Micro-Raman spectroscopic measurements on carbon fibers

High-module pitch-based carbon fibers of about 10 mu m thickness (produced in Russia) with a heat-treatment temperature of 3000 degrees C and their intercalated compounds have been investigated by Raman spectroscopy with an optical microscope. The first-order and the second-order Raman spectra of pristine fibers did not differ significantly from those of highly oriented pyrolytic graphite samples with a high level of order. The resistivity of the fibers at room temperature was decreased by a factor 7 as a result of bromination, The bromine-intercalated fibers were stable in air up to 100 degrees C. Micro-Raman spectroscopy was used for control of the intercalation process and determination of the degree of order in pristine and intercalated carbon fibers with the aim of optimizing the intercalation time for these types of fibers.