SHEAR RATE OF MELT SPINNING FOR LARGE DIAMETER MESOPHASE PITCH FILAMENT

Rheological characteristic and shear rate of mesophase pitch in microhole passage of spinneret during melt spinning for preparation of large diameter mesophase pitch filament were investigated. It was found that shear rate increased with increase of melt spinning temperature and extrusion flow. The large diameter mesophase pitch carbon monofiber in uniform size was obtained by controlling the matching of extrusion flow and drawing rate. The difference of shear rate between two mesophase pitches, and the difference of dispersion coefficient between two kinds of fibers derived from the two mesophase pitches can be contributed to the different molecular structure of mesophase pitch prepared under different pressure.