The invention relates to a method for preparing a carbon
fiber precursor by
polymerization from a mixed
solvent. The method for preparing the carbon
fiber precursor by
polymerization from the mixed
solvent comprises the following steps: (1) initiating copolymerization on
acrylonitrile, 3-carboxyl-3 butylene
amide and
itaconic acid diester at the temperature of 50-80 DEG C while
dimethyl sulfoxide / deionized water or N,N-
dimethyl formamide / deionized water is taken as the
solvent and azodiisobutyronitrile is taken as an initiating agent; and (2) dissolving an
acrylonitrile polymer obtained in the step (1), defoaming, filtering, carrying out dry jet wet
spinning, drawing, oiling, compacting by
drying, drawing in
superheated steam, and carrying out
heat setting, so that the carbon
fiber precursor is obtained. The method for preparing the carbon fiber precursor by the
polymerization from the mixed solvent has the advantages that the characteristic that the
chain transfer constant of the deionized water is zero is utilized, the molecular weight of the
polymer is regulated and controlled by regulating the ratio of the deionized water to the
organic solvent, the molecular weight of the prepared
polymer is more than 1.5 times of the molecular weight of the polymer obtained by the polymerization from the traditional solvent, and the prepared carbon fiber precursor is uniform in structure, low in
fineness and high in strength; meanwhile, water is adopted for substituting part of the
organic solvent, the environment protection can be facilitated, and the production cost is effectively reduced.