Polyacrylonitrile carbon fiber prepared by using waste polyacrylonitrile fiber and preparation method thereof

Abstract

The invention discloses a polyacrylonitrile carbon fiber prepared by using waste polyacrylonitrile fiber and a preparation method thereof, and the method comprises the following steps: (1) dehydratingthe waste polyacrylonitrile fiber to obtain a completely dehydrated waste polyacrylonitrile fiber; (2)chopping the fully dehydrated waste polyacrylonitrile fiber, mixing with a solvent, swelling at room temperature, stirring at a high temperature to prepare a polymer solution, filtering, and defoaming to obtain a spinning solution; (3) spinning the spinning solution to obtain a polyacrylonitrileraw silk; (4)pre-oxidizing and carbonizing the polyacrylonitrile raw silk to obtain a polyacrylonitrile carbon fiber. The method is adopted to obtain a completely dehydrated waste silk, a spinning solution of carbon fiber raw silk having a polyacrylonitrile mass concentration of 19-22% is prepared, and the raw silk prepared by the spinning solution is pre-oxidized and carbonized to finally obtaina polyacrylonitrile carbon fiber with linear density of 38 to 66 g/km, tensile strength of 3.8 to 5.6 GPa, and tensile modulus of 230 to 300 GPa.

Description

technical field [0001] The invention belongs to the technical field of carbon fibers, in particular, the invention relates to polyacrylonitrile carbon fibers prepared from waste polyacrylonitrile fibers and a preparation method thereof. Background technique [0002] Polyacrylonitrile (PAN) carbon fiber is the most important reinforcing material in advanced composite materials. Due to a series of excellent properties such as high specific strength and high specific modulus, it has been successfully used in aviation, aerospace, automobiles, machinery, chemicals, sports, In medical and other industries, countries all over the world have paid great attention to the development of polyacrylonitrile carbon fiber. [0003] After more than ten years of development, dozens of polyacrylonitrile carbon fiber research and production lines have been built in China. In a carbon fiber factory with a raw silk production line, due to various reasons, a large amount of PAN fiber waste is pro...

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Problems solved by technology

The diameter of phase change fibers is usually greater than 100 microns. The milky white spinning solution obtained by this method can be used to prepare phase change fibers, but it is not suitable for the preparation of polyacrylonitrile carbon fiber precursors with a diameter of only a dozen microns, and the production of carbon fiber precursors. The spinning solution must be a polyacrylonitrile solution. In order to prevent clogging the spinneret aperture and avoid insoluble impurities in the fiber, the polyacrylonitrile spinning solution must pass through a micron-level filtration system, and the milky white spinning solution is difficult to pass through.

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