A kind of method of synthesizing polyacrylonitrile copolymer

Abstract

The invention provides a method for synthesizing a polyacrylonitrile copolymer. First, a solid water-soluble initiator and a solid comonomer are added to a mixed solvent composed of an organic solvent and deionized water, and then propylene is added to the mixed solvent The nitrile main monomer and the liquid comonomer are mixed evenly to obtain a solution to be polymerized; wherein, the mass fraction of deionized water in the mixed solvent is greater than 0% and less than 10%; the solution to be polymerized is placed in a constant temperature water bath at 50°C to 70°C Magnetic stirring is carried out in the medium to generate a polymerization reaction, and a uniform transparent viscous liquid is obtained, and the uniform transparent viscous liquid is sequentially subjected to film pressing, soaking, washing, and drying to obtain a polyacrylonitrile copolymer. The polymerization solution prepared by this method is transparent, and can be directly used for spinning after only single removal and defoaming without dissolution process, especially compared to the heterogeneous polymerization process for preparing high molecular weight polyacrylonitrile copolymers. Processes such as filtration, washing, drying, and dissolution are omitted, which is beneficial to actual industrial production.

Description

technical field [0001] The invention belongs to the technical field of chemical industry, in particular to a method for synthesizing polyacrylonitrile copolymers. Background technique [0002] Carbon fiber is a high-performance material with a carbon content of over 90%. Carbon fiber has excellent properties such as high tensile strength, high elastic modulus, high temperature stability and low density. The excellent performance of carbon fiber determines its wide application in civil and military fields. Among them, polyacrylonitrile fiber is the most potential precursor for the production of carbon fiber. The carbon fiber prepared by pre-oxidation, carbonization and graphitization has excellent comprehensive performance, and the production process is relatively simple, the technology is relatively mature, and the cost is relatively low. The widest range of carbon fiber products. [0003] In order to produce high-quality and high-strength polyacrylonitrile-based carbon fi...

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Problems solved by technology

Judging from the reaction status, the former reaction is relatively moderate, and there is a transfer reaction to the small molecular chain, which is beneficial to reduce the branching of the macromolecular chain, but is not conducive to increasing the molecular weight of the polyacrylonitrile product.

Compared with the homogeneous solution polymerization system, the latter uses water as the reaction medium entirely, and there is no chain transfer reaction to the solvent, so a higher molecular weight polyacrylonitrile copolymer can be produced, but its reaction is more violent and difficult to control, and its Polymerization products need to be filtered, washed, dried, dissolved to make spinning solution, and then degassed before they can be used for spinning. The process is relatively cumbersome

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