Pre-oxidation method for carbon fiber precursor polyacrylnitrile fiber

A technology of polyacrylonitrile fiber and precursor, applied in the direction of fiber chemical characteristics, textiles and papermaking, etc., can solve the problems of not better improving the orientation of molecular chains along the fiber axis, unfavorable cyclization process, etc., to achieve enhanced tensile strength , Improve fiber reactivity, improve the effect of orientation degree

Inactive Publication Date: 2008-09-10
DONGHUA UNIV +1
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Problems solved by technology

[0004] The disadvantage of the above method is that due to the simultaneous occurrence of cyclization in the macromolecular chain and crosslinking between the molecular chains during the pre-oxidation process, although the effect of drawing force is applied, it cannot better improve the molecular chain along the fiber axis. Orientation, and the role of oxidative crosslinking is not conducive to the cyclization process during the reaction

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  • Pre-oxidation method for carbon fiber precursor polyacrylnitrile fiber

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0024] The polyacrylonitrile fiber precursors are pre-oxidized successively through five temperature sections in the continuous pre-oxidation-low temperature carbonization furnace under normal pressure conditions:

[0025] The first and second temperature sections are the cyclization process, nitrogen gas 7 is introduced, the time is controlled at 40 minutes, the temperature of the first temperature section is 180°C, the temperature of the second temperature section is 230°C, and -5% is added in the second temperature section rigid draft;

[0026] The third, fourth, and fifth temperature sections are oxidative cross-linking processes, the air 9 is introduced, and the time is controlled at 60 minutes. The temperatures of the third, fourth, and fifth temperature sections are respectively 230°C, 250°C, and 280°C;

[0027] The sixth temperature section is the low-temperature carbonization process. Nitrogen gas 7 is passed through. There are four temperature zones, the temperatures...

Embodiment 2

[0031] The polyacrylonitrile fiber precursors are pre-oxidized successively through five temperature sections in the continuous pre-oxidation-low temperature carbonization furnace under normal pressure conditions:

[0032] The first and second temperature sections are the cyclization process, nitrogen gas is introduced, and the time is controlled at 80 minutes. The temperature in the first temperature section is 150°C, and the temperature in the second temperature section is 180°C. stretch;

[0033] The third, fourth, and fifth temperature sections are oxidative cross-linking processes. Air is introduced, and the time is controlled at 120 minutes. The temperatures of the third, fourth, and fifth temperature sections are 180°C, 230°C, and 250°C respectively;

[0034] The sixth temperature section is a low-temperature carbonization process. Nitrogen gas is introduced. There are four temperature zones. The temperatures are 400°C, 530°C, 660°C, and 800°C, and the time is controlle...

Embodiment 3

[0038] The polyacrylonitrile fiber precursors are pre-oxidized successively through five temperature sections in the continuous pre-oxidation-low temperature carbonization furnace under normal pressure conditions:

[0039] The first and second temperature sections are the cyclization process. Nitrogen gas is introduced and the time is controlled at 60 minutes. The temperature in the first temperature section is 170°C, and the temperature in the second temperature section is 210°C. stretch;

[0040] The third, fourth, and fifth temperature sections are oxidative crosslinking processes, and the air is introduced, and the time is controlled at 90 minutes. The temperatures of the third, fourth, and fifth temperature sections are 210°C, 240°C, and 270°C respectively;

[0041] The sixth temperature section is the low-temperature carbonization process. Nitrogen gas is introduced. There are four temperature zones. The temperatures are 400°C, 530°C, 660°C, and 800°C, and the time is co...

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Abstract

The invention discloses a preoxidation method for a polyacrylonitrile fiber of former body of carbon fiber. The method is, under normal pressure, to subject the polyacrylonitrile fiber precursor orderly and continuously to constant preoxidation, that is, preoxidation at five temperatures in a low temperature carbonization furnace, including a cyclization process under the protection of nitrogen at a first temperature and a second temperature with rigid drawing at the second temperature, and a oxidation crosslink process with the presence of air at a third temperature, a fourth temperature and a fifth temperature; to low temperature carbonization with nitrogen passing through the furnace at a sixth temperature; and finally to high temperature carbonization under the protection of nitrogen after entering a high temperature carbonization furnace through a tension bracket. The method has the advantages that in case of the protection of nitrogen gas, the heat treatment to fiber can improve the reactivity of the fiber, is favorable for the implement of cyclization reaction, and meanwhile in the case of the protection of nitrogen gas, the applied rigid drawing can improve the orientation degree of a molecular chain along the fiber axis, and thus polyacrylonitrile carbon fiber with higher strength and higher modulus can be obtained.

Description

technical field [0001] The invention relates to a pre-oxidation method of carbon fiber precursor polyacrylonitrile fibers, in particular to a pre-oxidation method in which an inert gas protection is used to perform cyclization in a continuous pre-oxidation-low temperature carbonization furnace, and then oxidative crosslinking is performed. Background technique [0002] Carbon fiber combines high strength, high modulus, low specific gravity, high temperature resistance, small thermal expansion coefficient, chemical corrosion resistance and excellent electrical conductivity. It is a reinforcing material for advanced composite materials. It has broad application prospects in civil fields such as transportation industry, construction industry, advanced sporting goods, and medical equipment. However, my country's carbon fiber has a very large gap with foreign carbon fiber powerhouses in terms of the quality of the raw silk and its oxidation and carbonization technology. Due to t...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): D01F9/22
Inventor 吕永根宋云鹏杨常玲秦显营周吉松邴雪飞潘鼎
Owner DONGHUA UNIV
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