PROPERTIES OF GRAPHITIZED CARBON FIBER-HALOGEN RESIDUE COMPOUNDS

Br//2 or ICl residue compound formation in TP 4104B and GY-70 fibers increases electrical conductivity 3-5 times. It also decreases the tensile strength of GY-70 by increasing their cross-sectional area. In contrast, tensile strength of TP 4104B remains unchanged on Br//2 or ICl residue compound formation. The TP 4104B/Br//2 residue compound increases resistance by only 5-10% when heated to 400 degree C in air; the ICl residue compounds of both fibers are unstable above 150 degree C. The temperature coefficient of resistivity of the unintercalated fibers (in the range 2-673 K) is attributed to a temperature dependent variation in the number of current carriers in the intercrystalline regions of the fibers. The magnetoresistance from 2-200 K is attributed to a large resistance increase within the graphite crystallites. Both are consistent with a metallic-like electron structure. The preparation of bromine residue compounds of individual TP 4104B fibers that had different bromine concentrations was not successful.