Preparation method of graphene fiber with high graphite crystallinity

A high-crystallinity, carbonaceous fiber technology, applied in the field of nanomaterials, can solve the problems of graphene with low degree of oxidation and low structural defects, unfavorable molding processing, and difficulty in orientation, so as to reduce internal defects in fibers and reduce production costs. , reduce the effect of performance improvement

Active Publication Date: 2022-05-13
ZHEJIANG UNIV
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Problems solved by technology

The existing graphene / polymer composite materials mainly have the following problems: First, the graphene sheet diameter is small, because the raw materials for the preparation of graphene or graphene oxide with small sheet diameter are easier to obtain, so most graphene / polymer composites The size of graphene sheets in the compound composites is less than 10 microns, which cannot give full play to the advantages of graphene as a two-dimensional topological geometric planar structure.
The second is that graphene is disorderly arranged in the polymer and it is difficult to orientate. Due to the small size of the graphene used, it is difficult for graphene to form a liquid crystal phase in the dispersion and polymer solution.
Therefore, the fluidity of the composite solution will be greatly weakened, which is not conducive to the subsequent molding process
Combining one and two points, graphene cannot form a continuous network in the polymer system, and it is a composite structure of sea-island phases, and the interlayer confinement of graphene is limited, so the molecular arrangement of the polymer body is highly disordered, and the crystallization region The degree of crystallinity is low, and the polymer molecular chain needs to be improved through subsequent processes such as multiple stretches, resulting in complicated processes and increased costs
In addition, the third is that the low degree of oxidation and structural defects of graphene are not high. Since most of the existing graphene is added to the polymer system as a physical filler, the oxygen-containing functional groups and structural defects of graphene itself are ignored as chemical groups. chemical catalysis
Therefore, the chemical properties of graphene itself have not been fully utilized

Method used

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  • Preparation method of graphene fiber with high graphite crystallinity
  • Preparation method of graphene fiber with high graphite crystallinity
  • Preparation method of graphene fiber with high graphite crystallinity

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Experimental program
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Effect test

Embodiment 1

[0026] The present embodiment adopts one-dimensional linear polymer polyacrylonitrile (its residual carbon rate is 30%, aromatization index is 0.8) to prepare carbon fiber, has studied the parameter (see table 1) of the two-dimensional lamellar seed crystal used for induction The impact on its performance is as follows:

[0027] (1) Evenly disperse polyacrylonitrile in pure DMF solution, add graphene oxide to form a spinning solution, and the solid content of the system is 5%.

[0028] (2) Extrude the liquid crystal composite spinning solution into a coagulation bath of pure ethyl acetate, and obtain high crystallinity composite precursor fibers through a wet liquid crystal spinning process. Maintain a proper draft force of 5N during the spinning process.

[0029] (3) Place the raw silk in a tube furnace, heat it up to 2000°C for 3 hours, and treat it with an air pressure of 10 MPa.

[0030] Table 1

[0031]

[0032] Through the wide-angle X-ray diffraction test, the cry...

Embodiment 2

[0042] In this embodiment, different one-dimensional linear polymers (with different carbon residue rates and aromatization indices) are used to prepare carbon fibers, as shown in Table 3, as follows:

[0043] (1) Uniformly disperse the one-dimensional linear polymer in pure DMSO solution, add graphene oxide to form a spinning solution, and the solid content of the system is 10%. The size of graphene oxide is 45±20 microns, and the carbon-to-oxygen ratio is 2.5; the ratio of the carbon content of the two-dimensional flake crystal seed to the carbon content of the polymer is controlled at 0.76±0.02; the solid content of the mixed solution is 5 mg / g.

[0044] (2) Extrude the liquid crystal composite spinning solution into a coagulation bath of pure ethyl acetate, and obtain high crystallinity composite precursor fibers through a wet liquid crystal spinning process.

[0045] (3) Put the raw silk in a tube furnace, heat it up to 2000° C. or more, and heat it with an air pressure o...

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Abstract

The invention discloses a preparation method of a graphene fiber with high graphite crystallinity, which mainly adopts a wet spinning mode to perform liquid-phase composite assembly on graphene oxide and other polymer materials, and two-dimensional graphene oxide sheets perform'template orientation 'on polymer molecules to obtain the graphene fiber with high graphite crystallinity. The polymer molecules are directionally crystallized on the two-dimensional graphene oxide sheet, so that the composite precursor with high orientation degree and crystallinity is prepared. The preparation method comprises the following steps: performing high-temperature treatment on a graphene sheet with a two-dimensional topological structure, performing catalytic pyrolysis on molecules through an induced graphitization effect, and directionally generating a graphene-like carbon layer by taking a single-layer graphene sheet as a template, so that the stacking behavior of the graphene sheet layer is promoted, and the composite carbon fiber with an optimal graphite crystal structure is prepared. The graphene fiber material prepared by the method has the characteristics of low cost, high crystallinity and high performance, and can be applied to the field of light high-strength structural materials. The invention relates to a high-crystallinity graphene fiber material with a two-dimensional induction effect and a preparation method of the high-crystallinity graphene fiber material.

Description

technical field [0001] The invention relates to the field of nanometer materials, in particular to a method for preparing graphene fibers with high graphite crystallinity. Background technique [0002] One-dimensional linear polymers are cheap and easy to obtain. In the industrial production of carbon fibers, they are mainly obtained through high-temperature carbonization and crystallization of one-dimensional linear polymer precursors. After the commercial polyacrylonitrile carbon fiber is carbonized at 1300 degrees, its mechanical strength is high, but the size of the internal graphite crystal region is small and the arrangement is disordered, resulting in poor electrical and thermal conductivity, and the thermal conductivity is 60W / mK. Even after the high-temperature graphitization treatment at 2800 degrees, the size of the graphite crystal region is slightly increased, but it is still unable to generate large-sized graphite crystal regions, and the highest thermal conduc...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): D01F9/22D01F9/24D01F9/145D01F9/17D01F1/09D01F1/10C01B32/184
CPCD01F9/22D01F9/24D01F9/145D01F9/17D01F1/09D01F1/10C01B32/184
Inventor 高超明鑫许震刘英军
Owner ZHEJIANG UNIV
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