A kind of high-strength high-modulus carbon fiber and its preparation method

Abstract

The invention discloses a high-strength and high-modulus carbon fiber. A preparation method of the high-strength and high-modulus carbon fiber comprises the following steps: (1) carrying out six-temperature area pre-oxidation treatment on precursor fibers by using a pre-oxidation furnace with the bulk density of the fibers as a structural performance index to obtain pre-oxidized fibers; (2) carrying out six-temperature area low-temperature carbonization treatment on the pre-oxidized fibers in a low-temperature carbonization furnace, and carrying out five-temperature area high-temperature carbonization treatment on the low-temperature carbonized fibers in a high-temperature carbonization furnace to prepare carbon fibers; and (3) carrying out ultrahigh-temperature graphitization treatment onthe carbon fibers by adopting a high-temperature graphitization furnace to prepare the high-strength and high-modulus carbon fibers. The high strength, high modulus and stable performances of the carbon fibers are achieved by matching design of the pre-oxidation temperature, the low-temperature carbonization temperature, the high-temperature carbonization temperature, the graphitization temperature, the drafting ratio and the residence time in the continuous preparation process of the fibers; and the tensile strength of the carbon fibers prepared through the method is higher than 4.2 GPa, andthe tensile modulus of the carbon fibers is higher than 500 GPa.

Description

technical field [0001] The invention relates to the technical field of carbon fiber preparation, in particular to a high-strength and high-modulus carbon fiber and a preparation method thereof. Background technique [0002] Carbon fiber has a series of advantages such as high tensile strength, high tensile modulus, small thermal expansion coefficient, corrosion resistance, and electrical conductivity, so it has been widely used in aerospace, engineering applications, civil leisure and other fields. The usual processing process of carbon fiber includes precursor fiber preparation, pre-oxidation, low-temperature carbonization and high-temperature carbonization. According to the difference in fiber performance, carbon fiber can be divided into two types: high-strength medium-mode carbon fiber and high-strength high-mode carbon fiber. On the basis of carbon fiber, it is further obtained through ultra-high temperature graphitization treatment at 2000 ° C to 3000 ° C. After graphi...

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Problems solved by technology

Due to the short pre-oxidation period, although the degree of orientation can be effectively controlled, it is difficult to ensure that the linear molecular chains of the fiber are completely converted into a heat-resistant trapezoidal structure. Therefore, the performance of the prepared carbon fiber is 3.6GPa. Tensile strength, tensile modulus 240GPa , only reaching the level of high-strength medium-mold carbon fiber

[0005] The Chinese invention patent document with the application number 201410159117.4 discloses a carbon fiber acupuncture preform with a gradient change in volume density. The composition of each layer of prefabricated body is different due to the different carbon cloth layering methods, resulting in different bulk densities, so there is a significant difference from the gradient control in the fiber preparation process of this patent

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