A spectroscopic study of polyimide films exposed in low earth orbits

Abstract

The results of electronic and IR spectroscopic studies on polyimide films of the PM-1E and Kapton 100 HN brands exposed over 28 and 42 months in low Earth orbits are reported. The open outer films after exposure, especially for 42 months, became nontransparent in the visible spectral region, which was due to the formation of spatially oriented light-scattering structures on the external surface of the films. Changes in the IR spectra over the range 500-2000 cm -1 indicated polymer-chain scission, degradation of the imide cycle, and oxidation of polyimide. The determining role in spectral changes over the IR range 2500-4000 cm-1 for the films exposed for 42 months is played by scattering of IR radiation. Crystallization in the thin surface layer of polyimide was revealed by the attenuated total reflection technique. © 2005 MAIK "Nauka/Interperiodica".