Preparation method for ternary polyacrylonitrile copolymer for precursor fibers of carbon fibers

Abstract

The invention relates to a preparation method for a ternary polyacrylonitrile copolymer for precursor fibers of carbon fibers. The preparation method comprises the following steps: under a nitrogen protecting condition, mixing a first monomer acrylonitrile, a second monomer acrylamide and a third monomer methacrylic acid with water; raising the temperature to 55-75 DEG C; then successively dropwise adding a chain transfer agent aqueous solution, a reducer aqueous solution and an oxidant aqueous solution; carrying out a timed reaction for 1-6 h after dropwise addition; and carrying out washing,monomer removing, filtration and drying to obtain polymer powder. The copolymer is polymerized by means of a water phase precipitation polymerization method. The polymerization reaction heat is easyto remove, the polymerization temperature is easy to control, and the relative molecular mass and distribution of the polymer are relatively uniform. The ternary polyacrylonitrile copolymer prepared by the method can improve the heat stability of the copolymer in a pre-oxidizing stage and has a certain actual application prospect.

Description

technical field [0001] The invention belongs to the field of preparation of copolymers for carbon fiber precursors, in particular to a preparation method of a ternary polyacrylonitrile copolymer for carbon fiber precursors. Background technique [0002] Carbon fiber has a series of excellent properties such as high specific strength, high specific modulus, high temperature resistance, corrosion resistance, fatigue resistance, electrical conductivity, shock absorption, heat transfer, radiation resistance, and small specific gravity. It is widely used in aerospace, military defense, and environmental protection. , medical equipment and sporting goods industries. [0003] The macromolecular chain structure of homopolymerized polyacrylonitrile is relatively regular, and its crystallinity is high. It reacts by free radical mechanism during pre-oxidation and cyclization, which is difficult to control and cannot obtain carbon fibers with good performance. When preparing polyacrylo...

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Problems solved by technology

[0003] The macromolecular chain structure of homopolymerized polyacrylonitrile is relatively regular, and the crystallinity is high. It reacts by free radical mechanism during pre-oxidation and cyclization, which is difficult to control and cannot obtain carbon fibers with good performance.

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