Method of preparing carbon fibers through crosslinked reaction of boron trichloride and polyacrylonitrile precursors

Abstract

The invention relates to a method of preparing carbon fibers through crosslinked reaction of boron trichloride and polyacrylonitrile precursors. In the method, the boron-nitrogen bonds are formed by the reaction of the boron trichloride and unsaturated functional groups such as cyan in polyacrylonitrile precursors, the boron is uniformly introduced in the fiber, the chemical crosslinking of the polyacrylonitrile precursors is also realized, the crosslinked precursors are carbonized under the nitrogen protection and graphitized under the argon protection, and the original air preoxidation process is replaced. Compared with unmodified fiber obtained through air preoxidation, the release of the highly toxic gas such as hydrogen cyanide in the pyrolysis tail gas is greatly reduced, and the modulus of the carbon fiber is obviously improved. In the method, the process steps are not increased, the uniform chemical modification of boron is realized, the boron introduced by bonding can keep to the graphitization stage, no influence can be caused on the graphitization process, the production cost is low, and the industrialized production is convenient.

Description

technical field [0001] The invention relates to a method for preparing carbon fibers, in particular to a method for preparing carbon fibers by using polyacrylonitrile precursors. Background technique [0002] Carbon fiber combines high strength, high modulus, low density, high temperature resistance, small thermal expansion coefficient, chemical corrosion resistance, electrical conductivity and other excellent properties. Transportation industry, construction industry, advanced sporting goods, medical equipment and other civil fields have been widely used and have broad development prospects. Among the three types of industrial carbon fibers divided by raw materials, polyacrylonitrile carbon fiber has the highest mechanical properties, the most widely used, the largest consumption, and the fastest development, and is still in the process of continuous research and development and improvement. [0003] Due to the limitations of the production of raw silk and technology, in t...

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Problems solved by technology

Polyacrylonitrile powder and BCl by Kawaguchi et al. 3 Reaction at 400°C followed by heat treatment at 1000°C produced a black powdery BC 3 N [J Chem Soc Chem Commun, 1993, (14), 1133-1134], but failed to produce high-performance carbon fibers