Aerogels are highly porous solids having low density, high surface area, low dielectric constant, and low thermal conductivity. In the past few years, cross-linked polyimide aerogels have been extensively studied. Depending on the structure of the polyimide backbone, flexible, foldable, non-flaking thin films can be cast, or stiffer thick parts can be mold with good mechanical properties. Their unique features have made them good candidates for various aeronautic and aerospace fields including lightweight substrate for antenna, or multi-layer insulating films recently tested for inflatable decelerators used in entry, decent and landing operations. However, high material cost still remains an issue. The cross-linkers used to make these aerogels such as octa (aminophenyl)-silsesquioxane (OAPS) are quite expensive, or like 1,3,5-tris(4-aminophenoxy) benzene (TAB), are custom made. The main approach of this study is to use a triisocyanate, N3300A, as a cross-linker to improve the flexibility of the polyimide aerogels by inserting urethane/urea linkages into the network. In addition, N3300A is a low cost, commercially available material. Moreover, with the isocyanate reactive groups, a more stable polyimide solution with amine or hydroxyl end-groups can potentially be preserved for an extended period before being cured.

Development of flexible polyimide-urea aerogels cross-linked with a triisocyanate

249th National Meeting (2015)

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