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A preparation method of polyacrylonitrile-based high-strength and high-modulus carbon fiber

A high-modulus carbon fiber, polyacrylonitrile-based technology, applied in the direction of fiber chemical characteristics, textiles and papermaking, can solve the problems of rising, changing at the same time, and not being able to match the relevant models of T-series carbon fibers

Active Publication Date: 2020-10-27
BEIJING UNIV OF CHEM TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Stretching is an effective method to improve the preferred orientation of carbon crystallites in carbon fibers. The adjustment of high-temperature graphitization temperature and tension to change the orientation of carbon crystallites in graphite fibers has become a research hotspot for many scholars. Little research has been done on the effects of plasticity
At the same time, in the research process of T series high-strength carbon fibers, some studies believe that 1500°C is the optimal carbonization temperature point of high-strength carbon fibers. Increasing the high-temperature carbonization treatment temperature will cause the simultaneous changes in the strength and modulus of carbon fiber mechanical properties, which cannot match the T series. Therefore, when preparing high-temperature carbonized fibers, scholars hardly try to make higher carbonization temperatures.

Method used

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  • A preparation method of polyacrylonitrile-based high-strength and high-modulus carbon fiber
  • A preparation method of polyacrylonitrile-based high-strength and high-modulus carbon fiber
  • A preparation method of polyacrylonitrile-based high-strength and high-modulus carbon fiber

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0032] (1) Pre-oxidation of PAN precursor

[0033] The 1K low-denier laboratory wet-process self-made PAN precursor was pre-oxidized in an air atmosphere using a gradient temperature rise method. The pre-oxidation start temperature was 210°C, the pre-oxidation end temperature was 255°C, and the pre-oxidation time was 45 minutes.

[0034] (2) Low temperature carbonization

[0035] Put the obtained pre-oxidized fiber into a low-temperature carbonization furnace for low-temperature carbonization treatment, using nitrogen as a protective gas, and the oxygen content in nitrogen is 1.0ppm. The low-temperature carbonization temperature is 700°C, and the low-carbon carbonization time is 3 minutes.

[0036] (3) High temperature carbonization

[0037] Put the obtained low-temperature carbonized fiber into a high-temperature carbonization furnace for high-temperature carbonization treatment, using high-purity nitrogen as a protective gas, and the oxygen content in nitrogen is 1.0ppm. Th...

Embodiment 2

[0042] (1) Pre-oxidation of PAN precursor

[0043] The Weihai extension 6K wet-process PAN precursor was pre-oxidized in an air atmosphere using a gradient heating method. The pre-oxidation starting temperature was 200°C, the pre-oxidation termination temperature was 260°C, and the pre-oxidation time was 45 minutes.

[0044] (2) Low temperature carbonization

[0045] The obtained pre-oxidized fiber enters a low-temperature carbonization furnace for low-temperature carbonization treatment, using nitrogen as a protective gas, and the oxygen content in the nitrogen is 1.0 ppm. The low-temperature carbonization temperature is 750°C, and the low-carbon carbonization time is 3 minutes.

[0046] (3) High temperature carbonization

[0047] The fibers enter the high-temperature carbonization furnace after low-temperature carbonization, and high-purity nitrogen is used as the protective gas, and the oxygen content in nitrogen is 1.0ppm. The carbonization temperature is 1600°C, the ca...

Embodiment 3

[0051] (1) Pre-oxidation of PAN precursor, (2) Low temperature carbonization

[0052] Same as Example 2

[0053] (3) High temperature carbonization

[0054] The obtained low-temperature carbonized fiber enters a high-temperature carbonization furnace for high-temperature carbonization, using high-purity nitrogen as a protective gas, and the oxygen content in the nitrogen is 1.0 ppm. The high-temperature carbonization temperature is 1650° C., the residence time is 2 minutes, and a relative stretching ratio of 96.8% is applied to both ends of the fiber during high-temperature carbonization treatment. The orientation angle of carbon crystallites in the obtained high-temperature carbonized fiber is 17.03°.

[0055] (4) High temperature graphitization

[0056] The obtained high-temperature carbonized fiber enters a graphitization furnace for high-temperature graphitization treatment, and nitrogen gas is used as a protective gas, and the oxygen content in the nitrogen gas is 1.0 ...

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Abstract

The invention relates to a preparation method of polyacrylonitrile-based high-strength high-modulus carbon fibers. After polyacrylonitrile (PAN) precursors are subjected to conventional pre-oxidationand low-temperature carbonization, the carbon crystalline orientation can be effectively controlled by increasing the high-temperature carbonization temperature and matching a certain stretching, or increasing the high-temperature carbonization stretching ratio to obtain high-temperature carbonized fibers with an orientation angle of being not greater than 17.5 degrees, and high-temperature graphitization hot drawing treatment is conducted at a relatively low temperature to obtain the high-strength high-modulus carbon fibers with tensile strength of 3.8-5.0 GPa and tensile modulus of 500-600 GPa. The preparation method reduces the requirements on equipment for high-temperature graphitization, which is beneficial to energy saving and cost reduction, and the operation is simple and easy.

Description

technical field [0001] The invention relates to a method for preparing polyacrylonitrile-based high-strength and high-modulus carbon fibers Background technique [0002] Polyacrylonitrile-based carbon fibers are widely used in aerospace, national defense, building reinforcement, petrochemical and Leisure sports and other fields. With the continuous progress and development of the application technology of carbon fiber composite materials, high-strength and high-model carbon fiber has become an indispensable key material in the special field of aerospace because of its characteristics of high strength and high modulus. [0003] High-modulus carbon fibers are usually prepared by high-temperature graphitization of high-strength carbon fibers. After high-temperature treatment of polyacrylonitrile (PAN)-based carbon fibers at a temperature higher than 2000 ° C, carbon content of more than 99% and carbon crystallites in the fibers can be obtained. High modulus carbon fiber with ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): D01F9/22
CPCD01F9/225
Inventor 王宇赵振文高爱君李常清徐樑华童元建曹维宇
Owner BEIJING UNIV OF CHEM TECH