Preparing method of polyacrylonitrile (PAN) used for carbon fiber

Abstract

A preparing method of polyacrylonitrile (PAN) used for carbon fiber is provided. The preparing method adopts a water-phase precipitation polymerization reaction, adopts water-soluble ammonium sulfate-sodium bisulfite-ferrous sulfate as an oxidation-reduction initiation system, adopts a monoester of itaconic acid as a bifunctional copolymerization monomer, and adopts sulfuric acid as a pH conditioner. The bifunctional copolymerization monomer and acrylonitrile are subjected to a precipitation polymerization reaction in a water phase, then the reaction system is alkalified by aqueous ammonia, and after separation, washing and drying, PAN powder is obtained. The preparing method is low in cost, short in polymerization time, and high in production efficiency, and the prepared polyacrylonitrile is high in purity and good in spinnability and preoxidation controllability, so that the preparing method is suitable for large-scale production of carbon fiber precursor and facilitates reduction of the production cost of carbon fiber.

Description

technical field [0001] The invention relates to the technical field of carbon fiber preparation, in particular to a preparation method of polyacrylonitrile (PAN) polymer for carbon fiber. Background technique [0002] Carbon fiber is a well-known high-tech fiber material with a series of excellent properties such as high specific strength, high specific modulus, high temperature resistance, corrosion resistance, good electrical and thermal conductivity, and small thermal expansion coefficient. Advanced composite materials reinforced with carbon fiber have played an irreplaceable role in key components of military and civil aircraft, as well as strategic missiles and launch vehicles. In recent years, with the increasingly prominent problems of energy shortage and environmental pollution, the lightweight automobile technology using carbon fiber composite materials has attracted more and more attention. Using carbon fiber reinforced resin-based composite materials instead of s...

AI Technical Summary

Problems solved by technology

However, in the ternary copolymerization system, due to the difference in reactivity between acrylonitrile and the second and third comonomers, it often leads to uneven distribution of comonomers on the PAN molecular chain, which affects its spinnability and prepolymerization. Improvement effect of oxidation controllability

[0006] In addition, inorganic initiators are often used as polymerization initiators in aqueous phase polymerization, but there are two problems with the commonly used inorganic initiators at present (1) high cost; (2) other metal elements are contained in the initiator, and these metal elements are The elements exist in the PAN polymer in the form of ions, which will have adverse effects on the thermal stability of the PAN polymer, the spinnability during spinning and fiber production, and the physical properties of the fiber.

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