The Determination of Trace Inorganic Contaminants in Polyimides

Several techniques capable of measuring inorganic contaminants in the ppm to ppb range have been used to analyze both polyimides and their aqueous extracts for mobile ions. The techniques include plasma spectroscopy, ion chromatography and neutron activation analysis. Their combination has shown that the most hostile mobile ions present are alkali metal ions. While halide ions are present in bulk polymer, they are not mobile. The techniques, their limitations, and possible contamination sources are discussed.