Graphene-modified aramid III fiber and its preparation method

Abstract

This invention discloses a graphene-modified aramid III fiber and its preparation method. The graphene in the graphene-modified aramid III fiber is covalently bonded to an aramid III polymer. The preparation method involves modifying the graphene surface with amine groups, thereby enabling the graphene to be uniformly dispersed in N,N-dimethylacetamide, an organic solvent required for the preparation of aramid III. Then, during the polymerization of aramid III, an in-situ polymerization process is added to composite the graphene and aramid III. The amine groups on the prepared amino-modified graphene can form covalent bonds with aramid III, improving the bonding tightness between graphene and the fiber, thereby enhancing the mechanical properties of the fiber.

Description

Technical Field

[0001] This invention belongs to the field of graphene application technology, specifically relating to a graphene-modified aramid III fiber and its preparation method. Background Technology

[0002] Graphene is a material composed of carbon atoms arranged in sp... 2 Hybridized orbitals form a hexagonal honeycomb lattice planar thin film with a thickness equivalent to one carbon atom layer (0.35 nm). Graphene possesses unique physicochemical properties; it is the hardest known material, with a Young's modulus exceeding 1000 GPa, while also exhibiting good toughness; its thermal conductivity is 3000 W / mK; and its charge migration velocity is 2 × 10⁻⁶. 5 cm 2 / Vs; Specific surface area up to 2600m² 2 / g. Graphene oxide (GO) is a type of functionalized graphene with functional groups introduced onto graphene sheets, giving it certain new properties. The functional groups include hydroxyl and epoxy groups on the basal surface of graphene oxide, as well as carboxyl and hydroxyl groups at the edges. The surface groups of graphene oxide can be used to perform composite reactions with other materials. Among them, functionalized graphene with the introduction of other groups has a wide range of applications in polymer composites.

[0003] Aramid III fiber is an important material for national defense and military industries, playing a crucial role in high-end fields such as defense and aerospace. It can be used as a structural material for bulletproof armor or rockets. Currently, the tensile strength of domestically produced aramid III has reached 5.0 GPa, and the tensile modulus reaches 130-160 GPa. Given relatively mature formulations and processes, the most effective and direct way to further improve the mechanical properties of aramid III fiber is to composite it with materials that have even better mechanical properties. Graphene, as a novel nanomaterial of carbon, possesses extremely high strength and modulus, and it holds promise for further improving the mechanical properties of aramid III through composite processes.

[0004] To achieve the desired reinforcement effect, the dispersibility of graphene in the fiber is crucial. To achieve good dispersibility, graphene is typically first dispersed in a specific solvent, and then composited with aramid III via in-situ polymerization. However, N,N-dimethylacetamide, a solvent used in the preparation of aramid III, cannot effectively disperse graphene oxide, thus failing to yield modified aramid III fibers with ideal mechanical properties. Summary of the Invention

[0005] To address the above problems, this invention provides a graphene-modified aramid III fiber and its preparation method.

[0006] In one aspect, the present invention provides a graphene-modified aramid III fiber, wherein the graphene contained in the graphene-modified aramid III fiber is covalently bonded to the aramid III polymer.

[0007] According to one embodiment of the present invention, the covalent bond is an amide bond.

[0008] According to another embodiment of the present invention, the total mass of the graphene-modified aramid III fiber is 100%, and the mass content of the graphene is 0.05-10 wt%.

[0009] According to another embodiment of the present invention, the graphene in the graphene-modified aramid III fiber has a size of 100 nm-1 μm.

[0010] According to another embodiment of the present invention, the graphene-modified aramid III fiber has a tensile strength of 30-35 cN / dTex and a tensile modulus of 900-1000 cN / dTex.

[0011] Another aspect of the present invention provides a method for preparing the above-mentioned graphene-modified aramid III fiber, comprising: S1, dispersing graphene with amine groups on its surface in N,N-dimethylacetamide to form a uniformly dispersed first dispersion; S2, adding the first dispersion during the polymerization process of forming the aramid III polymer.

[0012] According to one embodiment of the present invention, the preparation process of the graphene with surface modified with amine groups includes: S01, adding graphene oxide to N,N-dimethylacetamide, dispersing it evenly, and then crushing the graphene oxide to form a second dispersion; S02, adding a compound having at least two amine groups to the second dispersion to react with the graphene oxide to graft amino functional groups onto the graphene surface.

[0013] According to another embodiment of the present invention, in step S01, the concentration of graphene oxide in the second dispersion is 2 to 50 mg / mL.

[0014] According to another embodiment of the present invention, the mass of the compound having at least two amine groups added in the S02 step is equivalent to 50 to 250% of the mass of the graphene oxide.

[0015] According to another embodiment of the present invention, the compound having at least two amino groups is selected from one or more of m-phenylenediamine, p-phenylenediamine, m-aminobenzylamine, and p-aminobenzylamine.

[0016] This invention modifies the surface of graphene with amine groups, thereby enabling the graphene to be uniformly dispersed in N,N-dimethylacetamide, the organic solvent required for the preparation of aramid III. This allows for the in-situ polymerization of graphene and aramid III during the polymerization process, enabling the composite formation of graphene and aramid III. The amine groups on the prepared amino-modified graphene can form covalent bonds with aramid III, improving the bonding tightness between graphene and the fiber, thus enhancing the mechanical properties of the fiber. Attached Figure Description

[0017] Figure 1 A schematic diagram of the synthesis mechanism of functionalized graphene.

[0018] Figure 2 The image shows a comparison of the infrared spectra of amino-based graphene and graphene oxide in Example 1 and Comparative Example 1.

[0019] Figure 3 This is a comparison diagram of the dispersion of amino-modified graphene oxide and graphene oxide in N,N-dimethylacetamide in Example 1 and Comparative Example 1.

[0020] Figure 4 The mechanical properties of the amino-based graphene / aramid III composite fiber and the graphene oxide / aramid III composite fiber in Example 1 and Comparative Example 1 are shown in the graphs. Detailed Implementation

[0021] The technical solution of the present invention will be described in detail below with reference to the accompanying drawings and embodiments. However, the description of the embodiments is only a part of the embodiments of the present invention and is not limited thereto.

[0022] The graphene-modified aramid III fiber of the present invention contains graphene that is covalently linked to an aramid III polymer.

[0023] In an alternative implementation, the covalent bond is an amide bond.

[0024] In an optional embodiment, the total mass of graphene-modified aramid III fibers is 100%, and the mass content of graphene is 0.05-10 wt%. If the graphene content in the modified fiber is less than 0.05 wt%, the improvement in mechanical properties is not significant; if it is greater than 10 wt%, it will affect the spinning effect.

[0025] In an optional embodiment, the graphene in the graphene-modified aramid III fiber has a size of 100 nm to 1 μm.

[0026] In an optional embodiment, the graphene-modified aramid III fiber has a tensile strength of 30-35 cN / dTex and a tensile modulus of 900-1000 cN / dTex.

[0027] The graphene-modified aramid III fiber of the present invention can be prepared by the following method. The preparation method includes: S1, dispersing graphene with amine groups on its surface in N,N-dimethylacetamide to form a uniformly dispersed first dispersion; S2, adding the first dispersion during the polymerization process of forming the aramid III polymer. The designations S1 and S2 for the above steps and S01 and S02 for the following steps in this patent are only used to distinguish different steps and are not intended to limit the steps to being adjacent; other auxiliary steps may be included between two steps.

[0028] In the preparation method of this invention, graphene with amino groups on its surface is dispersed in N,N-dimethylacetamide, an organic solvent required for the preparation of aramid III. The amino groups improve the wettability of graphene with N,N-dimethylacetamide, thereby forming a uniform first dispersion. Adding this uniformly dispersed first dispersion during the polymerization of aramid III allows the amino-containing graphene to react with the monomers forming aramid III through these amino groups, thus covalently linking the graphene to the aramid III polymer. The modified fibers formed by this method exhibit uniform dispersion of graphene within the fibers, resulting in fibers with more ideal mechanical properties.

[0029] After step S2, the polymer solution that has completed the polymerization reaction can be spun into modified fibers. The specific spinning method and steps can be any suitable manner.

[0030] In an optional embodiment, the preparation process of graphene with surface-modified amine groups includes: S01, adding graphene oxide to N,N-dimethylacetamide, dispersing it evenly, and then crushing the graphene oxide to form a second dispersion; S02, adding a compound having at least two amine groups to the second dispersion and reacting it with the graphene oxide to graft amine functional groups onto the graphene surface.

[0031] In step S01, the concentration of graphene oxide in the second dispersion is 2–50 mg / mL. Ultrasonic treatment can be used to uniformly disperse the graphene oxide in the solvent, or other suitable dispersion methods can be employed. The graphene oxide is then broken down to achieve the desired size. This breaking down can be done using a cell disruptor or other methods capable of breaking the graphene oxide to the predetermined size. The size of the broken graphene oxide matches well with the size of aramid III, and the resulting amination-treated, amino-modified graphene can enhance the performance of aramid III.

[0032] In step S02, a compound having at least two amino groups reacts with the oxygen-containing groups on the surface of graphene oxide, grafting the amino groups onto the graphene surface. The compound having at least two amino groups has high solubility in the organic solvent N,N-dimethylacetamide; therefore, using N,N-dimethylacetamide as a solvent in step S1 reduces the amount of solvent used during the amination process. The mass of the compound having at least two amino groups added in this step is equivalent to 50–250% of the mass of graphene oxide. The reaction can be carried out under a protective atmosphere at a temperature between 20 and 120°C for 12–24 hours to ensure complete reaction between the compound having at least two amino groups and the oxygen-containing groups on the graphene.

[0033] After the reaction, the amination-modified graphene can be filtered out, washed, and dried. It can be washed several times with ethanol and deionized water before drying. The prepared amination-modified graphene exhibits excellent dispersibility in the organic solvent N,N-dimethylacetamide. The prepared amination-modified graphene can reinforce aramid III fibers. The entire preparation process of amination-modified graphene is simple, suitable for mass production, and the obtained product can be directly used for composite reinforcement of aramid III fibers.

[0034] In an optional embodiment, the compound having at least two amino groups is selected from any one or more of 1,3-phenylenediamine (m-phenylenediamine), 1,4-phenylenediamine (p-phenylenediamine), 3-aminobenzylamine (m-aminobenzylamine), and 4-aminobenzylamine (p-aminobenzylamine).

[0035] The following can be combined Figure 1 Using p-phenylenediamine as an example, we will explain the process of forming surface-modifying groups from compounds with at least two amine groups. As shown in the figure, phenylenediamine reacts with oxygen-containing groups on the graphene oxide surface and attaches to it.

[0036] The present invention will be further described below through specific examples. However, these examples are merely exemplary and do not constitute any limitation on the scope of protection of the present invention.

[0037] Unless otherwise specified, all reagents, materials and instruments used in the following examples and comparative examples are commercially available.

[0038] Example 1

[0039] 1 g of monolayer graphene oxide with a sheet diameter less than 1 μm was added to 200 mL of N,N-dimethylacetamide. The mixture was sonicated at 300 W for 30 min to ensure thorough dispersion. The resulting suspension was then poured into a 500 mL beaker and cell-disrupted at 5 °C for 1 h at 900 W. The dispersed graphene oxide was then transferred to a round-bottom flask, and 1 g of p-phenylenediamine was added. The flask was then placed in an oil bath with nitrogen as a protective gas. The oil bath was heated to 120 °C and reacted for 24 h. The solution was then poured out of the flask and filtered through a 0.22 μm filter. The resulting filter cake was washed twice with ethanol and then twice with deionized water. The filter cake was then vacuum-dried in a 120 °C oven. Finally, the dried functionalized graphene was added to 500 mL of N,N-dimethylacetamide to prepare a dispersion of 2 mg / mL, thus obtaining a functionalized graphene dispersion suitable for aramid III fiber composite reinforcement.

[0040] The dispersion was added during the polymerization of aramid III, and the tensile strength of the amino-based graphene / aramid III composite fiber prepared by wet spinning was measured to be 34.26 cN / dTex, and the tensile modulus was measured to be 965.5 cN / dTex.

[0041] Example 2

[0042] Two g of monolayer graphene oxide with a sheet diameter less than 5 μm was added to 800 mL of N,N-dimethylacetamide. The mixture was sonicated at 500 W for 30 min to ensure thorough dispersion. The resulting suspension was then poured into a 2000 mL beaker and subjected to cell disruption at 5 °C for 1.5 h at 2000 W. The dispersed graphene oxide was then transferred to a round-bottom flask, and 4 g of m-phenylenediamine was added. The flask was then placed in an oil bath with nitrogen as a protective gas. The oil bath was heated to 60 °C and reacted for 24 h. The solution was then poured out of the flask and filtered through a 0.22 μm filter. The resulting filter cake was washed twice with ethanol and then twice with deionized water. The filter cake was then vacuum-dried in an oven at 120 °C. Finally, the dried functionalized graphene was added to 1000 mL of N,N-dimethylacetamide to prepare a dispersion of 2 mg / mL, thus obtaining a functionalized graphene dispersion suitable for aramid III fiber composite reinforcement.

[0043] The dispersion was added during the polymerization of aramid III, and the tensile strength of the amino-based graphene / aramid III composite fiber prepared by wet spinning was measured to be 33.76 cN / dTex, and the tensile modulus was measured to be 946.90 cN / dTex.

[0044] Example 3

[0045] Two g of monolayer graphene oxide with a sheet diameter less than 1 μm was added to 800 mL of N,N-dimethylacetamide. The mixture was sonicated at 500 W for 30 min to ensure thorough dispersion. The resulting suspension was then poured into a 2000 mL beaker and cell-disrupting at 5 °C for 1.5 h at 2000 W. The dispersed graphene oxide was then transferred to a round-bottom flask, and 2 g of 4-aminobenzylamine was added. Nitrogen gas was introduced as a protective gas. The reaction was carried out at 25 °C for 24 h. The solution was then poured out of the round-bottom flask and filtered through a 0.22 μm filter. The resulting filter cake was washed twice with ethanol and then twice with deionized water. Finally, the filter cake was vacuum-dried in an oven at 120 °C. Finally, the dried functionalized graphene was added to 1000 mL of N,N-dimethylacetamide to prepare a dispersion of 2 mg / mL, thus obtaining a functionalized graphene dispersion suitable for aramid III fiber composite reinforcement.

[0046] The dispersion was mixed with aramid III monomer and then polymerized. The tensile strength of the amino-based graphene / aramid III composite fiber prepared by wet spinning was measured to be 34.14 cN / dTex, and the tensile modulus was measured to be 930.85 cN / dTex.

[0047] Example 4

[0048] Two g of monolayer graphene oxide with a sheet diameter less than 10 μm was added to 800 mL of N,N-dimethylacetamide. The mixture was sonicated at 500 W for 30 min to ensure thorough dispersion. The resulting suspension was then poured into a 2000 mL beaker and cell-disrupting at 5 °C for 1.5 h at 2000 W. The dispersed graphene oxide was then transferred to a round-bottom flask, and 2 g of 4-aminobenzylamine was added. Nitrogen gas was introduced as a protective gas. The reaction was carried out at 25 °C for 24 h. The solution was then poured out of the round-bottom flask and filtered through a 0.22 μm filter. The resulting filter cake was washed twice with ethanol and then twice with deionized water. Finally, the filter cake was vacuum-dried in an oven at 120 °C. Finally, the dried functionalized graphene was added to 1000 mL of N,N-dimethylacetamide to prepare a dispersion of 2 mg / mL, thus obtaining a functionalized graphene dispersion suitable for aramid III fiber composite reinforcement.

[0049] The dispersion was mixed with aramid III monomer and then polymerized. The tensile strength of the amino-based graphene / aramid III composite fiber prepared by wet spinning was measured to be 30.24 cN / dTex, and the tensile modulus was measured to be 963.44 cN / dTex.

[0050] Example 5

[0051] 1 g of monolayer graphene oxide with a sheet diameter less than 5 μm was added to 200 mL of N,N-dimethylacetamide and sonicated at 300 W for 30 min to ensure thorough dispersion. The resulting suspension was then poured into a 500 mL beaker and cell-disrupted at 5 °C for 1 h at 900 W. The dispersed graphene oxide was then transferred to a round-bottom flask, and 2 g of p-phenylenediamine was added. The flask was then placed in an oil bath with nitrogen as a protective gas. The oil bath was heated to 80 °C and reacted for 24 h. The solution was then poured out of the round-bottom flask and filtered through a 0.22 μm filter. The resulting filter cake was washed twice with ethanol and then twice with deionized water. Finally, the filter cake was vacuum dried in an oven at 120 °C. Finally, the dried functionalized graphene was added to 500 mL of N,N-dimethylacetamide to prepare a dispersion of 2 mg / mL, thus obtaining a functionalized graphene dispersion suitable for aramid III fiber composite reinforcement.

[0052] The dispersion was added during the polymerization of aramid III, and the tensile strength of the amino-based graphene / aramid III composite fiber prepared by wet spinning was measured to be 31.78 cN / dTex, and the tensile modulus was measured to be 951.65 cN / dTex.

[0053] Example 6

[0054] 1 g of monolayer graphene oxide with a sheet diameter less than 5 μm was added to 200 mL of N,N-dimethylacetamide and sonicated at 300 W for 30 min to ensure thorough dispersion. The resulting suspension was then poured into a 500 mL beaker and cell-disrupted at 5 °C for 1 h at a power of 900 W. The dispersed graphene oxide was then poured into a round-bottom flask, and 1 g of p-phenylenediamine was added. The flask was then placed in an oil bath with nitrogen as a protective gas. The oil bath was heated to 60 °C and reacted for 24 h. The solution was then poured out of the round-bottom flask and filtered through a 0.22 μm filter. The resulting filter cake was washed twice with ethanol and then twice with deionized water. Finally, the filter cake was vacuum dried in an oven at 120 °C. Finally, the dried functionalized graphene was added to 500 mL of N,N-dimethylacetamide to prepare a dispersion of 2 mg / mL, thus obtaining a functionalized graphene (p-phenylenediamine graphene oxide) dispersion suitable for aramid III fiber composite reinforcement.

[0055] The dispersion was added during the polymerization of aramid III, and the tensile strength of the amino-based graphene / aramid III composite fiber prepared by wet spinning was measured to be 32.95 cN / dTex, and the tensile modulus was measured to be 900.23 cN / dTex.

[0056] Example 7

[0057] 1 g of monolayer graphene oxide with a sheet diameter less than 5 μm was added to 200 mL of N,N-dimethylacetamide and sonicated at 300 W for 30 min to ensure thorough dispersion. The resulting suspension was then poured into a 500 mL beaker and cell-disrupted at 5 °C for 1 h at a power of 900 W. The dispersed graphene oxide was then poured into a round-bottom flask, and 1 g of ethylenediamine was added. The flask was then placed in an oil bath with nitrogen as a protective gas. The oil bath was heated to 60 °C and reacted for 24 h. The solution was then poured out of the round-bottom flask and filtered through a 0.22 μm filter. The resulting filter cake was washed twice with ethanol and then twice with deionized water. Finally, the filter cake was vacuum dried in an oven at 120 °C. Finally, the dried functionalized graphene was added to 500 mL of N,N-dimethylacetamide to prepare a dispersion of 2 mg / mL, thus obtaining a functionalized graphene (ethylenediamine graphene oxide) dispersion suitable for aramid III fiber composite reinforcement.

[0058] The dispersion was added during the polymerization of aramid III, and the tensile strength of the amino-based graphene / aramid III composite fiber prepared by wet spinning was measured to be 33.85 cN / dTex, and the tensile modulus was measured to be 970.3 cN / dTex.

[0059] Comparative Example 1

[0060] 1g of monolayer graphene oxide with a diameter of less than 5μm was added to 200mL of N,N-dimethylacetamide and sonicated at 300W for 30min to fully disperse the graphene oxide. The resulting suspension was then poured into a 500mL beaker and cell-crushed at 5℃ for 2h at a crushing power of 600W.

[0061] The dispersion was added during the polymerization of aramid III, and the tensile strength of the graphene oxide / aramid III composite fiber prepared by wet spinning was measured to be 25.19 cN / dTex, and the tensile modulus was measured to be 856.60 cN / dTex.

[0062] Comparative Example 2

[0063] 1g of monolayer graphene oxide with a diameter of less than 5μm was added to 200mL of N,N-dimethylacetamide and sonicated at 300W for 30min to fully disperse the graphene oxide. The resulting suspension was then poured into a 500mL beaker and cell-crushed at 5℃ for 1h at a crushing power of 900W.

[0064] The dispersion was mixed with aramid III monomer and then polymerized. The resulting graphene oxide / aramid III composite fiber, prepared by wet spinning, had a tensile strength of 26.11 cN / dTex and a tensile modulus of 859.74 cN / dTex.

[0065] Figure 2 This is a comparison of the infrared spectra of amino-based graphene and graphene oxide in Example 1 and Comparative Example 1. From... Figure 2 The results show that the amine groups on compounds with at least two amine groups undergo amidation reactions with the carboxyl groups on graphene oxide, confirming the presence of amine groups on amino-based graphene.

[0066] Figure 3 This is a comparison diagram of the dispersion of amino-modified graphene oxide and graphene oxide in N,N-dimethylacetamide in Example 1 and Comparative Example 1. Figure 3 As can be seen, the dispersion of amino-modified graphene oxide in N,N-dimethylacetamide is higher.

[0067] Figure 4 These are mechanical property test graphs of the amino-based graphene / aramid III composite fiber and the graphene oxide / aramid III composite fiber in Example 1 and Comparative Example 1. From... Figure 4 It can be seen that the mechanical properties of the amino-based graphene composite fiber have been greatly improved.

[0068] The types of amine compounds used to form the fibers in Examples 1-6 and Comparative Examples 1-2, as well as the tensile strength and tensile modulus of the fibers, are shown in Table 1.

[0069] Table 1

[0070]

[0071]

[0072] As shown in Table 1, grafting amine compounds onto graphene forms covalent bonds with the fibers during polymerization, resulting in a significant improvement in mechanical properties. Different types of amine compounds exhibit varying mechanical properties, which are related to their stability and rigidity. The amount of amine compound used and the amination temperature are also extremely important, as they directly determine the degree of reductive amination and greatly influence subsequent mechanical properties.

[0073] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. A method for preparing graphene-modified aramid III fiber, characterized in that, include: S1, Graphene with amine groups on its surface is dispersed in N,N-dimethylacetamide to form a uniformly dispersed first dispersion; S2, the first dispersion is added during the polymerization process to form the aramid III polymer; The preparation process of the surface-modified amine-group graphene includes: S01, graphene oxide is added to N,N-dimethylacetamide, dispersed evenly, and then the graphene oxide is crushed to form a second dispersion; S02, a compound having at least two amine groups is added to the second dispersion to react with the graphene oxide to graft amino functional groups onto the graphene surface; The compound having at least two amine groups is selected from one or more of m-phenylenediamine, p-phenylenediamine, m-aminobenzylamine, and p-aminobenzylamine; The organic solvent required for preparing the aramid III polymer is N,N-dimethylacetamide.

2. The method for preparing graphene-modified aramid III fiber according to claim 1, characterized in that, In step S01, the concentration of graphene oxide in the second dispersion is 2-50 mg / mL.

3. The method for preparing graphene-modified aramid III fiber according to claim 1, characterized in that, The mass of the compound having at least two amine groups added in step S02 is equivalent to 50 to 250% of the mass of the graphene oxide.

4. A graphene-modified aramid III fiber, characterized in that, Prepared by the preparation method according to any one of claims 1-3.

5. The graphene-modified aramid III fiber according to claim 4, characterized in that, The graphene-modified aramid III fiber has a total mass of 100%, and the graphene content is 0.05-10 wt%.

6. The graphene-modified aramid III fiber according to claim 4, characterized in that, The graphene in the graphene-modified aramid III fiber has a size of 100 nm to 1 μm.

7. The graphene-modified aramid III fiber according to claim 4, characterized in that, The graphene-modified aramid III fiber has a tensile strength of 30-35 cN / dTex and a tensile modulus of 900-1000 cN / dTex.

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