Amplitude Spectrum Approach in Dynamic FT-IR Spectroscopy of Uniaxially Oriented Poly(Ethylene Terephthalate) Films. Part I: Draw Ratio Dependence

Abstract

A method of data manipulation using the dynamic magnitude spectrum and the static absorbance spectrum is applied to uniaxially drawn poly(ethylene terephthalate) films with five different draw ratios for the evaluation of the amplitude of dynamic structural changes under a sinusoidal strain at the level of a functional group. This analysis revealed that, in the drawn film, the skeletal structures, such as the C–O bond in the ethylene glycol unit and the phenyl ring, are susceptible to deformation by mechanical stretching, while the dynamic structural changes around the methylene group are small. It was assumed that the backbone of the polymer is responsible for the change of the mechanical properties induced by the drawing of the film.