Kapton is a polyimide film used in flexible printed circuits (flexible electronics) and space blankets, which are used on spacecraft, satellites, and various space instruments. Invented by the DuPont Corporation in the 1960s, Kapton remains stable (in isolation) across a wide range of temperatures, from . Kapton is used in electronics manufacturing, space applications, with x-ray equipment, and in 3D printing applications. Its favorable thermal properties and outgassing characteristics result in its regular use in cryogenic applications and in situations where high vacuum environments are experienced. History Kapton was invented by the DuPont Corporation in the 1960s. The name Kapton is a registered trademark of E. I. du Pont de Nemours and Company. Chemistry and variants Kapton synthesis is an example of the use of a dianhydride in step polymerization. The intermediate polymer, known as a poly(amic acid), is soluble because of strong hydrogen bonds to the polar solvents usually employed in the reaction. The ring closure is carried out at high temperatures of . The chemical name for Kapton K and HN is poly (4,4'-oxydiphenylene-pyromellitimide). It is produced from the condensation of pyromellitic dianhydride (PMDA) and 4,4'-oxydiphenylamine (ODA). Kapton E is a mix of two dianhydrides, PMDA and biphenyltetracarboxylic acid dianhydride (BPDA), and two diamines, ODA and p-phenylenediamine (PPD). The BPDA component adds greater dimensional stability and flatness in flexible circuitry applications. Kapton E offers reduced coefficient of thermal expansion (CTE), reduced moisture absorption, and reduced coefficient of hygroscopic expansion (CHE) compared to Kapton H. Characteristics Kapton remains stable (in isolation) across a wide range of temperatures, from . The thermal conductivity of Kapton at temperatures from 0.5 to 5 Kelvin is rather high for such low temperatures, κ = 4.638×10−3 T0.5678 W·m−1·K−1. Kapton insulation ages poorly: an FAA study shows degradation in hot, humid environments or in the presence of seawater. It was 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. Kapton-wire degradation and chafing due to vibration and heat has been implicated in multiple crashes of both fixed wing and rotary wing aircraft, with loss of life. 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