resin systems for advanced composites Product Data Sheet Description HexPly® F655™ is a bismaleimide resin that cures via an addition reaction in a toughened two-phase thermoset matrix with no condensation by-products. HexPly® F655™ is a controlled flow polyimide resin system designed for alternative processing capabilities such as co-curing over honeycomb core, compression molding, as well as standard autoclave processing. Features Uncured ¥¥Controlled flow ¥¥Process working life greater than 20 days Cured ¥¥High laminate mechanical strengths and strains ¥¥High strength retention at 450°F (232°C) dry and 350°F (177°C) wet ¥¥Improved compression after impact properties ¥¥Void-free thick laminate processability ¥¥Void-free thick laminate co-cure processing over honeycomb core ¥¥Long-term service life to 400°F (204°C) ¥¥Excellent electrical properties Neat Resin Properties Specific gravity 1.25 Tg dry* 550°F (288°C) Tg wet* > 400°F (204°C) Equilibrium moisture absorption 4.1% Coefficient of thermal expansion Temperature range 75–482°F = 2.66 x 10-5 in/in/°F 24–250°C = 4.78 x 10-5 mm/mm/°C Temperature range 347–482°F = 3.55 x 10-5 in/in/°F 175–250°C = 6.32 x 10-5 mm/mm/°C Fracture toughness, K1C 1.25 ksi in (1.37 MPa m) Dynamic Viscosity Analysis 109 * Test method: DMTA, E" peak

resin systems for advanced composites Product Data Sheet Neat Resin Hygrothermal Behavior Inverse Absolute Temperature: 1/T Cure Procedure Thin Laminates: ≤ 0.50” (1.27 cm) A. Apply vacuum of 22 inches Hg (74 kPa) minimum. B. Heat to 270 ± 5°F at 2–4°F/minute (132°C at 1.2–2.4°C/minute). Apply 85 ± 5 psig (586 kPa). C. Dwell at 270 ± 5°F (132°C ± 3°C) for 30 ± 5 minutes. Release vacuum. D. Heat to 375°F at 2–4°F/minute (191°C at 1.2–2.4°C/minute); cure 4 hours. E. Cool to 150°F at 5°F/minute (66°C at 3°C/minute) before releasing pressure. Thick Laminates: > 0.50” (1.27 cm) Laminates may be cured...

HexPly® F655resin systems for advanced composites ■TM Note: Carbon tapes may be produced with various carbon fiber types and tow sizes. In designating tape, the second digit represents tow size and the third digit: represents fiber source. Consult your nearest Hexcei Sales Representative for additional information. Physical Properties Dielectric Properties * Testing method: ASTM D2520 Copyright © 2020 - Hexcel Corporation - All Rights Reserved 3

HexPly® F655resin systems for advanced composites ■TM Laminate Mechanical Properties 1-33 (9.2) Copyright © 2020 - Hexcel Corporation - All Ri

HexPly® F655resin systems for advanced composites ■TM Copyright © 2020 - Hexcel Corporation - All Rights Reserved 5

resin systems for advanced composites Product Data Sheet Storage HexPly® F655™ prepreg should be sealed in a polyethylene bag and refrigerated, preferably below 32°F (0°C). Following removal from refrigerated storage, allow the prepreg to reach room temperature before opening the polyethylene bag to avoid moisture condensation. Shelf life: 12 months at 0°F (–18°C), 6 months at 40°F (4°C) (maximum, from date of manufacture). Shipping Prepreg fabric and tape are generally shipped in sealed polyethylene bags in insulated containers packed with dry ice. Disposal of Scrap Disposal of this material...