Two-dimensional correlation analysis study of the photo-degradation of poly(ethylene terephthalate) film

The photo-degradation of poly(ethylene terephthalte) (PET) film was investigated in detail using ultraviolet–visible (UV–visible) spectroscopy, Fourier transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA) and two-dimensional (2D) correlation analysis. The analysis of 2D FTIR correlation spectra led to the identification of photoproducts: esters, peresters and benzoic acids. The photo-degradation of PET films strongly influences the spectral changes of the ester linkages as well as the CH2 groups adjacent to the ester groups. In addition, the spectral change of CH2 groups occurred before that of terephthalte groups.