Coarse-denier high-strength medium-mode polyacrylonitrile-based carbon fiber and preparation method thereof

Abstract

The invention relates to the field of fiber technology, in particular to a coarse-denier high-strength medium-mode polyacrylonitrile-based carbon fiber and a preparation method thereof. The preparation method of the polyacrylonitrile-based carbon fiber comprises the following steps: S1: preparing the polyacrylonitrile spinning stock solution with polyacrylonitrile powder and dimethyl sulfoxide; S2: passing the polyacrylonitrile spinning stock solution through the spinneret hole Extrude, pass through the air layer, and enter the non-aqueous solvent gel bath with a temperature of 0℃~-50℃ for positive drawing to obtain the as-spun fibers; S3: extract the as-spun fibers, wash them with water, then heat-draw, dry and densify, and After oiling, the raw silk is prepared; S4: pre-oxidize the obtained raw silk, carbonize at a low temperature of 500°C to 800°C, carbonize at a high temperature of 1100°C to 1600°C, electrochemically treat, wash with water, sizing and dry winding. Through the present invention, a coarse denier, high-strength, medium-mode carbon fiber based on dry-jet gel spinning is obtained, which is suitable for the application requirements of composite materials in aviation, aerospace and other fields.

Description

technical field

[0001] The invention relates to the field of fiber technology, in particular to a coarse-denier high-strength medium-mode polyacrylonitrile-based carbon fiber and a preparation method thereof. Background technique

[0002] Polyacrylonitrile is currently the only and most widely used precursor for preparing high-performance carbon fibers. Using polyacrylonitrile (PAN) with one or more comonomers, different specifications of carbon fibers can be prepared by dissolution, spinning, thermal oxidation, carbonization, and graphitization. Due to its low density and high mechanical properties, carbon fiber is widely used in aviation, aerospace, industry, sports equipment and other fields, and is an important structural reinforcement material.

[0003] At present, the T300 and T700 grade coarse denier (7μm diameter) carbon fiber products on the market belong to the series of medium strength (≤5GPa) and low modulus (≤260GPa), while the T800 grade carbon fiber belongs t...

Examples

preparation example Construction

[0037] A kind of preparation method of polyacrylonitrile-based carbon fiber, such as figure 1 shown, including the following steps:

[0038] S1: mixing polyacrylonitrile powder with an organic solvent to prepare a polyacrylonitrile spinning stock solution;

[0039] S2: extruding the polyacrylonitrile spinning stock solution through the spinneret, entering a non-aqueous solvent gel bath with a temperature of 0°C to -50°C, and then being drawn to obtain primary fibers;

[0040] S3: After the primary fiber is extracted, washed with water, hot-drawn at 40-95°C, dried and densified, and oiled, the raw fiber is prepared;

[0041] S4: pre-oxidizing the obtained raw silk, carbonizing at 500° C. to 800° C., carbonizing at 1100° C. to 1600° C., electrochemical treatment, washing with water, sizing, and drying and winding.

Embodiment 1

[0043] (1) Preparation of polyacrylonitrile-methyl acrylate PAN-MA powder:

[0044] Acrylonitrile (AN) is used as raw material, methyl acrylate (MA) is added, the mass ratio is 96:4, 20wt% of the total mass percentage is added to the aqueous polymerization reactor, and 0.3mol% of the water system is used to initiate oxidation-reduction. The agent (ammonium persulfate-ammonium bisulfite) was polymerized at a constant temperature of 40 °C for 6 hours, and the formed slurry was filtered, washed with water, and dried with hot air at 90 degrees to a moisture content of less than 5wt% to obtain polyacrylonitrile-methyl acrylate PAN. -MA powder.

[0045] (2) Preparation of polyacrylonitrile spinning stock solution:

[0046] The polyacrylonitrile-methyl acrylate PAN-MA (3.4wt%) powder with a molecular weight of 150,000 was mechanically ground into a powder of less than 100 mesh, mixed with DMSO at 19°C and mechanically stirred (rotation speed 800rpm) to prepare a solid content of 20....

Embodiment 2

[0058] This embodiment is basically the same as Embodiment 1, except that:

[0059] (1) Preparation of polyacrylonitrile-itaconic acid PAN-IA powder

[0060] Acrylonitrile (AN) was used as raw material, and itaconic acid (IA) was added in a mass ratio of 98:2.

[0061] (2) Preparation of polyacrylonitrile spinning stock solution:

[0062] The polyacrylonitrile-itaconic acid PAN-IA (1.8wt%) powder with a molecular weight of 150,000 was mixed with DMF, and a dispersion liquid with a solid content of 24wt% was prepared by the same method as in Example 1. The subsequent steps and examples In the same way as 1, a polyacrylonitrile PAN spinning stock solution was obtained, and the viscosity of the polyacrylonitrile PAN spinning stock solution at room temperature was 112 Pa.s.

[0063] (3) Preparation of primary fibers

[0064] During the spinning process, the temperature of the polyacrylonitrile PAN spinning stock solution was kept at 50 °C, transferred to a metering pump, extrud...

technical field

[0001] The invention relates to the field of fiber technology, in particular to a coarse-denier high-strength medium-mode polyacrylonitrile-based carbon fiber and a preparation method thereof. Background technique

[0002] Polyacrylonitrile is currently the only and most widely used precursor for preparing high-performance carbon fibers. Using polyacrylonitrile (PAN) with one or more comonomers, different specifications of carbon fibers can be prepared by dissolution, spinning, thermal oxidation, carbonization, and graphitization. Due to its low density and high mechanical properties, carbon fiber is widely used in aviation, aerospace, industry, sports equipment and other fields, and is an important structural reinforcement material.

[0003] At present, the T300 and T700 grade coarse denier (7μm diameter) carbon fiber products on the market belong to the series of medium strength (≤5GPa) and low modulus (≤260GPa), while the T800 grade carbon fiber belongs t...

Examples

preparation example Construction

[0037] A kind of preparation method of polyacrylonitrile-based carbon fiber, such as figure 1 shown, including the following steps:

[0038] S1: mixing polyacrylonitrile powder with an organic solvent to prepare a polyacrylonitrile spinning stock solution;

[0039] S2: extruding the polyacrylonitrile spinning stock solution through the spinneret, entering a non-aqueous solvent gel bath with a temperature of 0°C to -50°C, and then being drawn to obtain primary fibers;

[0040] S3: After the primary fiber is extracted, washed with water, hot-drawn at 40-95°C, dried and densified, and oiled, the raw fiber is prepared;

[0041] S4: pre-oxidizing the obtained raw silk, carbonizing at 500° C. to 800° C., carbonizing at 1100° C. to 1600° C., electrochemical treatment, washing with water, sizing, and drying and winding.

Embodiment 1

[0043] (1) Preparation of polyacrylonitrile-methyl acrylate PAN-MA powder:

[0044] Acrylonitrile (AN) is used as raw material, methyl acrylate (MA) is added, the mass ratio is 96:4, 20wt% of the total mass percentage is added to the aqueous polymerization reactor, and 0.3mol% of the water system is used to initiate oxidation-reduction. The agent (ammonium persulfate-ammonium bisulfite) was polymerized at a constant temperature of 40 °C for 6 hours, and the formed slurry was filtered, washed with water, and dried with hot air at 90 degrees to a moisture content of less than 5wt% to obtain polyacrylonitrile-methyl acrylate PAN. -MA powder.

[0045] (2) Preparation of polyacrylonitrile spinning stock solution:

[0046] The polyacrylonitrile-methyl acrylate PAN-MA (3.4wt%) powder with a molecular weight of 150,000 was mechanically ground into a powder of less than 100 mesh, mixed with DMSO at 19°C and mechanically stirred (rotation speed 800rpm) to prepare a solid content of 20....

Embodiment 2

[0058] This embodiment is basically the same as Embodiment 1, except that:

[0059] (1) Preparation of polyacrylonitrile-itaconic acid PAN-IA powder

[0060] Acrylonitrile (AN) was used as raw material, and itaconic acid (IA) was added in a mass ratio of 98:2.

[0061] (2) Preparation of polyacrylonitrile spinning stock solution:

[0062] The polyacrylonitrile-itaconic acid PAN-IA (1.8wt%) powder with a molecular weight of 150,000 was mixed with DMF, and a dispersion liquid with a solid content of 24wt% was prepared by the same method as in Example 1. The subsequent steps and examples In the same way as 1, a polyacrylonitrile PAN spinning stock solution was obtained, and the viscosity of the polyacrylonitrile PAN spinning stock solution at room temperature was 112 Pa.s.

[0063] (3) Preparation of primary fibers

[0064] During the spinning process, the temperature of the polyacrylonitrile PAN spinning stock solution was kept at 50 °C, transferred to a metering pump, extrud...

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