NASA-developed polyimide aerogels are 500 times stronger than conventional silica aerogels. The innovative aerogels represent a revolutionary advance over fragile silica aerogels because they are highly flexible and foldable in thin film form. As a thin film, they can be used to insulate industrial pipelines, automotive shields, and temporary housing structures, and can be used within protective clothing such as firefighting jackets, space suits, and parkas. As a thicker part, they can be easily molded to a shape, or sanded and machined to provide insulation as well as mechanical support. No other aerogel possesses the compressive and tensile strength of the NASA innovation while still retaining its ability to be flexibly folded to contour to whatever shape is needed.
Aerogels are highly porous, low-density solids with extremely small pore sizes, making them superior insulators. However, the most studied silica aerogels are fragile. NASA’s Glenn Research Center synthesized polyimide aerogels by cross-linking through an aromatic triamine or polyhedral oligomeric silsesquioxane, and chemically imidizing at room temperature. The resulting product is a cross-linked polyimide aerogel that retains the positive characteristics and strength of polyimide materials, and adds the beneficial properties of aerogels without the brittle and fragile nature of silica aerogels.
Current silica aerogels on the market are available in particulate form or as a composite blanket. These aerogels are fragile and shed dust particles in use. The cross-linked polyimide aerogels have much better mechanical properties than silica aerogels and do not shed dust particles. They have low thermal conductivity, are heat-resistant up to 200 to 300 °C for long-term use, and are moisture-resistant. The thermal conductivity is 2 to 10 times improved performance over polymer foams in ambient condition, and up to 30 times improved performance in vacuum conditions.
The cross-linked aerogels can be fabricated or machined into thick net shape parts, which are strong and stiff, or cast as thin flexible films with good tensile properties. Extremely customizable, the innovation can be formed into whatever configuration is required (e.g., wrapped around a pipe, sewn into protective clothing, or molded into a panel to act as a heat shield in a car) so it has an advantage over other aerogels that exist in block form and must be modified or chemically altered to function as a formfitting insulation.
Potential applications include thermal insulation for refrigeration, housing, industrial pipelines, automotive, and medical supplies; lightweight sandwich structures to reduce the weight of automobiles and aircraft; low dielectric materials for antennas (aircraft, cell phones, satellites, etc.); filtration media for air and water purification and gas separation; and flexible, thin insulation for protective clothing, space suits, and temporary shelters.