1.491, "bound": "exact", "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)", "source_detail": { "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" } }, { "benchmark": "maximum_water_weight_gain_during", "label": "Maximum water weight gain during immersion, PLEXIGLAS GS", "value": 2.1, "bound": "exact", "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)", "source_detail": { "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" } }, { "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", "source_detail": { "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)" } }, { "benchmark": "outgassing_tml", "label": "Total mass loss, PLEXIGLAS G acrylic sheet (NASA database entry GSC29989)", "value": 0.81, "bound": "exact", "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", "source_detail": { "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)" } }, { "benchmark": "outgassing_cvcm", "label": "Collected volatile condensable material, PLEXIGLAS G acrylic sheet (NASA database entry GSC29989)", "value": 0, "bound": "exact", "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", "source_detail": { "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)" } }, { "benchmark": "total_mass_loss_plexiglas_11_uva", "label": "Total mass loss, PLEXIGLAS 11 UVA lens material (NASA database entry GSFC0460)", "value": 0.57, "bound": "exact", "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", "source_detail": { "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)" } }, { "benchmark": "total_mass_loss_acrylite_acrylic", "label": "Total mass loss, ACRYLITE acrylic sheet (NASA database entry GSFC0915)", "value": 0.51, "bound": "exact", "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", "source_detail": { "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)" } }, { "benchmark": "total_mass_loss_acrylic_safety", "label": "Total mass loss, acrylic safety glazing, polymethylmethacrylate (NASA database entry GSC28432)", "value": 0.68, "bound": "exact", "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", "source_detail": { "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)" } }, { "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, "bound": "exact", "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", "source_detail": { "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" } }, { "benchmark": "highest_gamma_dose_in_an_optical_and", "label": "Highest gamma dose in an optical and infrared study of PMMA foils", "value": 500, "bound": "exact", "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", "source_detail": { "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" } } ], "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" } ], "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": [ { "country": "Escambia Co." }, { "country": "Asahi Chemical" } ], "critical_lists": [], "recycling": "Not sourced.", "substitutes": [], "source": "wiki-mma", "where": "Methyl methacrylate article, Production: Cyanohydrin route and Isobutylene routes sections" } ], "media": [], "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." ], "story": { "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", "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.", "scope": "material", "value": "80 MPa" }, { "label": "Clarity", "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.", "scope": "material", "value": "About 92% transmittance" }, { "label": "Heat", "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.", "scope": "material", "value": "Softens at 115 °C" }, { "label": "In orbit", "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.", "scope": "material", "value": "Erosion yield above 5.60e-24" }, { "label": "Outgassing", "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.", "scope": "material", "value": "0.51 to 0.81% mass loss" } ], "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.", "compare_rows": [ { "label": "Density", "benchmark": "density", "scope": "material" }, { "label": "Thermal conductivity", "benchmark": "thermal_conductivity", "scope": "material" }, { "label": "Tensile strength", "benchmark": "tensile_strength", "scope": "material" } ], "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.", "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", "role": "Monomer; the repeat unit of PMMA has the same formula, C5H8O2 (PubChem CID 6658).", "share_note": "atoms C5H8O2", "source": "pubchem-mma" }, { "name": "Carbon", "symbol": "C", "role": "Element in the repeat unit. NIST standard atomic weight is printed as the interval [12.0096, 12.0116].", "atoms": 5, "atomic_weight": 12.0096, "source": "nist-atomic-weights" }, { "name": "Hydrogen", "symbol": "H", "role": "Element in the repeat unit. NIST standard atomic weight is printed as the interval [1.00784, 1.00811].", "atoms": 8, "atomic_weight": 1.00784, "source": "nist-atomic-weights" }, { "name": "Oxygen", "symbol": "O", "role": "Element in the repeat unit. NIST standard atomic weight is printed as the interval [15.99903, 15.99977].", "atoms": 2, "atomic_weight": 15.99903, "source": "nist-atomic-weights" } ] }, "risk_groups": [ { "title": "For people", "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." } ], "level": 1, "verdict": "Not classified as hazardous; the sheet burns" }, { "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." } ] } ] }, "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." }, "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", "url": "https://spacemushroom.com/profiles/pmma/" }