An Evaluation of Naphthalene-Based Mesophase as a Carbon Fiber Precursor

Abstract

Naphthalene-based mesophase, supplied by Mitsubishi Gas Chemical Co., Inc., (under the commercial name “AR” mesophase) and a heat-soaked mesophase pitch were melt-spun into fiberform using a pilot-scale extruder. The oxidation conditions of the as-spun fibersformed from each mesophase were optimized (based on tensile strength), and all fibers were graphitized at 2400°C. The naphthalene-based mesophase was found to be more spinnable, despite the fact thatits viscosity was more temperature-dependent than that of the heat-soaked mesophase. Also, fibers formed from the naphthalene-based mesophase were found to stabilize more rapidly than those formed from the heatsoaked mesophase. After carbonization, the naphthalene-based mesophase fibers exhibited much higher tensile strengths and moduli than equal-sized fibers produced from heat-soaked mesophase. The naphthalene-based mesophase fibers also exhibited lower electrical resistivities. Wide angle X-ray diffraction showed that the naphthalene-based mesophase fibers developed a smaller average interplanar spacing of the graphite basal planes and a larger average crystallite size than the heat-soaked mesophase pitch-based fibers.