Kapton

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Kapton is a polyimide film developed by DuPont which can remain stable in a wide range of temperatures, from -269 °C to +400 °C (-452 °F to 752 °F; compare lower bound with absolute zero, -273 °C or -460 °F). Kapton is used in, among other things, flexible printed circuits (flexible electronics) and spacesuits. The chemical name for Kapton H and HN is poly(4,4'-oxydiphenylene-pyromellitimide. It is produced from a diamine and pyromellitic acid by a condensation reaction producing water as byproduct.

Kapton insulated wiring has been widely used in civil and military avionics (electrical wiring for aircraft) because of its very light weight compared to other insulator types as well as good insulating and temperature characteristics. However it was soon found to have very poor resistance to mechanical wear, mainly abrasion within cable harnesses due to aircraft movement. Many aircraft models have had to undergo extensive rewiring modifications, sometimes completely replacing all the Kapton-insulated wiring, because of short circuits caused by the faulty insulation.

According to a NASA internal report, Space Shuttle "wires were coated with an insulator known as Kapton that tended to break down over time, causing short circuits and, potentially, fires.[1]" The NASA Jet Propulsion Laboratory has considered Kapton as a good plastic support for solar sails because of its long duration in the space environment (J. L. Wright, Space Sailing, Gordon and Breach, 1992).

Kapton is also commonly used as a material for windows of all kinds at x-ray sources (synchrotron beam-lines and x-ray tubes) and x-ray detectors. Its high mechanical and thermal stability as well as its high transmittance to x-rays make it the preferred material. It also does not suffer from radiation damage.^[1] Another prominent material for these purposes is Beryllium.