thumb|structure of poly-oxydiphenylene-pyromellitimide thumb|kapton insulating pads for mounting electronic parts on a heat sink  thumb|kapton tapes, three rolls of different widths kapton is a polyimide film developed by dupont that remains stable across a wide range of temperatures, from â269 to +400 Â°c (â452 â 752 Â°f / 4 â 673 k). kapton is used in, among other things, flexible printed circuits (flexible electronics) and thermal micrometeoroid garments (the outside layer of space suits). the chemical name for kapton k and hn is poly (4,4'-oxydiphenylene-pyromellitimide). it is produced from the condensation of pyromellitic dianhydride and 4,4'-oxydiphenylamine. 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 (200â300 Â°c, 473â573 k). ==usage== the thermal conductivity of kapton at temperatures from 0.5 to 5 kelvins is rather high for such low temperatures, Îº = 4.638Ã10â3 t0.5678 wÂ·mâ1Â·kâ1. this, together with its good dielectric qualities and its availability as thin sheets have made it a favorite material in cryogenics, as it provides electrical insulation at low thermal gradients. kapton is regularly used as an insulator in ultra-high vacuum environments due to its low outgassing rate. ===aircraft=== kapton-
Aerospace_materials Dielectrics Flexible_electronics