Anisotropy of IR absorption of an extruded polyethylene terephthalate film

Abstract

The method of attenuated total reflection (ATR) IR spectroscopy has been used to shed light on the anisotropy of absorption in three main directions for extruded PETP films to determine the state of orientation and the crystallinity in the surface region and in the bulk of the polymer. An analysis of the behaviour of spectral distribution of phase bands for absorption in polarized and nonpolarized light shows that there is preferential orientation of macromolecular axes along the normal to the film surface. A study of changes in the relative intensities of the phase bands points to a higher degree of crystallinity in the volume than in the surface region.