A kind of high tensile modulus graphite fiber and preparation method thereof

Abstract

The invention discloses a high-tensile-modulus graphite fiber and a preparation method thereof. The preparation method comprises the following steps: thermally treating precursor fibers to obtain thermally crosslinked fibers, selecting a thermally crosslinked fiber having a cyclization degree ranging between 55 percent and 100 percent by taking the cyclization degree as a structural control indexof the thermally crosslinked fiber, and enabling the selected fiber to continuously pass through a seven-temperature-area low-temperature carbonization furnace, a three-temperature-area high-temperature carbonization furnace and a single-temperature-area graphitization furnace in sequence to prepare the high-tensile-modulus graphite fiber. In a continuous preparation process of the fiber, treatment processes of low-temperature carbonization, high-temperature carbonization and graphitization are reasonably designed by controlling the cyclization degree of the raw material fiber, so as to achieve the high-modulus performance of a carbon fiber. The tensile modulus of the carbon fiber, prepared by the method disclosed by the invention, is more than 500 GPa.

Description

technical field [0001] The invention relates to the technical field of carbon fiber preparation, in particular to a high tensile modulus graphite fiber and a preparation method thereof. Background technique [0002] Graphite fiber is a high-modulus carbon fiber with a small thermal expansion coefficient and good thermal conductivity. It is mainly used in parts that require high rigidity and small thermal deformation, such as solar wings, antennas, and space optical remote sensor structures. Compared with medium modulus or general-purpose carbon fibers, graphite fibers have a higher carbon content in chemical composition and exhibit increased graphite crystallite size in microstructure. [0003] Graphite microcrystalline structure is the structural basis for carbon fiber to achieve high modulus. From the perspective of fiber structure evolution, thermally crosslinked fibers already have a ring structure similar to graphite structure. After further high temperature treatment, ...

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Problems solved by technology

This invention only discloses that the pre-oxidation process is beneficial to the cyclization reaction, and does not select fibers with a certain degree of cyclization, nor does it establish the effect of the fiber ring structure on the modulus of carbon fibers, so it is the same as the cyclization degree in the fiber preparation process of the present application. Significant difference in choice

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