Supervisory chemistMember of ASTM, Center for Materials Science, National Bureau of Standards, Washington, DC
The Fourier transform infrared (FT-IR) technique is replacing conventional dispersive instruments in the acquisition of IR spectroscopic data. For standards organizations this implies that existing standard test methods involving IR spectral analysis need to be modified. In an FT-IR system all spectral information is contained in the interferogram produced by scanning the Michelson interferometer. The factors controlling spectral resolution and sensitivity are, therefore, different from those governing these properties of dispersive instruments. The FT-IR technique has the advantages of greater signal-to-noise ratio and digitized data that open up new areas of application as well as provide greater sensitivity in the more traditional uses of IR spectroscopy. A review of the field of vibrational spectroscopy of polymers identifies time-dependent phenomena and characterization of structural imperfections as two areas likely to see major advances as a result of FT-IR.
Examples of the use of FT-IR in polymer research are given to illustrate the potential of the technique. At the National Bureau of Standards FT-IR has been used to determine the role of chain scission in the mechanical degradation of polymers, to measure the extent of chemical reactions during processing polymer composites, and to characterize polymeric materials.
Paper ID: JTE11418J