Preparation method of wet-process high-strength polyacrylonitrile-based carbon fiber

The invention relates to a preparation method of a wet-process high-strength polyacrylonitrile-based carbon fiber. The preparation method sequentially comprises the following steps: step1. preparing a PAN (Polyacrylonitrile) copolymer; step 2. removing monomers and removing foams; step 3. filtering and metering; step 4. carrying out consolidation forming; step 5. carrying out primary-drafting, washing, drying and compacting, re-drafting and thermally setting to prepare precursor fibers; and step 6. carrying out pre-oxidizing, low-temperature carbonizing and high-temperature carbonizing to finally obtain carbon fibers, wherein the coagulating bath system used in the step 4 consists of a good solvent of polyacrylonitrile, precipitator water and water soluble low carbon fatty amine. According to the preparation method provided by the invention, contact between the polymer and the precipitator water is alleviated by means of the appetency of the low carbon fatty amine and the polymer component to accelerate the solution trickle to precipitate with a slow speed phase so as to effectively reduce hole defects and skin cores of the precursor fibers in the conventional wet-process solidification forming process, so that the shape structure of the precursor fibers is improved, devitrification and non-uniformity of the precursor fibers are reduced, radial solidification and dispersion uniformity of the solution trickle are expanded and strands far from the bath are compact and transparent.