When turbine inlet temperatures hit 1,600°C, only advanced carbon fiber prepreg with Tg > 200°C can survive. The new breed of phenylethynyl-terminated (PETI) epoxy prepregs is redefining aerospace thermal limits.
The Tg Paradox
Standard aerospace epoxy carbon fiber prepreg (Tg=180°C) loses 80% stiffness at 200°C. Cytec’s CYCOM® 977-3 (Tg=210°C) retains 72% modulus at 250°C through its multi-ring aromatic backbone, proven in Dassault Rafale’s engine nacelles.
Hypersonic Matrix Design
For Mach 5+ vehicles, carbon fiber prepreg requires:
Tetrafunctional epoxies (EPON 1031)
Bismaleimide hybrids
Ceramic nanofillers (20nm SiC)
Northrop Grumman’s HAMMER carbon fiber prepreg achieves Tg=275°C with 45% lower thermal expansion than aluminum.
Cryo-Performance Breakthrough
SpaceX’s Starship fuel tanks demand carbon fiber prepreg surviving -196°C to +150°C cycles. Toray’s 3900-2B prepreg shows 0.003% microcrack density after 100 thermal shocks – 10x better than legacy materials.
Flame Toxicity Revolution
FAA 25.853 mandates <100 HCN ppm in smoke. New carbon fiber prepreg like Gurit’s SA80 incorporates phosphazene fire retardants that cut HCN emission to 28 ppm while increasing LOI to 45%.
Out-of-Autoclave (OOA) Revolution
NASA’s Artemis moon lander uses carbon fiber prepreg with engineered voids:
0.5% porosity for thermal insulation
Controlled void morphology via POSS nanoparticles
This enables 4m-diameter cryotanks cured at 90°C/1 bar with 0.95 laminate quality factor.
Radiation Shielding Integration
For GEO satellites, carbon fiber prepreg loaded with 5% boron nitride nanotubes attenuates 200 MeV protons by 80% while adding just 3% mass penalty. Boeing’s 702X bus uses this as primary structure.
Sustainable High-Tg Solutions
Bio-based carbon fiber prepreg now hits Tg=195°C:
Anhydride hardener from rosin acids
Lignin-derived epoxy monomers
SGL’s ACUTE™ prepreg reduces carbon footprint by 62% versus petroleum-based equivalents.