Analysis of pigmented polymer coatings with radiofrequency glow discharge optical emission spectrometry

Abstract

With a radiofrequency (r.f.) source, glow discharge optical emission spectrometry is capable of depth-profiling materials such as the pigmented polymers used on pre-painted steel. A method is now available for converting the recorded, qualitative r.f. depth-profiles into quantitative depth-profiles of concentration versus depth. The paper reports the results from the first test programme of the new method. The method is tested here with a range of laboratory prepared polymers with known pigment loadings. Samples include various concentrations of the principle white pigment, rutile, in the polymer, followed by a set with a range of mixed red and white pigments. The ability of the method to determine the pigment loadings and to distinguish the different pigments is assessed.