Nanotechnology Now - News Story: Formulating challenge: Creating better epoxies for vacuum-infused aerospace parts

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March 17th, 2008

Formulating challenge: Creating better epoxies for vacuum-infused aerospace parts

Abstract:
More attention is being focused on fabricating processes for aircraft structures that can save time and money and improve efficiency while yielding high-quality parts. Historically, nearly all aircraft designers have assumed autoclave cure as the norm, despite the well-documented cost and time advantages of out-of-autoclave processing. The formulation of epoxy-based resin systems that can be used to vacuum infuse dry fibers or preforms holds great promise for producing large, complex composite parts with less than 1 percent void content and controllable resin/fiber ratio. Vacuum infusion permits the use of inexpensive "soft" tooling and ambient/near-ambient curing to reduce autoclave processing costs and save energy.

A key to formulating one- and two-part epoxy resin systems for aerospace vacuum infusion is balancing viscosity with in-service performance. Huntsman Advanced Materials (The Woodlands, Texas), a pioneer with its trademarked RenInfusion epoxies for infusion processes, has found that through the use of nano-based toughening agents, new-generation infusion epoxies can be produced with physical property combinations that once were apparently diametrically opposed. For example, epoxy formulations have been developed that can be infused at temperatures less than 120ºF (49ºC) for two-part systems, and 180ºF (83ºC) for one-part systems, says Huntsman senior chemist Jim Hoge, delivering adequate pot life, a high glass transition temperature (Tg), and good toughness with high modulus. System dry Tg's are in the 280ºF to 350ºF (138ºC - 177ºC) range.

Source:
compositesworld.com

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