Effect of Composition Variation on Isothermal Rapid Curing Resins for Aerospace Applications

To meet the projected demand for single-aisle composite aircraft in 2040, the production rate of
these aircraft will need to increase by four to six times what is currently achievable. A composite
manufacturing process with the potential to enable the targeted rates is isothermal resin infusion
where infusion and cure occur at the same temperature. However, presently there is not an
accepted aerospace-grade resin that can support this isothermal infusion process and maintain
acceptable resin properties. Therefore, resin development initiatives have designed anionic
catalyzed epoxy systems capable of isothermal infusion and rapid cure at a temperature below
100 ˚C in one hour. High-performance aerospace properties are achieved after undergoing a
freestanding post-cure. The resins facilitate faster, energy efficient production cycles by reducing
the time and temperature required for cure and eliminating temperature ramps typically required
of materials used in the aerospace industry. This work discusses several of the
developed resin systems and the impact of varying composition on rheological, thermal, and
mechanical properties. Carbon fiber composites were fabricated for one composition by resin
transfer molding to demonstrate the potential of these isothermal, rapid cure systems for meeting
industry needs.