Recent Developments in Polymer Analysis and Characterization. I. Spectral Methods

III. SUMMARY

Several spectrometric techniques for the analysis and characterization of polymers are critically reviewed. Infrared spectrophotometric methods for the determination of ethylene and propylene sequence distributions in ethylene-propylene copolymers (EPM) are discussed. Major problems are the evaluation of group absorptivities and the resolution of overlapped bands in the —CH₂—and—CH₃ rocking and wagging region of the spectrum used for these measurements. The relative merits of using digitized spectra and a least squares curve-fitting technique for resolving the absorption band parameters are presented. Various infrared spectrophotometric methods for determination of EPM composition are discussed and compared. Advantages of using the new laser Raman scattering techniques for the characterization and vibrational analysis of polymers are mentioned. Some very new techniques which offer exciting promises in the analysis and characterization of polymers are cited. These include C¹³ nuclear magnetic resonance by Fourier transform pulsed techniques, a new polymer mass spectrometer for studying macroions, electron spectrometry (ESCA).