Their high thermal conductivity and low density make pitch-based carbo
n fibers an attractive alternative to conventional metals in heat tran
sfer applications. Already, thermal conductivities of up to 1100 W/m-d
egrees-K, about three times that of copper, have been reported. These
high conductivities are possible because of the excellent phonon condu
ction in the two-dimensional graphite layer plane. Thus, the perfectio
n of the graphitic structure to a large extent determines the thermal
conductivity of a carbon fiber. In this study, circular fibers exhibit
ing radial transverse texture and ribbon-shape fibers of linear textur
e were melt spun from a mesophase pitch precursor. After equivalent ox
idation and carbonization treatments, the fibers were characterized by
single filament tensile and electrical resistivity tests. The strong
inverse correlation of electrical resistivity and thermal conductivity
allows the use of electrical resistivity measurement as a reliable pr
edictor of thermal properties. In addition, differential scanning calo
rimetry (DSC) and wide angle X-ray diffraction techniques were used to
determine whether fiber texture can influence graphitization kinetics
. The results indicated that linear textures of the ribbon-shaped fibe
rs allow them to exhibit a lower electrical resistivity than circular
fibers of equivalent tensile moduli. The electrical resistivity of the
ribbon-shape fibers decreased with increasing aspect ratio, carboniza
tion temperature, and dwell time during carbonization. Thus, ribbon-sh
ape fibers with a linear texture should exhibit higher thermal conduct
ivities than circular fibers, and their thermal conductivities may inc
rease further with higher aspect ratios.