Hexcel IM7/8552 carbon-epoxy prepreg IM7/8552
Carbon fibre (IM7, 12K tow) reinforcement in an amine-cured, toughened epoxy matrix (HexPly 8552)
IM7/8552 is a carbon-epoxy prepreg made from Hexcel IM7 carbon fibre and HexPly 8552, an amine-cured, toughened epoxy matrix.
Evidence level
2 of 5
Lab-measured
- 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.
Stiffness
164 GPa
Strength
2724 MPa
Heat tolerance
200 °C dry, 154 °C wet
Service environment
121 °C (250 °F)
Recipe, share of the weight
- not statedIM7 carbon fibre
- not statedHexPly 8552 epoxy matrix
Best for
Primary aerospace structures that need high 0° strength and stiffness: 2724 MPa tensile strength and 164 GPa tensile modulus at 25 °C dry for the unidirectional prepreg (Hexcel datasheet)
Weakest at
Hot-wet performance: the measured longitudinal tensile strength falls from 371.08 ksi at room temperature dry to 327.96 ksi at 250 °F wet (NCAMP lamina test), and the datasheet service envelope is 121 °C (250 °F)
Risk at a glance
- People None found. No GHS hazard classification found in the sources read
- If it fails Moderate. Hot-wet strength loss
- Corrosion Moderate. Hot-wet conditioning lowers the measured longitudinal tensile strength from 371.08 ksi to 327.96 ksi.
Quick facts: IM7/8552
| Property | Value | Basis |
|---|---|---|
| Density | 1.3 to 1.77 g/cm³ | 3 sourced values across conditions |
| Tensile strength | 64 to 2,724 MPa | 6 sourced values across conditions |
| Young's modulus | 4.67 to 164 GPa | 4 sourced values across conditions |
| Maximum service temperature | 121 °C | 1 sourced value |
What is the density of Hexcel IM7/8552 carbon-epoxy prepreg?
Hexcel IM7/8552 carbon-epoxy prepreg has a density of 1.3 to 1.77 g/cm³. The range covers 3 sourced values across the tempers, forms and test conditions the sources report; room-temperature values are used where a source states a temperature.
What is the tensile strength of Hexcel IM7/8552 carbon-epoxy prepreg?
Hexcel IM7/8552 carbon-epoxy prepreg has a tensile strength of 64 to 2,724 MPa. The range covers 6 sourced values across the tempers, forms and test conditions the sources report; room-temperature values are used where a source states a temperature.
What is the Young's modulus of Hexcel IM7/8552 carbon-epoxy prepreg?
Hexcel IM7/8552 carbon-epoxy prepreg has a Young's modulus of 4.67 to 164 GPa. The range covers 4 sourced values across the tempers, forms and test conditions the sources report; room-temperature values are used where a source states a temperature.
What is the maximum service temperature of Hexcel IM7/8552 carbon-epoxy prepreg?
Hexcel IM7/8552 carbon-epoxy prepreg has a maximum service temperature of 121 °C. The source and test conditions are listed in the properties table on this page.
What is Hexcel IM7/8552 carbon-epoxy prepreg used for?
Uses recorded in the sources include Primary aerospace structures (unidirectional and woven prepreg); Honeycomb sandwich components; Space launcher and space and defence aircraft structures (typical uses).
Why it exists
HexPly 8552 IM7 is a carbon-epoxy prepreg for primary aerospace structures. It pairs IM7 carbon fibre with a toughened epoxy matrix and cures at 180 °C under pressure. The datasheet says the matrix gives good impact resistance and damage tolerance. An NCAMP qualification report prepared for an FAA special project records lamina test data for this material, so its strength and stiffness values come with a test record.
Where it's used
Primary aerospace structures
Hexcel describes HexPly 8552 as a high performance tough epoxy matrix for use in primary aerospace structures. The US edition also lists space launchers and space and defence aircraft structures among typical uses.
Honeycomb sandwich components
The datasheet gives a separate cure cycle for honeycomb sandwich components. It uses 3.2 bar gauge autoclave pressure, against 7 bar gauge for monolithic parts.
Recipe
Carbon fibre (IM7, 12K tow) reinforcement in an amine-cured, toughened epoxy matrix (HexPly 8552)
HexPly 8552 is an amine-cured, toughened epoxy matrix supplied with carbon fibre. The unidirectional IM7 prepreg uses IM7 carbon fibre in a 12K tow at a nominal fibre volume of 57.70 %, with the rest of the laminate volume taken by the resin. Carbon fibre is made from a precursor polymer such as polyacrylonitrile (PAN), spun into filaments and carbonized (Wikipedia). The composite is cured in an autoclave under vacuum and pressure, following the cure cycle in the properties.
| Ingredient | Share of the weight | What it does |
|---|---|---|
| IM7 carbon fibre | not stated | Carries most of the load along the fibre direction. The datasheet describes good translation of fibre properties into the laminate. |
| HexPly 8552 epoxy matrix | not stated | Amine-cured, toughened epoxy that binds the fibres, transfers load between them and sets the controlled flow and service envelope described in the datasheet. |
Weight shares are as printed in the sources.
What it can do
Stiffness
164 GPa
measured
The 0° tensile modulus of the unidirectional IM7 prepreg is 164 GPa at 25 °C dry, per the Hexcel EU datasheet. The AS4 version of the same resin prints 141 GPa.
Strength
2724 MPa
measured
The 0° tensile strength is 2724 MPa (395 ksi) at 25 °C dry, per the Hexcel EU datasheet.
Heat tolerance
200 °C dry, 154 °C wet
measured
The neat resin glass transition is 200 °C dry and 154 °C wet, per the Hexcel EU datasheet. The NCAMP laminate reads 406.43 °F dry and 321.41 °F wet by DMA, which is a different specimen and method.
Service environment
121 °C (250 °F)
measured
The datasheet says the system was developed to operate in environments up to 121 °C (250 °F).
How it compares
Against AS4 carbon fibre in the same HexPly 8552 matrix, IM7 gives a higher 0° tensile strength (2724 MPa against 2207 MPa at 25 °C dry) and a higher 0° tensile modulus (164 GPa against 141 GPa), per the same Hexcel EU datasheet table. The IM7 fibre is slightly less dense, at 1.77 g/cm3 against 1.79 g/cm3 for AS4. The short-beam shear strength is slightly higher for IM7 (137 MPa against 128 MPa dry at 25 °C). The table below compares the tensile strength, tensile modulus and density of IM7/8552 with the other properties in this record that a like-for-like comparison can use.
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.
| Measurement | IM7/8552 |
|---|---|
| Lifetime and stability | |
| Nominal fibre volume, unidirectional IM7 prepreg | 57.7 %4 |
| Fibre volume, NCAMP qualification material, method I | 58.53 %vol35 |
| Physical and electrical | |
| IM7 carbon fibre density | 1.77 g/cm³1 |
| Resin density, HexPly 8552 | 1.3 g/cm³2 |
| Nominal laminate density, unidirectional IM7/8552 | 1.57 g/cm³3 |
| Nominal cured ply thickness, 8552/35%/134 prepreg | 0.131 mm5 |
| Average cured ply thickness, NCAMP qualification material | 0.0072 inch36 |
| Temperature behavior | |
| Glass transition temperature, neat 8552 resin, dry | 200 °C6 |
| Glass transition temperature, neat 8552 resin, wet | 154 °C7 |
| Glass transition temperature, NCAMP qualification laminate, dry | 406.4 °F8 |
| Glass transition temperature, NCAMP qualification laminate, wet | 321.4 °F9 |
| Cure hold temperature, monolithic cure cycle | 180 °C26 |
| Cure first hold temperature, monolithic cure cycle | 110 °C27 |
| Other measurements | |
| Tensile strength, neat 8552 resin | 121 MPa10 |
| Tensile modulus, neat 8552 resin | 4670 MPa11 |
| 0° tensile strength at -55 °C, dry | 2572 MPa12 |
| 0° tensile strength at 25 °C, dry | 2724 MPa13 |
| 0° tensile modulus at -55 °C, dry | 163 GPa14 |
| 0° tensile modulus at 25 °C, dry | 164 GPa15 |
| 0° tensile elongation at 77 °F, dry | 1.62 %16 |
| Major Poisson's ratio in tension, dry | 0.316 -17 |
| 90° tensile strength at 25 °C, dry | 64 MPa18 |
| 90° tensile modulus at 25 °C, dry | 12 GPa19 |
| 0° compression strength at 25 °C, dry | 1690 MPa20 |
| 0° compression modulus at 25 °C, dry | 150 GPa21 |
| 0° short-beam (interlaminar) shear strength at 25 °C, dry | 137 MPa22 |
| 0° short-beam (interlaminar) shear strength at 25 °C, wet | 115 MPa23 |
| In-plane shear strength at 25 °C, dry | 120 MPa24 |
| Service environment the system was developed for | 121 °C25 |
| Autoclave pressure, monolithic components | 7 bar gauge28 |
| Autoclave pressure, honeycomb sandwich components | 3.2 bar gauge29 |
| Longitudinal tensile strength, NCAMP lamina, room temperature dry (measured) | 371.1 ksi30 |
| Longitudinal tensile modulus, NCAMP lamina, room temperature dry (measured) | 23.51 Msi31 |
| Longitudinal compression strength, NCAMP lamina, room temperature dry (measured) | 251.1 ksi32 |
| Longitudinal tensile strength, NCAMP lamina, hot-wet (measured) | 328 ksi33 |
| Transverse tensile strength, NCAMP lamina, room temperature dry (measured) | 9.29 ksi34 |
Why choose it, and why not
Good for
- Primary aerospace structures that need high 0° strength and stiffness. The unidirectional prepreg gives 2724 MPa and 164 GPa at 25 °C dry.
- Parts that need a test record. The NCAMP report gives lamina data with normalization to cured ply thickness.
Watch out for
- Hot-wet strength loss. Longitudinal tensile strength falls from 371.08 ksi at room temperature dry to 327.96 ksi at 250 °F wet.
- Service envelope of 121 °C (250 °F). The datasheet does not give a higher operating limit.
- Glass transition values differ by method. The neat resin reads 200 °C dry and 154 °C wet; the laminate reads 406.43 °F dry and 321.41 °F wet.
- Space exposure. No IM7/8552 atomic oxygen, UV or thermal-vacuum result was found; the one NASA abstract covers carbon fibre composites generally.
IM7/8552 is a well-documented aerospace prepreg: the datasheets and the NCAMP report give its 0° strength and stiffness and its hot-wet values. Its hot-wet strength and the 121 °C (250 °F) service envelope should be checked against the application.
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 | IM7 carbon fibre density | Value printed in the physical properties table of the unidirectional prepreg section | material IM7 carbon fibre as used in HexPly 8552 prepregprinted 1.77 (0.064) g/cm3 (lb/in3) | The AS4 fibre in the same table prints 1.79 g/cm3 (0.065 lb/in3). |
| 2 | Resin density, HexPly 8552 | Value printed in the physical properties table of the unidirectional prepreg section | material HexPly 8552 resin in the unidirectional prepregprinted 1.30 (0.047) g/cm3 (lb/in3) | The typical neat resin data on page 4 print 1.301 g/cc, which agrees. |
| 3 | Nominal laminate density, unidirectional IM7/8552 | Nominal value printed in the physical properties table | form cured unidirectional IM7/8552 laminate at nominal fibre volumeprinted 1.57 (0.057) g/cm3 (lb/in3) | — |
| 4 | Nominal fibre volume, unidirectional IM7 prepreg | Nominal value printed in the physical properties table | basis nominal value for the cured UD IM7/8552 prepreg (8552/35%/134) | — |
| 5 | Nominal cured ply thickness, 8552/35%/134 prepreg | Nominal value printed in the physical properties table | product IM7 unidirectional prepreg, 8552/35%/134printed 0.131 (0.0052) mm (inch) | — |
| 6 | Glass transition temperature, neat 8552 resin, dry | Printed as typical neat resin data; the EU edition does not name the method (the US edition names RDS 7700 and prints 392 °F dry) | material neat (unreinforced) HexPly 8552 resin, curedcondition dryprinted 200 °C (392 °F) | — |
| 7 | Glass transition temperature, neat 8552 resin, wet | Printed as typical neat resin data; the EU edition does not name the method (the US edition names RDS 7700 and prints 309 °F wet) | material neat (unreinforced) HexPly 8552 resin, curedcondition wetprinted 154 °C (309 °F) | — |
| 8 | Glass transition temperature, NCAMP qualification laminate, dry | Value printed in the lamina and laminate summary headers (DMA, SRM 18-94) | laminate IM7 unidirectional 190 gsm, 35% RC, cured to NPS 81228 M cure cyclecondition drystandard DMA per SACMA SRM 18-94 | Different specimen and method from the neat resin values above; the two sets are not interchangeable. |
| 9 | Glass transition temperature, NCAMP qualification laminate, wet | Value printed in the lamina and laminate summary headers (DMA, SRM 18-94) | laminate IM7 unidirectional 190 gsm, 35% RC, cured to NPS 81228 M cure cyclecondition wetstandard DMA per SACMA SRM 18-94 | Different specimen and method from the neat resin values above; the two sets are not interchangeable. |
| 10 | Tensile strength, neat 8552 resin | Printed as typical neat resin data; test temperature not printed | material neat HexPly 8552 resin, curedprinted 121 MPa (17.5 ksi) | — |
| 11 | Tensile modulus, neat 8552 resin | Printed as typical neat resin data; test temperature not printed | material neat HexPly 8552 resin, curedprinted 4670 MPa (0.677 msi) | — |
| 12 | 0° tensile strength at -55 °C, dry | Value printed in the UD mechanical properties table, IM7 column | fibre orientation 0°form unidirectional IM7/8552 prepreg, curedtemperature -55 °C (-67 °F)condition dryprinted 2572 (373) MPa (ksi) | — |
| 13 | 0° tensile strength at 25 °C, dry | Value printed in the UD mechanical properties table, IM7 column | fibre orientation 0°form unidirectional IM7/8552 prepreg, curedtemperature 25 °C (77 °F)condition dryprinted 2724 (395) MPa (ksi) | The AS4 fibre in the same row prints 2207 MPa (320 ksi). |
| 14 | 0° tensile modulus at -55 °C, dry | Value printed in the UD mechanical properties table, IM7 column | fibre orientation 0°form unidirectional IM7/8552 prepreg, curedtemperature -55 °C (-67 °F)condition dryprinted 163 (23.7) GPa (msi) | — |
| 15 | 0° tensile modulus at 25 °C, dry | Value printed in the UD mechanical properties table, IM7 column | fibre orientation 0°form unidirectional IM7/8552 prepreg, curedtemperature 25 °C (77 °F)condition dryprinted 164 (23.8) GPa (msi) | The AS4 fibre in the same row prints 141 GPa (20.5 msi). |
| 16 | 0° tensile elongation at 77 °F, dry | Value printed in the mechanical properties table of the US edition, IM7 column | fibre orientation 0°form unidirectional IM7/8552 prepregtemperature 77 °F (25 °C)condition dry | — |
| 17 | Major Poisson's ratio in tension, dry | Value printed in the mechanical properties table of the US edition, IM7 column | fibre orientation 0° (major Poisson's ratio, tension)temperature 77 °F (25 °C)condition dry | The NCAMP lamina test at room temperature dry also prints 0.316 for the longitudinal Poisson's ratio. |
| 18 | 90° tensile strength at 25 °C, dry | Value printed in the UD mechanical properties table, IM7 column | fibre orientation 90°form unidirectional IM7/8552 prepreg, curedtemperature 25 °C (77 °F)condition dryprinted 64 (9.3) MPa (ksi) | The AS4 fibre in the same row prints 81 MPa (11.7 ksi). |
| 19 | 90° tensile modulus at 25 °C, dry | Value printed in the UD mechanical properties table, IM7 column | fibre orientation 90°form unidirectional IM7/8552 prepreg, curedtemperature 25 °C (77 °F)condition dryprinted 12 (1.7) GPa (msi) | The AS4 fibre in the same row prints 10 GPa (1.39 msi). |
| 20 | 0° compression strength at 25 °C, dry | Value printed in the UD mechanical properties table, IM7 column | fibre orientation 0°form unidirectional IM7/8552 prepreg, curedtemperature 25 °C (77 °F)condition dryprinted 1690 (245) MPa (ksi) | Not a canonical property name; the AS4 fibre in the same row prints 1531 MPa (222 ksi). |
| 21 | 0° compression modulus at 25 °C, dry | Value printed in the UD mechanical properties table, IM7 column | fibre orientation 0°form unidirectional IM7/8552 prepreg, curedtemperature 25 °C (77 °F)condition dryprinted 150 (21.7) GPa (msi) | Not a canonical property name; the AS4 fibre in the same row prints 128 GPa (18.6 msi). |
| 22 | 0° short-beam (interlaminar) shear strength at 25 °C, dry | Value printed in the UD mechanical properties table, IM7 column | fibre orientation 0°test short-beam sheartemperature 25 °C (77 °F)condition dryprinted 137 (19.9) MPa (ksi) | Not a canonical property name; the AS4 fibre in the same row prints 128 MPa (18.5 ksi). |
| 23 | 0° short-beam (interlaminar) shear strength at 25 °C, wet | Value printed in the UD mechanical properties table, IM7 column; the datasheet labels this row as wet | fibre orientation 0°test short-beam sheartemperature 25 °C (77 °F)condition wetprinted 115 (16.7) MPa (ksi) | Dry value at the same temperature is 137 MPa (19.9 ksi). |
| 24 | In-plane shear strength at 25 °C, dry | Value printed in the UD mechanical properties table, IM7 column | temperature 25 °C (77 °F)condition dryprinted 120 (17.4) MPa (ksi) | Not a canonical property name; the AS4 fibre in the same row prints 114 MPa (16.6 ksi). |
| 25 | Service environment the system was developed for | Value printed in the product description; a development statement, not a qualification limit | basis environments the system was developed to operate inprinted 121 °C (250 °F) | — |
| 26 | Cure hold temperature, monolithic cure cycle | Cure cycle printed in the curing conditions section (steps 6 to 8) | tolerance ±5 °Chold 120 minutes ±5 minutespressure 7 bar gauge autoclave pressure for monolithic componentsheating 1 to 3 °C/min to hold temperaturecooling 2 to 5 °C/min | — |
| 27 | Cure first hold temperature, monolithic cure cycle | Cure cycle printed in the curing conditions section (steps 4 and 5) | tolerance ±5 °Chold 60 minutes ±5 minutesheating 1 to 3 °C/min to first holdvacuum full vacuum (1 bar) applied at the start | — |
| 28 | Autoclave pressure, monolithic components | Cure cycle printed in the curing conditions section (step 2) | part monolithic componentsvacuum reduction vacuum reduced to a safety value of 0.2 bar when autoclave pressure reaches approximately 1 bar gauge | — |
| 29 | Autoclave pressure, honeycomb sandwich components | Cure cycle printed in the curing conditions section (step 2 of the honeycomb cycle) | part honeycomb sandwich componentsvacuum reduction vacuum reduced to a safety value of 0.2 bar when autoclave pressure reaches approximately 1 bar gauge | — |
| 30 | Longitudinal tensile strength, NCAMP lamina, room temperature dry (measured) | Measured column of the lamina mechanical property summary, normalized values also reported | test condition RTD: 70 ±10 °F, room temperature dryfibre IM7 unidirectionalresin Hexcel 8552cure NPS 81228 M cure cyclelot basis mean of lots 1 to 3 | Normalized to cured ply thickness 0.0072 inch, the same mean is 362.69 ksi. |
| 31 | Longitudinal tensile modulus, NCAMP lamina, room temperature dry (measured) | Measured column of the lamina mechanical property summary, normalized values also reported | test condition RTD: 70 ±10 °F, room temperature dryfibre IM7 unidirectionalresin Hexcel 8552cure NPS 81228 M cure cycle | Normalized to cured ply thickness 0.0072 inch, the same mean is 22.99 Msi. |
| 32 | Longitudinal compression strength, NCAMP lamina, room temperature dry (measured) | Measured column of the lamina mechanical property summary, normalized values also reported | test condition RTD: 70 ±10 °F, room temperature dryfibre IM7 unidirectionalcure NPS 81228 M cure cycletest unnotched compression 0 (UNC0) | Not a canonical property name; normalized to cured ply thickness 0.0072 inch, the same mean is 248.94 ksi. |
| 33 | Longitudinal tensile strength, NCAMP lamina, hot-wet (measured) | Measured column of the lamina mechanical property summary, normalized values also reported | test condition ETW: 250 ±5 °F, wet (equilibrium moisture content)fibre IM7 unidirectionalcure NPS 81228 M cure cycle | Normalized to cured ply thickness 0.0072 inch, the same mean is 333.50 ksi. |
| 34 | Transverse tensile strength, NCAMP lamina, room temperature dry (measured) | Measured column of the lamina mechanical property summary; transverse values are not normalized in the report | test condition RTD: 70 ±10 °F, room temperature dryfibre IM7 unidirectionaldirection transverse (from TT) | Not a canonical property name for direction; the EU datasheet prints 64 MPa (9.3 ksi) at 25 °C dry for the 90° tensile strength. |
| 35 | Fibre volume, NCAMP qualification material, method I | Value printed in the normalization procedures section | method ASTM D3171 Method I (acid digestion)product IM7 unidirectional prepreg, 190 gsm and 35% RC | Method II gives 59.405 %vol; the report calls the two close enough. |
| 36 | Average cured ply thickness, NCAMP qualification material | Value printed in the normalization procedures section | product IM7 unidirectional prepreg, 190 gsm and 35% RCbasis average used as nominal for normalization | The datasheet 8552/35%/134 product prints 0.131 mm (0.0052 inch); the two products differ in areal weight. |
Corrosion and compatibility
What happens when it meets other materials and environments.
| Environment | Concern | What happens |
|---|---|---|
| Hot and wet: 250 °F wet to equilibrium moisture content (NCAMP lamina test) | moderate | Hot-wet conditioning lowers the measured longitudinal tensile strength from 371.08 ksi to 327.96 ksi.1 |
| Wet conditioning of the neat resin (datasheet) | moderate | The neat resin glass transition falls from 200 °C dry to 154 °C wet.2 |
| Wet conditioning of the qualification laminate, DMA | moderate | The laminate glass transition falls from 406.43 °F dry to 321.41 °F wet.3 |
| Wet short-beam shear at 25 °C | low | Wet short-beam shear at 25 °C is 115 MPa, against 137 MPa dry.4 |
| Atomic oxygen and erosion in low Earth orbit, carbon fibre composites (general) | not rated | A NASA LDEF abstract reports about one ply of carbon fibre composite eroded in 70 months in low Earth orbit.5 |
| # | Environment | Details | Test conditions |
|---|---|---|---|
| 1 | Hot and wet: 250 °F wet to equilibrium moisture content (NCAMP lamina test) | The qualification test reads the same lamina at room temperature dry and at 250 °F wet. Both are measured values; the normalized means are 362.69 ksi and 333.50 ksi. | dry RTD: 70 ±10 °F, room temperature drywet ETW: 250 ±5 °F, wet (equilibrium moisture content) |
| 2 | Wet conditioning of the neat resin (datasheet) | Typical neat resin data from the EU datasheet. The US edition prints 392 °F dry and 309 °F wet under RDS 7700, so the two editions agree on the same resin. | basis typical neat resin data; method not named in the EU edition |
| 3 | Wet conditioning of the qualification laminate, DMA | Measured by DMA under SACMA SRM 18-94 on the NCAMP qualification laminate. The neat resin values above come from a different specimen and are not interchangeable with these. | standard DMA per SACMA SRM 18-94laminate IM7 unidirectional 190 gsm, 35% RC |
| 4 | Wet short-beam shear at 25 °C | Both values are printed in the IM7 column at 25 °C, for the dry and wet condition rows of the datasheet's mechanical table. | temperature 25 °C (77 °F)test 0° short-beam shear |
| 5 | Atomic oxygen and erosion in low Earth orbit, carbon fibre composites (general) | The abstract covers carbon fibre composites generally, not IM7/8552, and gives no erosion yield. It says matrix erosion was more evident for a polysulfone matrix than for epoxy matrices. | exposure 70 months, LDEF SAMPLE experimentmaterial carbon fibre composites (general; resin not named for the eroded ply) |
Risks and side effects
Hazards to people, what happens when a cell overheats, and how the material is handled and stored.
For people
The Hexcel datasheet points to a separate safety data sheet for this product, which was not retrieved. Hazard information here is limited to the datasheet precautions.
- Uncured prepreg
- The datasheet says the usual precautions for uncured synthetic resins and fine fibrous materials apply, and recommends clean disposable inert gloves.
- Cured composite
- The sources read give no toxicology or dust data for the cured composite. That gap is listed under gaps.
Hot and wet
Moisture and heat lower the glass transition and the strength measured in the qualification tests.
- Strength
- Longitudinal tensile strength fell from 371.08 ksi at room temperature dry to 327.96 ksi at 250 °F wet, measured in NCAMP lamina tests.
- Short-beam shear
- The datasheet prints 137 MPa dry and 115 MPa wet at 25 °C.
- Glass transition
- The laminate glass transition is 406.43 °F dry and 321.41 °F wet by DMA. The neat resin is 200 °C dry and 154 °C wet in the datasheet. The two sets use different specimens and are not directly comparable.
Handling and storage
- Freezer storage
- The prepreg is stored frozen at -18 °C, with a maximum shelf life of 12 months from manufacture, in a sealed moisture-proof bag.
- Working time
- Tack life is 10 days at 23 °C. Out life, the time between removal from the freezer and cure, is 30 days at 23 °C.
Test details
The original wording and numbers from the sources, for readers who want them.
Failure risks
| Failure | Trigger and consequence |
|---|---|
| Hot-wet strength lossmoderate severity | Conditioning at 250 °F wet to equilibrium moisture contentLongitudinal tensile strength measured 327.96 ksi, against 371.08 ksi at room temperature dry (NCAMP lamina test). |
| Use above the datasheet service envelopemoderate severity | Operation above 121 °C (250 °F)The datasheet says the system was developed for environments up to 121 °C (250 °F). It gives no performance statement above that temperature. |
Handling and storage
- Store the prepreg frozen at -18 °C in a sealed moisture-proof bag. Shelf life is 12 months at -18 °C from date of manufacture (maximum).
- Tack life is 10 days at 23 °C (73 °F). Out life, the time between removal from the freezer and cure, is 30 days at 23 °C.
- Use clean disposable inert gloves to protect the operator and avoid contaminating the material and components.
Mitigations
- Performance testing should accompany alternative cure cycles to ensure suitability for the particular application.
Supply and geography
How common the raw materials are and where they come from.
Carbon fibre precursor (polyacrylonitrile, PAN)
Acrylonitrile (PAN monomer)
Carbon fibre (Hexcel PAN-based fibre)
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: im7-8552
spore_version: 0.2
family: carbon-epoxy
name: Hexcel IM7/8552 carbon-epoxy prepreg
abbreviation: IM7/8552
role: unidirectional and woven aerospace structural prepreg
category: composites
type: carbon-fiber-reinforced
summary: |
IM7/8552 is a carbon-epoxy prepreg made from Hexcel IM7 carbon fibre and HexPly 8552, an amine-cured, toughened epoxy matrix. For the unidirectional prepreg, the Hexcel European datasheet gives a 0° tensile strength of 2724 MPa and a 0° tensile modulus of 164 GPa at 25 °C dry. The NCAMP qualification report gives a laminate glass transition of 406.43 °F dry and 321.41 °F wet by DMA, while the neat resin datasheet gives 200 °C dry and 154 °C wet; the two methods are not directly comparable.
best_for: 'Primary aerospace structures that need high 0° strength and stiffness: 2724 MPa tensile strength and 164 GPa tensile modulus at 25 °C dry for the unidirectional prepreg (Hexcel datasheet)'
weakest_at: 'Hot-wet performance: the measured longitudinal tensile strength falls from 371.08 ksi at room temperature dry to 327.96 ksi at 250 °F wet (NCAMP lamina test), and the datasheet service envelope is 121 °C (250 °F)'
identity:
formula: Carbon fibre (IM7, 12K tow) reinforcement in an amine-cured, toughened epoxy matrix (HexPly 8552)
source: hexcel-eu-ds
where: 'Page 1 (description: amine cured, toughened epoxy supplied with unidirectional or woven carbon fibres); page 2 (IM7 filament count 12K)'
designations: []
tags:
applications:
- structures
properties:
- benchmark: density
label: IM7 carbon fibre density
value: 1.77
unit: g/cm3
scope: material
conditions:
material: IM7 carbon fibre as used in HexPly 8552 prepreg
printed: 1.77 (0.064) g/cm3 (lb/in3)
method: Value printed in the physical properties table of the unidirectional prepreg section
status: ground
note: The AS4 fibre in the same table prints 1.79 g/cm3 (0.065 lb/in3).
source: hexcel-eu-ds
where: Page 2, Prepreg Properties (UD carbon prepregs), Physical Properties, Fibre Density row, IM7 column
- benchmark: density
label: Resin density, HexPly 8552
value: 1.3
unit: g/cm3
scope: material
conditions:
material: HexPly 8552 resin in the unidirectional prepreg
printed: 1.30 (0.047) g/cm3 (lb/in3)
method: Value printed in the physical properties table of the unidirectional prepreg section
status: ground
note: The typical neat resin data on page 4 print 1.301 g/cc, which agrees.
source: hexcel-eu-ds
where: Page 2, Prepreg Properties (UD carbon prepregs), Physical Properties, Resin density row
- benchmark: density
label: Nominal laminate density, unidirectional IM7/8552
value: 1.57
unit: g/cm3
scope: material
conditions:
form: cured unidirectional IM7/8552 laminate at nominal fibre volume
printed: 1.57 (0.057) g/cm3 (lb/in3)
method: Nominal value printed in the physical properties table
status: ground
source: hexcel-eu-ds
where: Page 2, Prepreg Properties (UD carbon prepregs), Nominal Laminate Density row, IM7 column
- benchmark: fibre_volume_fraction
label: Nominal fibre volume, unidirectional IM7 prepreg
value: 57.7
unit: '%'
scope: material
conditions:
basis: nominal value for the cured UD IM7/8552 prepreg (8552/35%/134)
method: Nominal value printed in the physical properties table
status: ground
source: hexcel-eu-ds
where: Page 2, Prepreg Properties (UD carbon prepregs), Nominal Fibre Volume row, IM7 column
- benchmark: cured_ply_thickness
label: Nominal cured ply thickness, 8552/35%/134 prepreg
value: 0.131
unit: mm
scope: material
conditions:
product: IM7 unidirectional prepreg, 8552/35%/134
printed: 0.131 (0.0052) mm (inch)
method: Nominal value printed in the physical properties table
status: ground
source: hexcel-eu-ds
where: Page 2, Prepreg Properties (UD carbon prepregs), Nominal Cured Ply Thickness row, IM7 column
- benchmark: glass_transition_temperature
label: Glass transition temperature, neat 8552 resin, dry
value: 200
unit: °C
scope: material
conditions:
material: neat (unreinforced) HexPly 8552 resin, cured
condition: dry
printed: 200 °C (392 °F)
method: Printed as typical neat resin data; the EU edition does not name the method (the US edition names RDS 7700 and prints 392 °F dry)
status: ground
source: hexcel-eu-ds
where: Page 4, Typical Neat Resin Data, Tg dry
- benchmark: glass_transition_temperature
label: Glass transition temperature, neat 8552 resin, wet
value: 154
unit: °C
scope: material
conditions:
material: neat (unreinforced) HexPly 8552 resin, cured
condition: wet
printed: 154 °C (309 °F)
method: Printed as typical neat resin data; the EU edition does not name the method (the US edition names RDS 7700 and prints 309 °F wet)
status: ground
source: hexcel-eu-ds
where: Page 4, Typical Neat Resin Data, Tg wet
- benchmark: glass_transition_temperature
label: Glass transition temperature, NCAMP qualification laminate, dry
value: 406.43
unit: °F
scope: material
conditions:
laminate: IM7 unidirectional 190 gsm, 35% RC, cured to NPS 81228 M cure cycle
condition: dry
standard: DMA per SACMA SRM 18-94
method: Value printed in the lamina and laminate summary headers (DMA, SRM 18-94)
status: ground
note: Different specimen and method from the neat resin values above; the two sets are not interchangeable.
source: ornl-ncamp-2011
where: Section 2.1 (Lamina Level Test Summary), header, Tg(dry); the same value is repeated in Section 2.2
- benchmark: glass_transition_temperature
label: Glass transition temperature, NCAMP qualification laminate, wet
value: 321.41
unit: °F
scope: material
conditions:
laminate: IM7 unidirectional 190 gsm, 35% RC, cured to NPS 81228 M cure cycle
condition: wet
standard: DMA per SACMA SRM 18-94
method: Value printed in the lamina and laminate summary headers (DMA, SRM 18-94)
status: ground
note: Different specimen and method from the neat resin values above; the two sets are not interchangeable.
source: ornl-ncamp-2011
where: Section 2.1 (Lamina Level Test Summary), header, Tg(wet); the same value is repeated in Section 2.2
- benchmark: ultimate_tensile_strength
label: Tensile strength, neat 8552 resin
value: 121
unit: MPa
scope: material
conditions:
material: neat HexPly 8552 resin, cured
printed: 121 MPa (17.5 ksi)
method: Printed as typical neat resin data; test temperature not printed
status: ground
source: hexcel-eu-ds
where: Page 4, Typical Neat Resin Data, Tensile Strength
- benchmark: elastic_modulus
label: Tensile modulus, neat 8552 resin
value: 4670
unit: MPa
scope: material
conditions:
material: neat HexPly 8552 resin, cured
printed: 4670 MPa (0.677 msi)
method: Printed as typical neat resin data; test temperature not printed
status: ground
source: hexcel-eu-ds
where: Page 4, Typical Neat Resin Data, Tensile Modulus
- benchmark: ultimate_tensile_strength
label: 0° tensile strength at -55 °C, dry
value: 2572
unit: MPa
scope: material
conditions:
fibre_orientation: 0°
form: unidirectional IM7/8552 prepreg, cured
temperature: '-55 °C (-67 °F)'
condition: dry
printed: 2572 (373) MPa (ksi)
method: Value printed in the UD mechanical properties table, IM7 column
status: ground
source: hexcel-eu-ds
where: Page 2, Mechanical Properties, 0° Tensile Strength, -55 (-67) Dry, IM7 column
- benchmark: ultimate_tensile_strength
label: 0° tensile strength at 25 °C, dry
value: 2724
unit: MPa
scope: material
conditions:
fibre_orientation: 0°
form: unidirectional IM7/8552 prepreg, cured
temperature: 25 °C (77 °F)
condition: dry
printed: 2724 (395) MPa (ksi)
method: Value printed in the UD mechanical properties table, IM7 column
status: ground
note: The AS4 fibre in the same row prints 2207 MPa (320 ksi).
source: hexcel-eu-ds
where: Page 2, Mechanical Properties, 0° Tensile Strength, 25 (77) Dry, IM7 column
- benchmark: elastic_modulus
label: 0° tensile modulus at -55 °C, dry
value: 163
unit: GPa
scope: material
conditions:
fibre_orientation: 0°
form: unidirectional IM7/8552 prepreg, cured
temperature: '-55 °C (-67 °F)'
condition: dry
printed: 163 (23.7) GPa (msi)
method: Value printed in the UD mechanical properties table, IM7 column
status: ground
source: hexcel-eu-ds
where: Page 2, Mechanical Properties, 0° Tensile Modulus, -55 (-67) Dry, IM7 column
- benchmark: elastic_modulus
label: 0° tensile modulus at 25 °C, dry
value: 164
unit: GPa
scope: material
conditions:
fibre_orientation: 0°
form: unidirectional IM7/8552 prepreg, cured
temperature: 25 °C (77 °F)
condition: dry
printed: 164 (23.8) GPa (msi)
method: Value printed in the UD mechanical properties table, IM7 column
status: ground
note: The AS4 fibre in the same row prints 141 GPa (20.5 msi).
source: hexcel-eu-ds
where: Page 2, Mechanical Properties, 0° Tensile Modulus, 25 (77) Dry, IM7 column
- benchmark: elongation
label: 0° tensile elongation at 77 °F, dry
value: 1.62
unit: '%'
scope: material
conditions:
fibre_orientation: 0°
form: unidirectional IM7/8552 prepreg
temperature: 77 °F (25 °C)
condition: dry
method: Value printed in the mechanical properties table of the US edition, IM7 column
status: ground
source: hexcel-us-ds
where: Page 3, Mechanical Properties, 0° Tensile elongation, %, 77 Dry, IM7 column
- benchmark: poissons_ratio
label: Major Poisson's ratio in tension, dry
value: 0.316
unit: '-'
scope: material
conditions:
fibre_orientation: 0° (major Poisson's ratio, tension)
temperature: 77 °F (25 °C)
condition: dry
method: Value printed in the mechanical properties table of the US edition, IM7 column
status: ground
note: The NCAMP lamina test at room temperature dry also prints 0.316 for the longitudinal Poisson's ratio.
source: hexcel-us-ds
where: Page 3, Mechanical Properties, Major Poisson's Ratio, tension, 77 Dry, IM7 column
- benchmark: ultimate_tensile_strength
label: 90° tensile strength at 25 °C, dry
value: 64
unit: MPa
scope: material
conditions:
fibre_orientation: 90°
form: unidirectional IM7/8552 prepreg, cured
temperature: 25 °C (77 °F)
condition: dry
printed: 64 (9.3) MPa (ksi)
method: Value printed in the UD mechanical properties table, IM7 column
status: ground
note: The AS4 fibre in the same row prints 81 MPa (11.7 ksi).
source: hexcel-eu-ds
where: Page 2, Mechanical Properties, 90° Tensile Strength, 25 (77) Dry, IM7 column
- benchmark: elastic_modulus
label: 90° tensile modulus at 25 °C, dry
value: 12
unit: GPa
scope: material
conditions:
fibre_orientation: 90°
form: unidirectional IM7/8552 prepreg, cured
temperature: 25 °C (77 °F)
condition: dry
printed: 12 (1.7) GPa (msi)
method: Value printed in the UD mechanical properties table, IM7 column
status: ground
note: The AS4 fibre in the same row prints 10 GPa (1.39 msi).
source: hexcel-eu-ds
where: Page 2, Mechanical Properties, 90° Tensile Modulus, 25 (77) Dry, IM7 column
- benchmark: compressive_strength_0deg
label: 0° compression strength at 25 °C, dry
value: 1690
unit: MPa
scope: material
conditions:
fibre_orientation: 0°
form: unidirectional IM7/8552 prepreg, cured
temperature: 25 °C (77 °F)
condition: dry
printed: 1690 (245) MPa (ksi)
method: Value printed in the UD mechanical properties table, IM7 column
status: ground
note: Not a canonical property name; the AS4 fibre in the same row prints 1531 MPa (222 ksi).
source: hexcel-eu-ds
where: Page 2, Mechanical Properties, 0° Compression Strength, 25 (77) Dry, IM7 column
- benchmark: compressive_modulus_0deg
label: 0° compression modulus at 25 °C, dry
value: 150
unit: GPa
scope: material
conditions:
fibre_orientation: 0°
form: unidirectional IM7/8552 prepreg, cured
temperature: 25 °C (77 °F)
condition: dry
printed: 150 (21.7) GPa (msi)
method: Value printed in the UD mechanical properties table, IM7 column
status: ground
note: Not a canonical property name; the AS4 fibre in the same row prints 128 GPa (18.6 msi).
source: hexcel-eu-ds
where: Page 2, Mechanical Properties, 0° Compression Modulus, 25 (77) Dry, IM7 column
- benchmark: interlaminar_shear_strength_short_beam
label: 0° short-beam (interlaminar) shear strength at 25 °C, dry
value: 137
unit: MPa
scope: material
conditions:
fibre_orientation: 0°
test: short-beam shear
temperature: 25 °C (77 °F)
condition: dry
printed: 137 (19.9) MPa (ksi)
method: Value printed in the UD mechanical properties table, IM7 column
status: ground
note: Not a canonical property name; the AS4 fibre in the same row prints 128 MPa (18.5 ksi).
source: hexcel-eu-ds
where: Page 2, Mechanical Properties, 0° ILSS (Shortbeam shear), 25 (77) Dry, IM7 column
- benchmark: interlaminar_shear_strength_short_beam
label: 0° short-beam (interlaminar) shear strength at 25 °C, wet
value: 115
unit: MPa
scope: material
conditions:
fibre_orientation: 0°
test: short-beam shear
temperature: 25 °C (77 °F)
condition: wet
printed: 115 (16.7) MPa (ksi)
method: Value printed in the UD mechanical properties table, IM7 column; the datasheet labels this row as wet
status: ground
note: Dry value at the same temperature is 137 MPa (19.9 ksi).
source: hexcel-eu-ds
where: Page 2, Mechanical Properties, 0° ILSS (Shortbeam shear), 25 (77) Wet, IM7 column
- benchmark: in_plane_shear_strength
label: In-plane shear strength at 25 °C, dry
value: 120
unit: MPa
scope: material
conditions:
temperature: 25 °C (77 °F)
condition: dry
printed: 120 (17.4) MPa (ksi)
method: Value printed in the UD mechanical properties table, IM7 column
status: ground
note: Not a canonical property name; the AS4 fibre in the same row prints 114 MPa (16.6 ksi).
source: hexcel-eu-ds
where: Page 2, Mechanical Properties, In-plane Shear Strength, 25 (77) Dry, IM7 column
- benchmark: max_service_temp
label: Service environment the system was developed for
value: 121
unit: °C
scope: material
conditions:
basis: environments the system was developed to operate in
printed: 121 °C (250 °F)
method: Value printed in the product description; a development statement, not a qualification limit
status: ground
source: hexcel-eu-ds
where: Page 1, Description
- benchmark: cure_hold_temperature
label: Cure hold temperature, monolithic cure cycle
value: 180
unit: °C
scope: material
conditions:
tolerance: ±5 °C
hold: 120 minutes ±5 minutes
pressure: 7 bar gauge autoclave pressure for monolithic components
heating: 1 to 3 °C/min to hold temperature
cooling: 2 to 5 °C/min
method: Cure cycle printed in the curing conditions section (steps 6 to 8)
status: ground
source: hexcel-eu-ds
where: Page 5, Curing Conditions, monolithic cure cycle, steps 6 to 8
- benchmark: cure_stage1_temperature
label: Cure first hold temperature, monolithic cure cycle
value: 110
unit: °C
scope: material
conditions:
tolerance: ±5 °C
hold: 60 minutes ±5 minutes
heating: 1 to 3 °C/min to first hold
vacuum: full vacuum (1 bar) applied at the start
method: Cure cycle printed in the curing conditions section (steps 4 and 5)
status: ground
source: hexcel-eu-ds
where: Page 5, Curing Conditions, monolithic cure cycle, steps 4 and 5
- benchmark: cure_pressure
label: Autoclave pressure, monolithic components
value: 7
unit: bar gauge
scope: material
conditions:
part: monolithic components
vacuum_reduction: vacuum reduced to a safety value of 0.2 bar when autoclave pressure reaches approximately 1 bar gauge
method: Cure cycle printed in the curing conditions section (step 2)
status: ground
source: hexcel-eu-ds
where: Page 5, Curing Conditions, monolithic cure cycle, step 2
- benchmark: cure_pressure
label: Autoclave pressure, honeycomb sandwich components
value: 3.2
unit: bar gauge
scope: material
conditions:
part: honeycomb sandwich components
vacuum_reduction: vacuum reduced to a safety value of 0.2 bar when autoclave pressure reaches approximately 1 bar gauge
method: Cure cycle printed in the curing conditions section (step 2 of the honeycomb cycle)
status: ground
source: hexcel-eu-ds
where: Page 5, Curing Conditions, honeycomb sandwich cure cycle, step 2
- benchmark: ultimate_tensile_strength
label: Longitudinal tensile strength, NCAMP lamina, room temperature dry (measured)
value: 371.08
unit: ksi
scope: material
conditions:
test_condition: 'RTD: 70 ±10 °F, room temperature dry'
fibre: IM7 unidirectional
resin: Hexcel 8552
cure: NPS 81228 M cure cycle
lot_basis: mean of lots 1 to 3
method: Measured column of the lamina mechanical property summary, normalized values also reported
status: ground
note: Normalized to cured ply thickness 0.0072 inch, the same mean is 362.69 ksi.
source: ornl-ncamp-2011
where: Section 2.1 (Lamina Level Test Summary), Table 2-1, from LT row, RTD measured column
- benchmark: elastic_modulus
label: Longitudinal tensile modulus, NCAMP lamina, room temperature dry (measured)
value: 23.51
unit: Msi
scope: material
conditions:
test_condition: 'RTD: 70 ±10 °F, room temperature dry'
fibre: IM7 unidirectional
resin: Hexcel 8552
cure: NPS 81228 M cure cycle
method: Measured column of the lamina mechanical property summary, normalized values also reported
status: ground
note: Normalized to cured ply thickness 0.0072 inch, the same mean is 22.99 Msi.
source: ornl-ncamp-2011
where: Section 2.1 (Lamina Level Test Summary), Table 2-1, E1 of LT row, RTD measured column
- benchmark: compressive_strength_0deg
label: Longitudinal compression strength, NCAMP lamina, room temperature dry (measured)
value: 251.13
unit: ksi
scope: material
conditions:
test_condition: 'RTD: 70 ±10 °F, room temperature dry'
fibre: IM7 unidirectional
cure: NPS 81228 M cure cycle
test: unnotched compression 0 (UNC0)
method: Measured column of the lamina mechanical property summary, normalized values also reported
status: ground
note: Not a canonical property name; normalized to cured ply thickness 0.0072 inch, the same mean is 248.94 ksi.
source: ornl-ncamp-2011
where: Section 2.1 (Lamina Level Test Summary), Table 2-1, F1cu from UNC0 row, RTD measured column
- benchmark: ultimate_tensile_strength
label: Longitudinal tensile strength, NCAMP lamina, hot-wet (measured)
value: 327.96
unit: ksi
scope: material
conditions:
test_condition: 'ETW: 250 ±5 °F, wet (equilibrium moisture content)'
fibre: IM7 unidirectional
cure: NPS 81228 M cure cycle
method: Measured column of the lamina mechanical property summary, normalized values also reported
status: ground
note: Normalized to cured ply thickness 0.0072 inch, the same mean is 333.50 ksi.
source: ornl-ncamp-2011
where: Section 2.1 (Lamina Level Test Summary), Table 2-1, from LT row, ETW measured column
- benchmark: ultimate_tensile_strength
label: Transverse tensile strength, NCAMP lamina, room temperature dry (measured)
value: 9.29
unit: ksi
scope: material
conditions:
test_condition: 'RTD: 70 ±10 °F, room temperature dry'
fibre: IM7 unidirectional
direction: transverse (from TT)
method: Measured column of the lamina mechanical property summary; transverse values are not normalized in the report
status: ground
note: Not a canonical property name for direction; the EU datasheet prints 64 MPa (9.3 ksi) at 25 °C dry for the 90° tensile strength.
source: ornl-ncamp-2011
where: Section 2.1 (Lamina Level Test Summary), Table 2-1, F2 tu (from TT) row, RTD measured column
- benchmark: fibre_volume_fraction
label: Fibre volume, NCAMP qualification material, method I
value: 58.535
unit: '%vol'
scope: material
conditions:
method: ASTM D3171 Method I (acid digestion)
product: IM7 unidirectional prepreg, 190 gsm and 35% RC
method: Value printed in the normalization procedures section
status: ground
note: Method II gives 59.405 %vol; the report calls the two close enough.
source: ornl-ncamp-2011
where: Section 1.5.8 (Normalization Procedures), fiber volume paragraph
- benchmark: cured_ply_thickness
label: Average cured ply thickness, NCAMP qualification material
value: 0.0072
unit: inch
scope: material
conditions:
product: IM7 unidirectional prepreg, 190 gsm and 35% RC
basis: average used as nominal for normalization
method: Value printed in the normalization procedures section
status: ground
note: The datasheet 8552/35%/134 product prints 0.131 mm (0.0052 inch); the two products differ in areal weight.
source: ornl-ncamp-2011
where: Section 1.5.8 (Normalization Procedures), fiber volume paragraph
corrosion:
- environment: 'Hot and wet: 250 °F wet to equilibrium moisture content (NCAMP lamina test)'
headline: Hot-wet conditioning lowers the measured longitudinal tensile strength from 371.08 ksi to 327.96 ksi.
effect: The qualification test reads the same lamina at room temperature dry and at 250 °F wet. Both are measured values; the normalized means are 362.69 ksi and 333.50 ksi.
rating: moderate
conditions:
dry: 'RTD: 70 ±10 °F, room temperature dry'
wet: 'ETW: 250 ±5 °F, wet (equilibrium moisture content)'
source: ornl-ncamp-2011
where: Section 2.1 (Lamina Level Test Summary), Table 2-1, from LT row
- environment: Wet conditioning of the neat resin (datasheet)
headline: The neat resin glass transition falls from 200 °C dry to 154 °C wet.
effect: Typical neat resin data from the EU datasheet. The US edition prints 392 °F dry and 309 °F wet under RDS 7700, so the two editions agree on the same resin.
rating: moderate
conditions:
basis: typical neat resin data; method not named in the EU edition
source: hexcel-eu-ds
where: Page 4, Typical Neat Resin Data, Tg dry and Tg wet
- environment: Wet conditioning of the qualification laminate, DMA
headline: The laminate glass transition falls from 406.43 °F dry to 321.41 °F wet.
effect: Measured by DMA under SACMA SRM 18-94 on the NCAMP qualification laminate. The neat resin values above come from a different specimen and are not interchangeable with these.
rating: moderate
conditions:
standard: DMA per SACMA SRM 18-94
laminate: IM7 unidirectional 190 gsm, 35% RC
source: ornl-ncamp-2011
where: Section 2.1 (Lamina Level Test Summary), header, Tg(dry) and Tg(wet)
- environment: Wet short-beam shear at 25 °C
headline: Wet short-beam shear at 25 °C is 115 MPa, against 137 MPa dry.
effect: Both values are printed in the IM7 column at 25 °C, for the dry and wet condition rows of the datasheet's mechanical table.
rating: low
conditions:
temperature: 25 °C (77 °F)
test: 0° short-beam shear
source: hexcel-eu-ds
where: Page 2, Mechanical Properties, 0° ILSS (Shortbeam shear), 25 (77) Dry and Wet, IM7 column
- environment: Atomic oxygen and erosion in low Earth orbit, carbon fibre composites (general)
headline: A NASA LDEF abstract reports about one ply of carbon fibre composite eroded in 70 months in low Earth orbit.
effect: The abstract covers carbon fibre composites generally, not IM7/8552, and gives no erosion yield. It says matrix erosion was more evident for a polysulfone matrix than for epoxy matrices.
rating: unknown
conditions:
exposure: 70 months, LDEF SAMPLE experiment
material: carbon fibre composites (general; resin not named for the eroded ply)
source: nasa-ldes-ntrs
where: Abstract
risks:
hazards:
- text: The datasheet says the usual precautions for uncured synthetic resins and fine fibrous materials should be observed, and that a safety data sheet is available. The SDS was not retrieved, so no GHS classification is given here.
ghs: []
source: hexcel-eu-ds
where: Page 6, Precautions for Use
- text: 'Acrylonitrile, the monomer of the PAN precursor, is the raw material of this fibre and is not the cured composite. PubChem reports the aggregated ECHA C&L notifications with the signal word Danger and hazard statements H225, H301, H311, H315, H317, H318, H331, H335, H350 and H411, including H350: May cause cancer.'
ghs: []
source: pubchem-acrylonitrile
where: PubChem CID 7855, Safety and Hazards, GHS Classification (aggregated ECHA C&L Inventory notifications)
failure_risks:
- mode: Hot-wet strength loss
trigger: Conditioning at 250 °F wet to equilibrium moisture content
consequence: Longitudinal tensile strength measured 327.96 ksi, against 371.08 ksi at room temperature dry (NCAMP lamina test).
severity: moderate
source: ornl-ncamp-2011
where: Section 2.1, Table 2-1, ETW and RTD measured columns
- mode: Use above the datasheet service envelope
trigger: Operation above 121 °C (250 °F)
consequence: The datasheet says the system was developed for environments up to 121 °C (250 °F). It gives no performance statement above that temperature.
severity: moderate
source: hexcel-eu-ds
where: Page 1, Description
handling:
- text: Store the prepreg frozen at -18 °C in a sealed moisture-proof bag. Shelf life is 12 months at -18 °C from date of manufacture (maximum).
source: hexcel-eu-ds
where: Page 6, Storage Life
- text: Tack life is 10 days at 23 °C (73 °F). Out life, the time between removal from the freezer and cure, is 30 days at 23 °C.
source: hexcel-eu-ds
where: Page 6, Storage Life
- text: Use clean disposable inert gloves to protect the operator and avoid contaminating the material and components.
source: hexcel-eu-ds
where: Page 6, Precautions for Use
mitigations:
- text: Performance testing should accompany alternative cure cycles to ensure suitability for the particular application.
source: hexcel-eu-ds
where: Page 5, Curing Conditions, note
uses:
- application: structures
device: Primary aerospace structures (unidirectional and woven prepreg)
example: Hexcel describes HexPly 8552 as a high performance tough epoxy matrix for use in primary aerospace structures.
source: hexcel-eu-ds
where: Page 1, Description
- application: structures
device: Honeycomb sandwich components
example: The datasheet gives a separate cure cycle for honeycomb sandwich components, at 3.2 bar gauge autoclave pressure against 7 bar gauge for monolithic parts.
source: hexcel-eu-ds
where: Page 5, Curing Conditions, honeycomb sandwich cure cycle
- application: structures
device: Space launcher and space and defence aircraft structures (typical uses)
example: The US edition lists space launchers and space and defence aircraft structures among typical uses of HexPly 8552.
source: hexcel-us-ds
where: Page 1, typical uses list, Space and Defense column
supply:
- subject: Carbon fibre precursor (polyacrylonitrile, PAN)
producers: []
critical_lists: []
substitutes: []
source: pmc-melt-spinnable-pan
where: 'Section 1, Introduction: ''acrylonitrile (AN) copolymers are the most frequently used precursors for the production of carbon fibers''. The review gives no country shares.'
- subject: Acrylonitrile (PAN monomer)
producers: []
critical_lists: []
substitutes: []
source: hexcel-10k-fy2024
where: 'Item 1, Business, Raw Materials and Production Activities: ''The primary raw material for PAN is acrylonitrile.'' No producer shares or critical-mineral listing were read for acrylonitrile.'
- subject: Carbon fibre (Hexcel PAN-based fibre)
producers: []
critical_lists: []
substitutes: []
source: hexcel-10k-fy2024
where: 'Item 1, Business, Raw Materials and Production Activities: ''We manufacture high performance carbon fiber from polyacrylonitrile precursor''; a new Decatur, AL line ''is expected to be qualified to produce carbon fiber for aerospace markets in 2028''. Item 1, Patents and Know-How: Salt Lake City carbon fibre and prepreg operations. No country shares are printed.'
media: []
documents:
- title: HexPly 8552 Product Data Sheet, EU edition
type: datasheet
url: https://www.hexcel.com/wp-content/uploads/2025/12/HexPly_8552_eu_DataSheet1.pdf
year: 2023
- title: HexPly 8552 Product Data Sheet, US edition
type: datasheet
url: https://hexcel.com/wp-content/uploads/2026/01/HexPly_8552_us_DataSheet.pdf
year: 2020
- title: 'Hexcel 8552 IM7 Unidirectional Prepreg 190 gsm and 35% RC: Qualification Material Property Data Report (NCAMP CAM-RP-2009-015 Rev A)'
type: report
url: https://thyme.ornl.gov/CFCrush/materials/uou/CAM-RP-2009-015_Rev_A_April_22_2011_Hexcel_8552_IM7_Uni_Data_Report.pdf
year: 2011
- title: LDEF SAMPLE experiment abstract (NASA NTRS 19940007012)
type: report
url: https://ntrs.nasa.gov/citations/19940007012
- title: Hexcel Corporation Form 10-K for fiscal year 2024 (SEC filing)
type: report
url: https://www.sec.gov/Archives/edgar/data/717605/000095017025014412/hxl-20241231.htm
year: 2025
- title: Acrylonitrile, PubChem CID 7855 (GHS classification)
type: database
url: https://pubchem.ncbi.nlm.nih.gov/rest/pug_view/data/compound/7855/JSON?heading=GHS+Classification
- title: Melt-Spinnable Polyacrylonitrile, An Alternative Carbon Fiber Precursor (Polymers, 2022)
type: paper
url: https://pmc.ncbi.nlm.nih.gov/articles/PMC9738362/
year: 2022
gaps:
- 'Supply: producer country shares, critical-mineral listings and manufacturing shares for IM7 fibre and HexPly 8552 were not found in the sources read. The Hexcel 10-K names the PAN precursor, acrylonitrile and the Decatur and Salt Lake City sites without shares, and the PMC review gives no percentage. The Hexcel contact page linked from the datasheet was not read.'
- 'Moisture uptake: no equilibrium moisture content percentage was found in the sources read. The NCAMP report describes the wet condition but prints no percentage.'
- 'Coefficient of thermal expansion: no value for IM7/8552 was found in the sources read.'
- 'Space environment: no atomic oxygen, UV, thermal-vacuum or flight result for IM7/8552 was found. The only space-related source is a NASA LDEF abstract that covers carbon fibre composites generally.'
- 'Safety data sheet: the HexPly 8552 SDS was not found by search, so hazard data for the cured or uncured prepreg are limited to a datasheet statement. The only GHS data are for acrylonitrile, the PAN monomer, from PubChem; they do not describe the composite.'
- 'NMS 128 Rev D material specification: the Wichita page returned no readable text to WebFetch, so specification limits were not used. The NMS 128/2 number printed in the NCAMP report was not added as a designation because NMS is not in the designation system list.'
- 'Canonical names: compressive strength, compressive modulus, short-beam shear, in-plane shear, fibre volume, cured ply thickness, cure temperature and cure pressure are not in property-canon.yaml. Short snake_case names were used; please review.'
- 'Two datasheet editions: the EU edition (2023) and the US edition (2020) are both cited, each for the values it prints. Metric values are taken from the EU edition; elongation and Poisson''s ratio come from the US edition, which prints no metric elongation.'
- 'Two products: the NCAMP report covers IM7/8552 at 190 gsm and 35% RC, and the datasheet covers 8552/35%/134. The two differ in areal weight and are not interchangeable.'
- 'Fibre volume: the NCAMP report prints 58.535 %vol (Method I) and 59.405 %vol (Method II); the datasheet nominal is 57.70 %. All three are kept with their sources.'
- 'Hot-wet and long-term ageing: no data beyond 250 °F wet or beyond the single NCAMP condition were found. The datasheet gives wet ILSS only at 25 °C.'
- Laminate-level results (open hole, filled hole, bearing, compression after impact) were not transcribed; the NCAMP report uses several layups and each would need its layup named.
- The NCAMP values were read from pdftotext table layout, not from the page image; the ETW and RTD column positions were checked against the column headers, but a visual check was not done.
sources:
hexcel-eu-ds:
title: HexPly 8552 Product Data Sheet, EU edition (Hexcel, copyright 2023)
id: Hexcel FTA-072-MC23
url: https://www.hexcel.com/wp-content/uploads/2025/12/HexPly_8552_eu_DataSheet1.pdf
year: 2023
kind: datasheet
license: Hexcel product data sheet (cited, not reproduced)
hexcel-us-ds:
title: HexPly 8552 Product Data Sheet, US edition (Hexcel, copyright 2020)
id: Hexcel US product data sheet, file dated 2026-01 on hexcel.com
url: https://hexcel.com/wp-content/uploads/2026/01/HexPly_8552_us_DataSheet.pdf
year: 2020
kind: datasheet
license: Hexcel product data sheet (cited, not reproduced)
ornl-ncamp-2011:
title: 'Hexcel 8552 IM7 Unidirectional Prepreg 190 gsm and 35% RC: Qualification Material Property Data Report'
id: NCAMP CAM-RP-2009-015 Rev A (NIAR, Wichita State University), April 22, 2011; FAA special project
url: https://thyme.ornl.gov/CFCrush/materials/uou/CAM-RP-2009-015_Rev_A_April_22_2011_Hexcel_8552_IM7_Uni_Data_Report.pdf
year: 2011
kind: report
license: NCAMP report hosted by ORNL (cited, not reproduced)
wiki-cfrp:
title: Carbon fiber reinforced polymer (Wikipedia; used for composition and history only)
id: Wikipedia, accessed 2026-11-01
url: https://en.wikipedia.org/wiki/Carbon_fiber_reinforced_polymer
year: 2026
kind: web
license: CC BY-SA 4.0
nasa-ldes-ntrs:
title: 'LDEF SAMPLE experiment: carbon fibre composite erosion in low Earth orbit (NASA NTRS abstract)'
id: NTRS 19940007012
url: https://ntrs.nasa.gov/citations/19940007012
kind: report
license: public domain (NASA)
hexcel-10k-fy2024:
title: Hexcel Corporation Form 10-K for fiscal year 2024 (SEC filing)
id: SEC EDGAR filing for CIK 717605, accession 0000950170-25-014412
url: https://www.sec.gov/Archives/edgar/data/717605/000095017025014412/hxl-20241231.htm
year: 2025
kind: report
license: public SEC filing
pubchem-acrylonitrile:
title: 'Acrylonitrile, PubChem CID 7855: GHS classification (aggregated ECHA C&L Inventory notifications)'
id: PubChem CID 7855
url: https://pubchem.ncbi.nlm.nih.gov/rest/pug_view/data/compound/7855/JSON?heading=GHS+Classification
kind: database
license: PubChem public database (NCBI)
pmc-melt-spinnable-pan:
title: 'Melt-Spinnable Polyacrylonitrile: An Alternative Carbon Fiber Precursor (Polymers, 2022)'
id: PMC9738362
url: https://pmc.ncbi.nlm.nih.gov/articles/PMC9738362/
year: 2022
kind: paper
license: open access (PMC)
license: CC-BY-4.0
updated: '2026-11-01'
review:
status: draft
method: assistant
checked_values: 36
note: Values read in this run from the text of the two Hexcel datasheets and the NCAMP report (pdftotext for PDFs); not re-read from page images. Supply and feedstock rows and the acrylonitrile hazard entry were read in this run from the Hexcel FY2024 10-K, the PubChem acrylonitrile record and a 2022 Polymers review.
story:
recipe:
line: HexPly 8552 is an amine-cured, toughened epoxy matrix supplied with carbon fibre. The unidirectional IM7 prepreg uses IM7 carbon fibre in a 12K tow at a nominal fibre volume of 57.70 %, with the rest of the laminate volume taken by the resin. Carbon fibre is made from a precursor polymer such as polyacrylonitrile (PAN), spun into filaments and carbonized (Wikipedia). The composite is cured in an autoclave under vacuum and pressure, following the cure cycle in the properties.
parts:
- name: IM7 carbon fibre
share: 57.70 % of laminate volume (nominal, unidirectional prepreg)
role: Carries most of the load along the fibre direction. The datasheet describes good translation of fibre properties into the laminate.
- name: HexPly 8552 epoxy matrix
share: Remainder of the laminate volume
role: Amine-cured, toughened epoxy that binds the fibres, transfers load between them and sets the controlled flow and service envelope described in the datasheet.
risk_groups:
- title: For people
level: 0
verdict: No GHS hazard classification found in the sources read
lead: The Hexcel datasheet points to a separate safety data sheet for this product, which was not retrieved. Hazard information here is limited to the datasheet precautions.
points:
- label: Uncured prepreg
line: The datasheet says the usual precautions for uncured synthetic resins and fine fibrous materials apply, and recommends clean disposable inert gloves.
- label: Cured composite
line: The sources read give no toxicology or dust data for the cured composite. That gap is listed under gaps.
- title: Hot and wet
lead: Moisture and heat lower the glass transition and the strength measured in the qualification tests.
points:
- label: Strength
line: Longitudinal tensile strength fell from 371.08 ksi at room temperature dry to 327.96 ksi at 250 °F wet, measured in NCAMP lamina tests.
- label: Short-beam shear
line: The datasheet prints 137 MPa dry and 115 MPa wet at 25 °C.
- label: Glass transition
line: The laminate glass transition is 406.43 °F dry and 321.41 °F wet by DMA. The neat resin is 200 °C dry and 154 °C wet in the datasheet. The two sets use different specimens and are not directly comparable.
- title: Handling and storage
points:
- label: Freezer storage
line: The prepreg is stored frozen at -18 °C, with a maximum shelf life of 12 months from manufacture, in a sealed moisture-proof bag.
- label: Working time
line: Tack life is 10 days at 23 °C. Out life, the time between removal from the freezer and cure, is 30 days at 23 °C.
why: HexPly 8552 IM7 is a carbon-epoxy prepreg for primary aerospace structures. It pairs IM7 carbon fibre with a toughened epoxy matrix and cures at 180 °C under pressure. The datasheet says the matrix gives good impact resistance and damage tolerance. An NCAMP qualification report prepared for an FAA special project records lamina test data for this material, so its strength and stiffness values come with a test record.
uses:
- where: Primary aerospace structures
line: Hexcel describes HexPly 8552 as a high performance tough epoxy matrix for use in primary aerospace structures. The US edition also lists space launchers and space and defence aircraft structures among typical uses.
- where: Honeycomb sandwich components
line: The datasheet gives a separate cure cycle for honeycomb sandwich components. It uses 3.2 bar gauge autoclave pressure, against 7 bar gauge for monolithic parts.
can_do:
- label: Stiffness
benchmark: elastic_modulus
value: 164 GPa
line: The 0° tensile modulus of the unidirectional IM7 prepreg is 164 GPa at 25 °C dry, per the Hexcel EU datasheet. The AS4 version of the same resin prints 141 GPa.
- label: Strength
benchmark: ultimate_tensile_strength
value: 2724 MPa
line: The 0° tensile strength is 2724 MPa (395 ksi) at 25 °C dry, per the Hexcel EU datasheet.
- label: Heat tolerance
benchmark: glass_transition_temperature
value: 200 °C dry, 154 °C wet
line: The neat resin glass transition is 200 °C dry and 154 °C wet, per the Hexcel EU datasheet. The NCAMP laminate reads 406.43 °F dry and 321.41 °F wet by DMA, which is a different specimen and method.
- label: Service environment
benchmark: max_service_temp
value: 121 °C (250 °F)
line: The datasheet says the system was developed to operate in environments up to 121 °C (250 °F).
compare: Against AS4 carbon fibre in the same HexPly 8552 matrix, IM7 gives a higher 0° tensile strength (2724 MPa against 2207 MPa at 25 °C dry) and a higher 0° tensile modulus (164 GPa against 141 GPa), per the same Hexcel EU datasheet table. The IM7 fibre is slightly less dense, at 1.77 g/cm3 against 1.79 g/cm3 for AS4. The short-beam shear strength is slightly higher for IM7 (137 MPa against 128 MPa dry at 25 °C). The table below compares the tensile strength, tensile modulus and density of IM7/8552 with the other properties in this record that a like-for-like comparison can use.
compare_rows:
- label: 0° tensile strength, 25 °C dry
benchmark: ultimate_tensile_strength
- label: 0° tensile modulus, 25 °C dry
benchmark: elastic_modulus
- label: Fibre density
benchmark: density
handling:
- Store the prepreg frozen at -18 °C, sealed in a moisture-proof bag. Shelf life is 12 months from manufacture.
- Tack life is 10 days at 23 °C. Out life is 30 days at 23 °C between removal from the freezer and cure.
- Use clean disposable inert gloves, as the datasheet advises.
- 'Cure with the printed cycle: 7 bar gauge for monolithic parts and 3.2 bar gauge for honeycomb sandwich. Performance test any alternative cure cycle.'
good_for:
- Primary aerospace structures that need high 0° strength and stiffness. The unidirectional prepreg gives 2724 MPa and 164 GPa at 25 °C dry.
- Parts that need a test record. The NCAMP report gives lamina data with normalization to cured ply thickness.
watch_out:
- Hot-wet strength loss. Longitudinal tensile strength falls from 371.08 ksi at room temperature dry to 327.96 ksi at 250 °F wet.
- Service envelope of 121 °C (250 °F). The datasheet does not give a higher operating limit.
- Glass transition values differ by method. The neat resin reads 200 °C dry and 154 °C wet; the laminate reads 406.43 °F dry and 321.41 °F wet.
- Space exposure. No IM7/8552 atomic oxygen, UV or thermal-vacuum result was found; the one NASA abstract covers carbon fibre composites generally.
verdict: 'IM7/8552 is a well-documented aerospace prepreg: the datasheets and the NCAMP report give its 0° strength and stiffness and its hot-wet values. Its hot-wet strength and the 121 °C (250 °F) service envelope should be checked against the application.'
References
Every number above carries a reference number. Click one to see the source and where in it the value comes from.
| # | Source | Type | Year | Used for |
|---|---|---|---|---|
| HexPly 8552 Product Data Sheet, EU edition (Hexcel, copyright 2023) | datasheet | 2023 | 36 values | |
| HexPly 8552 Product Data Sheet, US edition (Hexcel, copyright 2020) | datasheet | 2020 | 3 values | |
| Hexcel 8552 IM7 Unidirectional Prepreg 190 gsm and 35% RC: Qualification Material Property Data Report | report | 2011 | 12 values | |
| Carbon fiber reinforced polymer (Wikipedia; used for composition and history only) | web | 2026 | 0 values | |
| LDEF SAMPLE experiment: carbon fibre composite erosion in low Earth orbit (NASA NTRS abstract) | report | 1 value | ||
| Hexcel Corporation Form 10-K for fiscal year 2024 (SEC filing) | report | 2025 | 2 values | |
| Acrylonitrile, PubChem CID 7855: GHS classification (aggregated ECHA C&L Inventory notifications) | database | 1 value | ||
| Melt-Spinnable Polyacrylonitrile: An Alternative Carbon Fiber Precursor (Polymers, 2022) | paper | 2022 | 1 value |
Updated