Keynote: Polyimide Aerogels: Overview and Outlook for Future Space and Terrestrial Applications at NASA

Abstract

Aerogels are low density solids with nanoscale porosity imparting some extraordinary properties, including very low thermal conductivity, very high surface areas and dielectric constants approaching that of air. Because of these properties, the potential applications of aerogels are seemingly endless and include superior insulation materials for everything from building and construction to high performance clothing, catalyst supports, low dielectric substrates, sensor platforms, materials for environmental remediation, drug delivery materials, tissue scaffolds and many others. The well-studied, silica aerogels, however, are very fragile materials, making many of these applications out of reach. In the last decade, aerogels made from many other materials have emerged with nanoscale porosity, high surface area and low density similar to silica, especially when made using a similar process—gelation followed by supercritical fluid ex-traction. Of all the materials studied in the form of aerogels, those derived from polymers have been reported with the best mechanical properties, making all of the potential applications of aerogels closer to reality. As a class of materials, polymer aerogels have many of the same properties as silica aerogels, including high surface area, low density, low dielectric constants, and low thermal conductivity. However, many polymer aerogels also possess mechanical properties far exceeding those of silica aerogels, making them much more applicable as low dielectric substrates, durable insulation, or lightweight multifunctional structures. The use of engineering polymers, such as polyimide and polyamide, as the aerogel backbone, adds the potential for higher use temperatures, combined with good mechanical properties. In addition, by tuning the backbone chemistry, polyimide and polyamide aerogels provide an endless ability to dial in properties for specific aerospace and other applications. This presentation will give an overview of the synthesis methodology, physical and mechanical properties and finally, several impactful aerospace applications for which NASA has used polyimide based aerogels.

About the Speaker

Dr. Rocco Viggiano is a polymer chemist in the Materials Chemistry and Physics Branch of the Materials and Structures division at the NASA Glenn Research Center, where he has been since his start in September of 2015. He earned Bachelor of Science degrees in Chemistry and in Plastics Engineering as well as a minor in Physics at Penn State University. He completed his Ph.D. in Macromolecular Science and Engineering from Case Western Reserve University in 2015 under the direction of Dr. David Schiraldi and Dr. Mary Ann Meador with a focus on the synthesis and processing of aerogels. During his time at NASA, he has developed novel aerogel chemistries as well as battery components. These have included the development of more dimensionally stable polyimide aerogels at elevated temperatures, thermally reversible polyimide gel chemistries for carbon nanotube wire coating and a non-flammable separator/electrolyte composition for lithium-ion batteries.