Polyimide foam can be used as an insulator (such as for rocket fuels) and acoustic damper. NASA can use these functionally graded polyimide foam for ducting, duct/piping insulation, structural components, and strengthening of hollow components while remaining lightweight. Polyimide foam is lightweight, thermal, and acoustic insulation material. It provides significant weight reductions and is inherently fire resistance, low surface burn, low smoke development, and no significant toxic offgasing. It improves appearance and no fibrous shake out as compared to fibrous materials. It usually provides less waste and faster installation which means lower installed cost. It can be use for thermal/acoustic insulation, noise transmission loss blanket, duct insulation, and duct liner applications.