Thermally Resistant Polyimide Seals

There is an interest in new designs of solid propellant rockets which can provide greater impulse and thrust. Taking advantage of higher burn temperatures could facilitate these improvements, but it also requires rocket material components, such as dynamic seals, to be redesigned to meet the higher thermal demands. Dynamic seals are typically found in movable pintle valves inside a rocket nozzle that control the effective area of the throat for thrust variations. Conventional sealing materials are fluorocarbon elastomers that have operating temperatures up to 600 °F. Herein, we propose the preparation and use of thermosetting and fluorinated polyimides with high glass transition temperatures that are expected to excel in the temperature of 600 °F. The synthesized polyimides will be characterized and tested to determine their thermal stability, tensile properties, compression strength, friction, compression set, and thermal expansion. Well-performing candidates will be investigated via molding of desired articles. Approved for Public Release | 21-MDA-11013 (19 Nov 21)