No abstract

Transmission micro-FT-IR (Fourier transform infrared) and photoacoustic (PAS) FT-IR analysis have been combined to determine the oxidation profiles of various photooxidized polyisoprene-polystyrene copolymers. It is shown that only the polyisoprene phase is oxidized. The front photooxidized layers (0–22 μm) are analyzed by PAS, while the bulk (11–150 μm) is characterized by cross-sectional analysis of microtomed layers. A good agreement between the two methods is found in the region where the analyzed layers overlap (11–22 μm). The extent of the oxidation was determined by monitoring the ratio between the intensity of the carbonyl absorbance at 1718 cm−1 and the absorbance at 1600 cm−1. The results given in this article show that PAS FT-IR can be a rapid and nondestructive technique of quantitative characterization of the surface degradation of aged polymers.