Method suitable for carrying out consolidation forming on polyacrylonitrile carbon fiber precursor by dry-wet method

Abstract

The invention relates to a method suitable for carrying out consolidation forming on a polyacrylonitrile carbon fiber precursor by a dry-wet method. The method comprises the following preparation steps: in a low-temperature low-concentration coagulating bath with a consolidation temperature of 20 DEG C below zero to 25 DEG C and mass concentration of 5 to 40 percent, enabling spinning solution to pass through a spinneret plate and jetting the spinning solution by an air layer so as to enable the spinning solution to enter the coagulating bath, wherein residence time in the coagulating bath is 2 to 10s; rapidly quenching the surface of stock solution to generate a hard film; by the hard film and the conditions of low temperature, low concentration and the like, slowing down a double diffusion rate, improving the orientation degree of nascent fibers by the hard film to realize homogenizing of consolidation forming and avoid a skin-core structure so as to obtain the nascent fibers with pre-draft times of 2.3 to 4.0 times, wherein the nascent fibers have orientation degree of 65 to 70 percent. The protofilament prepared by the method disclosed by the invention has high homogeneity; high-quality protofilaments and carbon filaments can be obtained; moreover, in the dry-wet technology, the method has strong universality and can be popularized and used in the dry-wet production.

Description

technical field

[0001] The invention relates to the technical field of preparation of polyacrylonitrile carbon fiber precursors, in particular to a method suitable for low-temperature and low-concentration homogeneous coagulation molding of dry-wet method polyacrylonitrile carbon fiber precursors. Background technique

[0002] Polyacrylonitrile-based carbon fiber is the most promising precursor for the production of high-performance carbon fiber. The carbon fiber obtained through the pre-oxidation and carbonization process using polyacrylonitrile precursor fiber as the starting material has the best comprehensive performance. In the process of preparing polyacrylonitrile precursor fiber, coagulation molding is the key link of production, so the molding quality of the primary fiber directly affects the comprehensive performance of the precursor fiber and carbon fiber. In wet spinning, coagulation and forming mainly rely on double diffusion as the forming power, so that the sp...