Analysis of Carbon Black-Filled Polymers by Vibrational Spectroscopy

Abstract

Carbon black-filled polymers are among the most challenging samples that an analyst may be called upon to identify. In this paper three novel methods of obtaining vibrational spectra from four different carbon black-filled polymers are evaluated: transmission infrared spectroscopy using a diamond anvil cell, Raman spectroscopy using 780-nm excitation, and inelastic neutron scattering. Overall, none of the three methods used in this work was totally satisfactory, but for most purposes infrared spectroscopy provides the best results in terms of spectrometer accessibility and the availability of suitable reference collections. Raman spectroscopy was successful only with one of the four polymers. Inelastic neutron scattering (INS) was successful in obtaining a spectrum with all four materials, but this success occurred only with respect to the hydrogenic part of the polymer, and, for many materials, it is the heteroelements, O, S, and halogens, that determine the important physical properties of the compound. For both Raman spectroscopy and INS, a major disadvantage is the lack of a suitable data base for identification of the materials.