A method for preparing graphene oxide fibers

Abstract

The present application is based on the fact that ammonium salt is easy to decompose into ammonium ion, which can form ionic crosslinking with oxygen-containing groups on the graphene oxide layer, providing strong interlayer force, so that it can withstand large tensile load to make the graphene oxide layer arrange flatly. Then, on the basis of the previous orientation of graphene oxide layer, "negative draft" is used to make the graphene oxide obtain high orientation and regular micro-crease structure, thereby giving it excellent performance of high modulus and high toughness, which has wide application prospect.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of nanomaterials, and particularly to a preparation method of graphene oxide fiber material. BACKGROUND

[0002] In 2004, Andre Geim and Konstantin Novoselov, physicists at the University of Manchester, successfully isolated graphene from graphite by micromechanical exfoliation. Graphene is a two-dimensional single-atom layer honeycomb-like periodic lattice structure crystal composed of carbon atoms with sp2 hybridization orbitals, with a thickness of only 0.35 nm. The unique structure of graphene endows it with excellent properties, such as excellent mechanical properties, large specific surface area, large carrier mobility, and high thermal conductivity. Graphene fibers assembled from graphene nanosheet layers can realize the transfer of excellent properties of graphene at the nanoscale to the macroscopic scale. With the gradual optimization of the material system and the gradual improvement of the preparation process, graphene fibers are expected to develop into structural-functional integrated fiber materials and be applied to a wider range of fields.

[0003] Graphene oxide, as an important derivative of graphene, has attracted attention from the industry due to its ease of mass production and unique solution processing properties. In 2011, Professor Gao Chao's team at Zhejiang University prepared graphene oxide fibers based on the lyotropic liquid crystal phenomenon of graphene oxide using a wet spinning method. Currently, the wet spinning method is the most commonly used method for preparing graphene fibers due to its simplicity, high efficiency, and scalability. However, the as-spun fibers obtained by liquid crystal wet spinning inevitably introduce irregular wrinkles and other structural defects during the coagulation stage. Large-size wrinkles in the fiber are stress-sensitive and can be easily stretched and flattened under external field action in the plasticized state. Small-size wrinkles are numerous and vary in size, making them difficult to control. In low plasticization systems, the interlayer spacing of graphene oxide expands limitedly, and the deformation capacity is weak under stress, making it difficult to completely eliminate micron-scale wrinkles. These structural defects will always exist in the fiber and ultimately be inherited to the graphene fiber after chemical reduction and heat treatment, which greatly affects the overall performance of the graphene fiber material and is a major obstacle to the transfer of excellent properties of two-dimensional graphene sheets to macroscopic materials. SUMMARY

[0004] In order to overcome the above-mentioned technical defects, the purpose of the present application is to provide a preparation method of graphene oxide fiber. The present application is based on the enhancement effect of ammonium ions and oxygen-containing groups in graphene oxide to form ionic crosslinking and partially reduce oxygen-containing groups, which reorganizes the structure of graphene oxide and obtains high-orientation graphene oxide fiber with wrinkle removal; further, through reprocessing, high-performance graphene functional fiber with uniform wrinkles is obtained.

[0005] The application adopts the following technical scheme: a preparation method of graphene oxide fiber, comprising the following processes: graphene oxide fiber is soaked in an ammonium salt solution for 1-10 s, then stretched, the stretching rate is 20-30%, and the stretching is continuously performed for 3-5 s, so that the graphene oxide layers are kept in flat arrangement, and the graphene oxide fiber without wrinkles is obtained after drying; the introduction of the ammonium salt makes the graphene oxide layers chemically crosslinked and the oxygen-containing groups partially reduced, so that the interlayer electrostatic repulsion is reduced, the synergistic effect of the two aspects enhances the interlayer force, and the graphene oxide layers are endowed with the ability to bear greater load; under the stretching of the greater load, the graphene layers are stretched, the graphene layers are arranged flat, and the graphene oxide fiber without wrinkles is obtained after drying.

[0006] Further, in the step (1), the ammonium salt includes but is not limited to phenyltetraamine tetrahydrochloride, phenylenediamine hydrochloride, triaminobenzene trishydrochloride, phenylenediamine sulfate, dimethyl-p-phenylenediamine dihydrochloride, diaminohydroquinone hydrochloride and the like. The ammonium salt is easy to decompose into ammonium ions, can form ionic crosslinking with the oxygen-containing groups on the graphene oxide layers, and can partially reduce the oxygen-containing groups to reduce the interlayer electrostatic repulsion. In some preferred embodiments of the application, aromatic ammonium salt is used, which has a benzene ring structure capable of producing π-π interaction with the graphene oxide layers to provide additional interlayer force.

[0007] The graphene oxide fiber in the application is not limited to graphene oxide fiber single filaments, but can also be used for graphene oxide fiber tows.

[0008] Further, the stretching bath is water, acetic acid, ethyl acetate, ethanol, methanol, isopropanol, ethylene glycol, propylene glycol, glycerol, triethylene glycol, tetraethylene glycol, pentaethylene glycol or other mixed solvents.

[0009] Further, the graphene oxide fiber without wrinkles obtained in step 2 is further treated to obtain graphene oxide fiber with uniform wrinkles, and the treatment method is as follows: the graphene oxide fiber without wrinkles is introduced into a new stretching bath, the draft speed ratio of the front and rear take-up machines is adjusted, the stretching is performed in the mode of "negative draft", and the stretching is continuously performed for 3-5 s, so that graphene oxide fiber with regular micro-wrinkle structure is obtained. "Negative draft" means that the draft speed ratio makes the stretching multiple less than 1, and the flatly arranged graphene oxide layers generate regular micro-wrinkles in a free state, which can effectively resist brittle fracture of the fiber, thereby endowing high toughness.

[0010] The beneficial effects of the present application are that the present application provides strong interlayer force based on the ion cross-linking enhancement effect of ammonium ions and oxygen-containing groups of graphene oxide, so that it can bear larger tensile load to make the graphene oxide sheet layer arrange flat. Then, on the basis of the previous orientation arrangement of graphene oxide sheet layer, the "negative draft" is used to make the graphene oxide obtain high orientation and regular micro-crease structure, thereby giving it excellent performance of high modulus and high toughness. BRIEF DESCRIPTION OF DRAWINGS

[0011] Figure 1 For comparison of SEM images, SAXS images, and mechanical property curves of products obtained in Example 1 and Comparative Example 1, Figure 1 a in the above formula (1) and Figure 1 b in the above formula (2) are the surface morphologies of graphene oxide fibers in Example 1 and Comparative Example 1, respectively; Figure 1 c in the above formula (1) and Figure 1 d in the above formula (2) are the orientation degrees of graphene oxide fibers in Example 1 and Comparative Example 1, respectively; Figure 1 e in the above formula (1) is the mechanical property comparison of graphene oxide fibers in Example 1 and Comparative Example 1.

[0012] Figure 2 For comparison of SEM images and mechanical property curves of products obtained in Example 2 and Comparative Example 2, Figure 2 a in the above formula (1) and Figure 2 b in the above formula (2) are the surface morphologies of graphene oxide fibers in Example 2 and Comparative Example 2, respectively; Figure 2 c in the above formula (1) is the mechanical property comparison of graphene oxide fibers in Example 2 and Comparative Example 2.

[0013] Figure 3 For comparison of SEM images of products obtained in Example 3 and Comparative Example 3, Figure 3 a in the above formula (1) and Figure 3 b in the above formula (2) are the surface morphologies of graphene oxide fiber tows in Example 3 and Comparative Example 3, respectively.

[0014] Figure 4 For comparison of SEM images and mechanical property curves of products obtained in Example 4 and Comparative Example 4, Figure 4 a in the above formula (1) and Figure 4 b in the above formula (2) are the surface morphologies of graphene oxide fibers in Example 4 and Comparative Example 4, respectively; Figure 4 c in the above formula (1) is the mechanical property comparison of graphene oxide fibers in Example 4 and Comparative Example 4. DETAILED DESCRIPTION

[0015] In order to further illustrate the technical means and effects adopted by the present application to achieve the predetermined purposes, the specific embodiments, structures, features and effects according to the present application are described in detail below in combination with the drawings and preferred embodiments. EXAMPLE

[0016] (1) ethanol and water were configured into solvent in volume ratio of 4:1, and phenylenediamine hydrochloride was taken as finishing agent to be added into the solvent to prepare a structure reorganization bath with phenylenediamine hydrochloride concentration of 5mM;

[0017] (2) the wet-spun graphene oxide fiber was drawn into the structure reorganization bath to make the fiber swell, and the interlayer spacing of graphene oxide sheets was increased to 1.5nm after 1s;

[0018] (3) the graphene oxide fiber was stretched with a stretching rate of 25%, and the stretching was maintained for 5s;

[0019] (4) the graphene oxide fiber was drawn out, dried and collected to obtain high-modulus graphene oxide fiber.

[0020] Comparative Example 1

[0021] (1) ethanol and water were configured into solvent in volume ratio of 4:1;

[0022] (2) the wet-spun graphene oxide fiber was drawn into the above ethanol aqueous solution to make the fiber swell, and the interlayer spacing of graphene oxide sheets was increased to 1.5nm after 1s;

[0023] (3) the graphene oxide fiber was stretched, and the maximum stretching rate was measured to be 10%; the stretching was maintained at the maximum stretching rate for 5s;

[0024] (4) the graphene oxide fiber was drawn out, dried and collected to obtain high-modulus graphene oxide fiber.

[0025] The SEM of the products of Example 1 and Comparative Example 1 is shown in a and b of FIG. 1, respectively, wherein the small-size wrinkles of the product of Example 1 are further stretched and eliminated to make the morphology more regular and ordered; the SAXS graphs of the products of Example 1 and Comparative Example 1 are shown in c and d of FIG. 2, respectively, from which it can be seen that the orientation degree of the graphene oxide fiber obtained by adding finishing agent to assist stretching is obviously improved; the mechanical property curve of the products of Example 1 and Comparative Example 1 is shown in e of FIG. 3, from which it can be seen that the tensile strength and modulus of the graphene oxide fiber obtained by adding finishing agent aniline hydrochloride to assist stretching are greatly improved. Figure 1 Figure 1 The SEM of the products of Example 1 and Comparative Example 1 is shown in a and b of FIG. 1, respectively, wherein the small-size wrinkles of the product of Example 1 are further stretched and eliminated to make the morphology more regular and ordered; the SAXS graphs of the products of Example 1 and Comparative Example 1 are shown in c and d of FIG. 2, respectively, from which it can be seen that the orientation degree of the graphene oxide fiber obtained by adding finishing agent to assist stretching is obviously improved; the mechanical property curve of the products of Example 1 and Comparative Example 1 is shown in e of FIG. 3, from which it can be seen that the tensile strength and modulus of the graphene oxide fiber obtained by adding finishing agent aniline hydrochloride to assist stretching are greatly improved. Figure 1 Figure 1 The SEM of the products of Example 1 and Comparative Example 1 is shown in a and b of FIG. 1, respectively, wherein the small-size wrinkles of the product of Example 1 are further stretched and eliminated to make the morphology more regular and ordered; the SAXS graphs of the products of Example 1 and Comparative Example 1 are shown in c and d of FIG. 2, respectively, from which it can be seen that the orientation degree of the graphene oxide fiber obtained by adding finishing agent to assist stretching is obviously improved; the mechanical property curve of the products of Example 1 and Comparative Example 1 is shown in e of FIG. 3, from which it can be seen that the tensile strength and modulus of the graphene oxide fiber obtained by adding finishing agent aniline hydrochloride to assist stretching are greatly improved. Figure 1 Example

[0026] (1) ethanol and water were configured into solvent in volume ratio of 3:1, and phenylenediamine hydrochloride was taken as finishing agent to be added into the solvent to prepare a structure reorganization bath with phenylenediamine hydrochloride concentration of 1mM;

[0027] ​​​(2) The wet-spun graphene oxide fiber is drawn into the structure-reforming bath, so that the fiber swells, and after 10 s, the interlayer spacing of the graphene oxide sheets increases to 1.8 nm;

[0028] (3) The graphene oxide fiber is stretched at a stretching rate of 25%, and the stretching is maintained for 5 s;

[0029] (4) The graphene oxide fiber is drawn out, dried, and collected to obtain a high-modulus graphene oxide fiber.

[0030] Comparative Example 2:

[0031] (1) Ethanol and water are configured into a solvent at a volume ratio of 3:1;

[0032] (2) The wet-spun graphene oxide fiber is drawn into the above ethanol aqueous solution, so that the fiber swells, and after 10 s, the interlayer spacing of the graphene oxide sheets increases to 1.8 nm;

[0033] (3) The graphene oxide fiber is stretched at a maximum stretching rate of 7%, and the stretching is maintained for 5 s;

[0034] (4) The graphene oxide fiber is drawn out, dried, and collected to obtain a high-modulus graphene oxide fiber.

[0035] The SEM of the products of Example 2 and Comparative Example 2 is shown in Figs. a and b in Figure 2 , respectively. As can be seen from the figures, the small-size wrinkles of the graphene oxide fiber are further stretched and eliminated, so that the morphology thereof is more regular and ordered, and the orientation degree is higher. Figure 2 The mechanical property curves of the products of Example 1 and Comparative Example 1 are shown in Fig. c in Figure 2 . As can be seen from the figure, through the addition of the finishing agent phenylene diamine tetrahydrochloride to assist stretching, the strength and modulus of the graphene oxide fiber are greatly improved. Example

[0036] (1) Ethanol and water are configured into a solvent at a volume ratio of 4:1, and phenylene diamine tetrahydrochloride is taken as a finishing factor and added into the solvent to prepare a structure-reforming bath with a phenylene diamine tetrahydrochloride concentration of 10 mM;

[0037] (2) A graphene oxide fiber bundle obtained by wet spinning from 100 nozzles of a spinneret with a nozzle diameter of 120 microns is drawn into the structure-reforming bath, so that the fiber bundle swells, and after 10 s, the interlayer spacing of the graphene oxide sheets increases to 1.5 nm;

[0038] (3) The graphene oxide fiber bundle is positively drawn at a stretching rate of 20%, and the stretching is maintained for 5 s;

[0039] (4) The graphene oxide fiber bundle is pulled out, dried and collected to obtain a high modulus graphene oxide fiber bundle.

[0040] Comparative Example 3

[0041] (1) Ethanol and water are configured into a solvent in a volume ratio of 4:1;

[0042] (2) 100 graphene oxide fiber bundles obtained by wet spinning from a 100-hole spinneret with a hole diameter of 120 microns are pulled into the above ethanol aqueous solution to cause the fiber bundle to swell, and after 10s, the graphene oxide interlayer spacing is increased to 1.5 nm;

[0043] (3) The graphene oxide fiber bundle is positively stretched at a maximum stretching rate of 5% for 5s;

[0044] (4) The graphene oxide fiber bundle is pulled out, dried and collected to obtain a high modulus graphene oxide fiber bundle.

[0045] The SEM of the products of Example 3 and Comparative Example 3 is shown in FIGS. a and b in Figure 3 Figure 3 From the figures, it can be seen that after adding the finishing agent benzene tetramine tetrahydrochloride to assist stretching, the small size wrinkles of the graphene oxide fiber bundle are further stretched and eliminated, making the morphology more regular and ordered and the degree of orientation higher. Example

[0046] (1) Ethanol and water are configured into a solvent in a volume ratio of 3:1, and benzene tetramine tetrahydrochloride is taken as a finishing agent and added to the solvent to prepare a structure reorganization bath with a benzene tetramine tetrahydrochloride concentration of 5mM;

[0047] (2) The graphene oxide fiber obtained by wet spinning is pulled into the structure reorganization bath to cause the fiber to swell, and after 8s, the graphene oxide interlayer spacing is increased to 1.8 nm;

[0048] (3) The graphene oxide fiber is stretched at a stretching rate of 25% for 5s;

[0049] (4) The graphene oxide fiber stretched by 25% in step (3) is pulled into a stretching bath prepared by configuring ethanol and water in a volume ratio of 3:1 to implement negative stretching, and the speed ratio of the front and rear yarn collection spindles is 10:11, and the continuous stretching lasts for 5s.

[0050] (5) The graphene oxide fiber is pulled out, dried and collected to obtain a high toughness graphene oxide fiber.

[0051] Comparative Example 4

[0052] ​(1) Prepare a structural reforming bath with a concentration of 5 mM phenyltetrahydrochloric acid by mixing ethanol and water in a volume ratio of 3:1, and add phenyltetrahydrochloric acid as a conditioning factor to the solvent.

[0053] (2) The graphene oxide fibers obtained by wet spinning were drawn into the structural reforming bath, causing the fibers to swell. After 8 seconds, the interlayer spacing of the graphene oxide sheets increased to 1.8 nm.

[0054] (3) Stretch the graphene oxide fiber with a stretch rate of 25% and hold the stretch for 5 seconds;

[0055] (4) The graphene oxide fibers are pulled out, dried and collected to obtain high modulus graphene oxide fibers.

[0056] SEM images of the products of Example 4 and Comparative Example 4 are shown below. Figure 4 a and Figure 4 As shown in figure b, the fibers obtained by negative stretching have certain regular micro-folds, which can effectively resist brittle fiber fracture. The mechanical property curves of the products in Example 4 and Comparative Example 4 are shown below. Figure 4 As shown in the figure, the fiber elongation at break is significantly improved after negative stretching, while the strength remains basically unchanged.

[0057] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A method for preparing graphene oxide material, characterized in that, The process includes the following steps: immersing graphene oxide fiber bundles in an ammonium salt solution for 1-10 seconds, then stretching them to a stretch rate of 20-30% for 3-5 seconds to maintain the straight alignment of the graphene oxide sheets. After drying, wrinkle-free graphene oxide fiber bundles are obtained. The concentration of the ammonium salt is 1 mM-10 mM, and the solvent for the ammonium salt solution is water, acetic acid, ethyl acetate, ethanol, methanol, isopropanol, ethylene glycol, propylene glycol, glycerol, triethylene glycol, tetraethylene glycol, or pentaethylene glycol. The ammonium salt is phenyltetramine tetrahydrochloride, phenylenediamine hydrochloride, triaminophenyltrihydrochloride, phenylenediamine sulfate, dimethyl-p-phenylenediamine dihydrochloride, or diaminoresorcinol hydrochloride.

2. The preparation method according to claim 1, characterized in that, It also includes negative stretching of de-wrinkled graphene oxide fiber bundles to obtain graphene oxide fiber bundles with uniform wrinkles. The negative stretching method is as follows: the de-wrinkled graphene oxide fiber bundles are introduced into a new stretching bath, the ratio of the front and rear winding speeds is adjusted to below 1:1, and held for 3-5 seconds to obtain graphene oxide fiber bundles with regular micro-wrinkled structures.

Images