Infrared absorption spectra and structure of polyethylene terephthalate

Highly doubly oriented specimens of polyethylene terephthalate were studied by the methods of x‐ray diffraction and of infrared microspectroscopy. The sample for the microspectroscopy was embeded in n‐butyl methacrylate resin and cut perpendicularly to the stretching direction by a microtome. The spectra by the tilting method were also taken for the measurements of the pleochroism of the intense bands. Spectral measurements at various temperatures have been also made to obtain some additional information. It was confirmed that the molecular plane of the polymer (the plane of the benzene ring) is nearly parallel to the rolled plane. The assignments of the main bands are discussed.