The invention discloses a method for preparing a high-strength
polyacrylonitrile-based carbon
fiber precursor. The method comprises the steps of: using azodiisobutyronitrile to trigger
acrylonitrile and a
comonomer to perform homogeneous
solution polymerization in
dimethyl sulfoxide to obtain
spinning solution, and controlling the temperature of the
spinning solution to be between 40 and 70 DEG C and the
solid content to be between 18 and 24 percent; performing
monomer removal on the
spinning solution under the pressure of between -60 and -78kPa, and performing deaeration treatment under the pressure of between -78 and -97kPa; then extruding the spinning solution into a spin duct in a coagulation bath with a temperature of between 35 and 65 DEG C and a
dimethyl sulfoxide concentration of between 50 and 70 percent for molding through a spinneret, and obtaining PAN-based as-spun
fiber through 45 to 75 percent of minus stretch in the coagulation bath; then molding and stretching through a secondary coagulation bath, a third coagulation bath, a fourth coagulation bath and a fifth coagulation bath; and obtaining the high-strength
polyacrylonitrile-based carbon
fiber precursor through
solvent removal by water scrubbing, hot water stretch, oiling,
drying and densification, steam stretch, and hot air setting. The tensile strength of the high-strength
polyacrylonitrile-based carbon fiber precursor reaches 10.2cN / dtex.