Vibrational Spectroscopy of Polymers

Abstract

Vibrational spectroscopists have generally had two experimental techniques, IR absorption and Raman scattering, available for probing the structure of polyatomic molecules. However, despite its potential usefulness, Raman spectroscopy has traditionally been pursued in only a few laboratories, principally because of the lack of a suitable source of exciting radiation. At the same time, IR spectrometers, sampling devices, and sample handling techniques have been developed and refined to the point where spectra in the mid and near IR regions may now be readily obtained from commercial instruments on a rather routine basis. As a result, virtually all laboratories concerned with molecular structure, and particularly those concerned with polymer characterization, are equipped with IR spectrometers and the importance of IR spectroscopy in polymer characterization can hardly be disputed. Infrared spectroscopy is widely used to identify polymers and to determine crystallinity, conformation, end groups, branching, cross-linking, hydrogen bonding, and fold structure of polymers and composition and sequence distribution of copolymers.