Polyimide foam is a foam designed by NASA, manufactured by Boyd Corp. in Magnolia, Arkansas, and marketed under the name SOLIMIDE. Its primary purposes are as an insulator (such as for rocket fuels) and acoustic damper. NASA engineered the product to have relatively low outgassing (a problem in vacuum and aboard spacecraft), desirable thermal and acoustic performance, as well as uniformity during distribution and application. Typical uses of the foam include ducting, duct/piping insulation, structural components, and strengthening of hollow components while remaining lightweight.
In addition to thermal and acoustic properties, SOLIMIDE is fire resistant, lightweight and non-toxic.
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Polyimide foam Wikipedia(Text) CC BY-SA