INFRARED DETERMINATION OF CONFORMERS OF POLY(ETHYLENE-TEREPHTHALATE)

An infra-red spectroscopic method is described for analysing quantitatively the conformers of the ethylene glycoxy moiety of poly(ethylene terephthalate), in the amorphous and crystalline regions. This method uses spectral band reconstruction of the profiles of either the 382 cm-1 band or the 1020 cm-1 band for a series of specimens annealed at different temperatures. Consistent results were obtained from both bands for the compositions of the three conformers, i.e. the trans conformer in the crystalline state and the trans conformer and the gauche conformer in the amorphous state. This demonstrates the reliability of the method proposed.