Comparison of polystyrene IR spectra obtained by the T, R, ATR, and DR methods

Abstract

The results of measuring the spectra of polystyrene samples in the IR range (4000–400 cm^–1) obtained by transmission, specular reflection, frustrated total internal reflection, and diffuse reflection have been compared. Polystyrene samples in the form of a thin film, a bulk sample, and foamed polystyrene have been investigated. The frequencies of the strongest bands in the spectra obtained by the methods under comparison are shown to depend on the anomalous dispersion in the vicinity of these bands and the specific features of structural chemical composition of the polystyrene–air interfaces. The presence of these interfaces is most pronounced in the reflection methods.