Porous graphene modified aramid iii composite fiber and preparation method thereof

Abstract

The application discloses a graphene modified aramid III composite fiber and a preparation method thereof. The composite fiber comprises porous graphene and aramid III polymer, and the main chain of the aramid III polymer passes through the pores of the porous graphene. The graphene powder is combined with the main chain of the aramid III molecule by in-situ low-temperature polycondensation, so that the molecular chain of the aramid III is combined with the graphene closely, and the interaction force between the molecular chains of the aramid III is effectively enhanced. The application aims to provide a high-strength and high-modulus graphene / aramid III composite fiber and a complete production method for efficient spinning from polymerization to wet continuous stabilization.

Description

Technical Field

[0001] This invention relates to the field of graphene application technology, and more specifically to graphene-modified aramid III composite fibers and their preparation methods. Background Technology

[0002] Aromatic polyamide fibers, or aramid fibers for short, are long-chain polymers formed by the reaction of aromatic diamines and aromatic diacyl chlorides. The main molecular chain contains at least 85% amide groups and two aromatic rings linked together. Aramid is a high-performance material with excellent properties such as high strength, high modulus, high temperature resistance, acid and alkali resistance, light weight, aging resistance, and long lifespan. Based on their structure, aramid fibers are mainly divided into three series: Aramid I (1313, PMIA), Aramid II (1414, PPTA), and Aramid III (heterocyclic aramid). Aramid I and Aramid II were the first two aramid materials developed. While their chemical structures are similar, their properties differ significantly, leading to different applications. Heterocyclic aramid (aramid III) is a new material with a unique structure and excellent performance that has been developed in recent years. In addition to the excellent properties of the other two types of aramid, it often has better processing performance and heat resistance. The innovative introduction of a third monomer, 2-(4-aminophenyl)-5(6)-aminobenzimidazole, into the structure of aramid III allows the polymer molecules to achieve maximum axial orientation during the spinning and stretching process, and improves the crystal structure during high temperature and heat treatment, thereby significantly improving tensile strength and modulus. Comparative test results show that the breaking strength and elastic modulus of aramid III Armos are 30% and 20% higher than those of aramid II Kevlar 49, respectively. Aramid III fiber has superior comprehensive performance and occupies an irreplaceable important position among high-performance fibers. It is widely used in aerospace, defense, and civilian cutting-edge materials applications. Due to the outstanding advantages of heterocyclic aramid, it has a wide range of applications in aerospace, defense, automotive industry, protective clothing, and sports equipment.

[0003] Theoretically, aramid III can achieve a strength and modulus exceeding 30 GPa and 182 MPa, respectively. However, the tensile strength of current heterocyclic aramid fibers is far below their theoretical values. This phenomenon is mainly due to the inherent limitations of current aramid synthesis and fiber forming processes. Therefore, improving the mechanical properties of aramid III has become an urgent problem to be solved. Summary of the Invention

[0004] To address the above problems, this invention provides a graphene-modified aramid III composite fiber and its preparation method.

[0005] One aspect of the present invention provides a graphene-modified aramid III composite fiber, the composite fiber comprising porous graphene and aramid III polymer, wherein the main chain of the aramid III polymer passes through the pores of the porous graphene.

[0006] According to one embodiment of the present invention, the porous graphene has a particle size of 1-5 μm and has 2-5 layers.

[0007] According to another embodiment of the present invention, the content of the porous graphene is 0.01wt%-1wt%.

[0008] According to another embodiment of the present invention, the porous graphene has a pore density of 0.08-1.6 m³ / s. 3 g -1 .

[0009] According to another embodiment of the present invention, the graphene-modified aramid III composite fiber has a breaking strength of 32-34 cN / dtex, an elastic modulus of 810-900 cN / dtex, and an elongation at break of 3.8-4.2%.

[0010] Another aspect of the present invention provides a method for preparing the above-mentioned graphene-modified aramid III composite fiber, comprising: S1, adding a porous redox graphene dispersion to a solution containing monomers for preparing aramid III polymers, mixing evenly, and then allowing the monomers to undergo a condensation reaction to form a polymer solution.

[0011] According to one embodiment of the present invention, the preparation method further includes: S2, wet spinning the polymer solution.

[0012] According to another embodiment of the present invention, the polymer solution has a solid content of 4.2 wt% and a dynamic viscosity of 40,000-60,000.

[0013] This invention combines graphene powder with the aramid III molecular backbone through in-situ low-temperature polycondensation, thereby tightly binding the aramid III molecular chains with graphene and effectively enhancing the interaction forces between the aramid III molecular chains. The aim is to provide a complete production method for high-strength, high-modulus graphene / aramid III composite fiber and its continuous, stable, and efficient spinning process from polymerization to wet spinning, with a complete process system. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the synthesis of porous graphene in Example 1.

[0015] Figure 2 and Figure 3 The image shows the characterization of porous graphene in Example 1.

[0016] Figure 4The graph shows the characterization of the porous graphene / aramid III polymer solution in Example 1.

[0017] Figure 5 This is a SEM image of the porous graphene / aramid III composite fiber in Example 1. Detailed Implementation

[0018] The present invention will now be described in detail with reference to specific embodiments.

[0019] The graphene-modified aramid III composite fiber of the present invention comprises porous graphene and an aramid III polymer, wherein the main chain of the aramid III polymer passes through the pores of the porous graphene. The porous structure induces aramid III molecules to pass through the graphene, thereby enhancing the interchain forces of the aramid III molecules and forming a chemically stable graphene / aramid III composite. Simultaneously, the introduction of porous redox graphene can make the surface and internal structure of the aramid fiber more compact. Therefore, the mechanical properties of the fiber are comprehensively improved.

[0020] In optional embodiments, the porous graphene has a particle size of 1-5 μm and 2-5 layers. Those skilled in the art can select appropriate particle size and number of layers, for example, but not limited to, particle sizes of 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, etc., and the number of layers can be 2, 3, 4, or 5.

[0021] In an optional embodiment, the content of porous graphene is 0.01wt%-1wt%. If the content of porous graphene is too low (below 0.01wt%), the reinforcing effect is not significant; if the content is greater than 1wt%, the dispersibility is poor, affecting the performance of the fiber.

[0022] In an optional embodiment, the porous graphene has a pore density of 0.08-1.6 m³. 3 g -1 The "pore density of porous graphene" mentioned in this patent refers to the total pore volume obtained by isothermal adsorption-desorption testing of graphene powder using a specific surface area analyzer. When the pore density is below 0.08 m³ / s... 3 g -1 At this stage, the improvement in fiber properties is not significant; when the pore density is greater than 1.6m... 3 g -1 If the intrinsic structure of graphene is severely damaged, it will not provide any reinforcing effect. Graphene oxide can be obtained through the Hummer's method, and then porous reduced-oxidation graphene can be obtained through hydrogen peroxide pore-forming. The pore density of the porous graphene can be controlled by adjusting the oxidation time. Of course, other feasible methods can also be used to obtain porous graphene.

[0023] In an optional embodiment, the graphene-modified aramid III composite fiber has a breaking strength of 32-34 cN / dtex, an elastic modulus of 810-900 cN / dtex, and an elongation at break of 3.8-4.2%.

[0024] The preparation method of the above-mentioned graphene-modified aramid III composite fiber includes: S1, adding a porous redox graphene dispersion to a solution containing monomers for preparing aramid III polymers, mixing evenly, and then allowing the monomers to undergo a condensation reaction to form a polymer solution. This invention, by adding porous graphene before or during polymerization, allows the porous structure to induce aramid III molecules to pass through the graphene, thereby enhancing the interchain forces of the aramid III molecules and forming a chemically stable graphene / aramid composite, comprehensively improving the mechanical properties of the composite fiber.

[0025] In an optional embodiment, the preparation method further includes: S2, wet spinning the polymerization solution. The polymerization solution has a solid content of 4.2 wt% and a dynamic viscosity of 40,000-60,000.

[0026] The following combination Figure 1 The inventive concept of the present invention is explained with specific embodiments, but those skilled in the art will understand that the present invention is not intended to be limited to these specific embodiments.

[0027] (1) Preparation of graphene oxide

[0028] Mix 3g of graphite powder with 60-100mL of concentrated sulfuric acid until homogeneous, maintaining the reaction temperature between 0 and 40°C. Slowly add 8-12g of potassium permanganate to the mixture while stirring at a constant speed (2-10h), maintaining the temperature between 5 and 20°C. Continue stirring the mixture for 1-48h. Then, pour the mixture into an ice-water mixing bath to terminate the reaction. Add hydrogen peroxide dropwise to the mixture until no more bubbles are produced. Centrifuge the mixture to obtain graphene oxide, and wash the graphene oxide with dilute hydrochloric acid and deionized water, respectively. Then, redisperse the graphene oxide in deionized water and dialyze to remove any remaining metal ions and acid. Finally, centrifuge the dialyzed dispersion at low speed to remove any unpeeled impurities, and concentrate it at high speed to obtain a monolayer graphene oxide dispersion.

[0029] (2) Preparation of porous redox graphene

[0030] 400 mL of solution with a concentration of 1-5 mg / mL -1 Add 30-60 mL of 30% hydrogen peroxide solution to the graphene oxide dispersion and react at 90-120℃ for 4-10 h. The resulting porous graphene oxide dispersion is then vacuum filtered and washed with deionized water. Finally, the porous graphene oxide dispersion is centrifuged, concentrated, and freeze-dried to obtain porous graphene oxide powder.

[0031] (3) Preparation of porous redox graphene / aramid III composite fibers

[0032] The fiber has a tensile strength of 4.77 GPa, an elastic modulus of 188 GPa, and an elongation at break of 3.78%. The molecular structure of aramid III is as follows:

[0033]

[0034] In the formula, the molar ratio of terephthaloyl chloride (TPC), p-phenylenediamine (PPD), and 2-(4-aminophenyl)-5-aminobenzimidazole (DAPBI) is 1:0.4:0.6, and the polymer solid content of the spinning solution is 4.2 wt%.

[0035] The above-mentioned method for preparing heterocyclic aromatic copolyamide fibers includes the following process steps:

[0036] (a) Preparation of spinning solution for graphene / aramid III

[0037] First, p-phenylenediamine and 2-(4-aminophenyl)-5-aminobenzimidazole are added to the solvent system and stirred uniformly under nitrogen protection until completely dissolved. Then, graphene dispersion is added, the temperature inside the reactor is lowered to 8°C, and terephthaloyl chloride is added in 2-3 portions. After stirring thoroughly for 1-3 hours, the polymerization reaction is terminated, and a homogeneous spinning solution is obtained. The dynamic viscosity of the obtained polymer is 40,000-70,000 centipoise. The solvent system is N'N-dimethylacetamide (DMAc), the chloride salt is lithium chloride (LiCl), the amount of chloride salt is 3.5 wt% of the weight of the solvent used, and the water content of the solvent system is 50 ppm.

[0038] (b) Wet spinning

[0039] The above-mentioned spinning slurry is filtered, vacuum degassed, and then placed in a multi-stage coagulation bath at 0-5℃, washed, dried, and treated at 380-450℃ for 60-180s under a nitrogen atmosphere to obtain graphene / aramid III composite fiber.

[0040] The advantages of this invention are: starting from the design and screening research of graphene, a porous graphene powder is synthesized through a simple and low-cost method, and then the graphene powder is compounded with the aramid III molecular backbone through in-situ low-temperature polycondensation, so that the aramid III molecular chain is tightly bonded to the graphene, thereby effectively enhancing the interaction force between the aramid III molecular chains. The purpose is to provide a complete production method for high-strength and high-modulus graphene / aramid III composite fiber and its continuous and stable high-efficiency spinning process from polymerization to wet spinning, with a complete process system.

[0041] 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.

[0042] Unless otherwise specified, all reagents, materials and instruments used in the following examples and comparative examples are commercially available.

[0043] Example 1

[0044] In a nitrogen-atmospheric reactor, PPD and DAPBI were added to the DMAc solvent system at a molar ratio of TPC:PPD:DAPBI = 1:0.4:0.6. After stirring until PPD and DAPBI were completely dissolved, the system was cooled to 8°C, and a concentration of 0.5 mg / mL was determined. -1 The graphene dispersion was added in situ during the polymerization of aramid III, and stirred for 0.5-1 h. The graphene was a redox porous graphene with a size of 1 μm (e.g., Figure 2 As shown), the number of layers is 2, and the pore size is about 10-20nm (e.g. Figure 3 As shown), the pore density is 0.86 m³. 3 g -1 The first batch of TPC was then added to the system and stirred thoroughly for 1-2 hours. This was followed by adding TPC in 2-4 batches to obtain a homogeneous polymer spinning solution with a dynamic viscosity of 41,000 centipoise. The polymer solids content in the spinning slurry was 4.2 wt%, the LiCl content in the DMAc / LiCl solvent system was 3.5 wt%, and the moisture content was 50 ppm. The specific parameters of this graphene / aramid III composite fiber include: graphene content of 0.01 wt%, tensile strength of 33.28 cN / dtex, elastic modulus of 814.09 cN / dtex, and elongation at break of 3.83%.

[0045] Figure 4 The figure shows a characterization diagram of the porous graphene / aramid III polymer solution prepared in this embodiment, which shows that the aramid III nanofibers pass through the pore structure of the graphene.

[0046] Figure 5 The image shows a SEM image of the graphene / aramid III composite fiber prepared in this embodiment. It can be seen from the image that the introduction of porous redox graphene can make the surface and internal structure of the aramid fiber more compact.

[0047] Example 2

[0048] In a nitrogen-atmospheric reactor, PPD and DAPBI were added to the DMAc solvent system at a molar ratio of TPC:PPD:DAPBI = 1:0.4:0.6. After stirring until PPD and DAPBI were completely dissolved, the system was cooled to 8°C, and a concentration of 2.5 mg / mL was determined. -1 The graphene dispersion was added in situ during the polymerization of aramid III and stirred for 0.5-1 h. The graphene was a redox porous graphene with a size of 1 μm, two layers, and a pore density of 0.86 m³. 3 g -1 The first batch of TPC was then added to the system and stirred thoroughly for 1-2 hours. Subsequent batches of TPC were added in 2-4 batches to obtain a homogeneous polymer spinning solution with a dynamic viscosity of 48,000 centipoise. The polymer solids content in the spinning slurry was 4.2 wt%, the LiCl content in the DMAc / LiCl solvent system was 3.5 wt%, and the moisture content was 50 ppm. The specific parameters of this graphene / aramid III composite fiber include: graphene content of 0.05 wt%, tensile strength of 33.79 cN / dtex, elastic modulus of 858.66 cN / dtex, and elongation at break of 3.89%.

[0049] Example 3

[0050] In a nitrogen-atmospheric reactor, PPD and DAPBI were added to the DMAc solvent system at a molar ratio of TPC:PPD:DAPBI = 1:0.4:0.6. After stirring until PPD and DAPBI were completely dissolved, the system was cooled to 8°C, and a concentration of 2.5 mg / mL was determined. -1 The graphene dispersion was added in situ during the polymerization of aramid III and stirred for 0.5-1 h. The graphene was a redox porous graphene with a size of 1 μm, two layers, and a pore density of 0.86 m³. 3 g -1 The first batch of TPC was then added to the system and stirred thoroughly for 1-2 hours. This was followed by adding TPC in 2-4 batches to obtain a homogeneous polymer spinning solution with a dynamic viscosity of 48,000 centipoise. The polymer solids content in the spinning solution was 4.2 wt%, the LiCl content in the DMAc / LiCl solvent system was 3.5 wt%, and the moisture content was 50 ppm. The specific parameters of this graphene / aramid III composite fiber include: graphene content of 0.075 wt%, tensile strength of 33.18 cN / dtex, elastic modulus of 835.43 cN / dtex, and elongation at break of 3.94%.

[0051] Example 4

[0052] In a nitrogen-atmospheric reactor, PPD and DAPBI were added to the DMAc solvent system at a molar ratio of TPC:PPD:DAPBI = 1:0.4:0.6. After stirring until PPD and DAPBI were completely dissolved, the system was cooled to 8°C, and a concentration of 5.0 mg / mL was determined. -1 The graphene dispersion was added in situ during the polymerization of aramid III and stirred for 0.5-1 h. The graphene was a redox porous graphene with a size of 1 μm, two layers, and a pore density of 0.86 m³. 3 g -1 The first batch of TPC was then added to the system and stirred thoroughly for 1-2 hours. Subsequent batches of TPC were added in 2-4 batches to obtain a homogeneous polymer spinning solution with a dynamic viscosity of 48,000 centipoise. The polymer solids content in the spinning solution was 4.2 wt%, the LiCl content in the DMAc / LiCl solvent system was 3.5 wt%, and the moisture content was 50 ppm. The specific parameters of this graphene / aramid III composite fiber include: graphene content of 1.0 wt%, tensile strength of 31.08 cN / dtex, elastic modulus of 834.55 cN / dtex, and elongation at break of 3.92%.

[0053] Example 5

[0054] In a nitrogen-atmospheric reactor, PPD and DAPBI were added to the DMAc solvent system at a molar ratio of TPC:PPD:DAPBI = 1:0.4:0.6. After stirring until PPD and DAPBI were completely dissolved, the system was cooled to 8°C, and a concentration of 2.5 mg / mL was determined. -1 The graphene dispersion was added in situ during the polymerization of aramid III and stirred for 0.5-1 h. The graphene was a redox porous graphene with a size of 5 μm, 2 layers, and a pore density of 0.86 m³. 3 g -1 The first batch of TPC was then added to the system and stirred thoroughly for 1-2 hours. This process was repeated in 2-4 batches to obtain a homogeneous polymer spinning solution with a dynamic viscosity of 49,000 centipoise. The polymer solids content in the spinning solution was 4.2 wt%, the LiCl content in the DMAc / LiCl solvent system was 3.5 wt%, and the moisture content was 50 ppm.

[0055] The specific parameters of this graphene / aramid III composite fiber include: graphene content of 0.05 wt%, tensile strength of 32.16 cN / dtex, elastic modulus of 831.42 cN / dtex, and elongation at break of 3.89%.

[0056] Example 6

[0057] In a nitrogen-atmospheric reactor, PPD and DAPBI were added to the DMAc solvent system at a molar ratio of TPC:PPD:DAPBI = 1:0.4:0.6. After stirring until PPD and DAPBI were completely dissolved, the system was cooled to 8°C, and a concentration of 2.5 mg / mL was determined. -1 The graphene dispersion was added in situ during the polymerization of aramid III and stirred for 0.5-1 h. The graphene was a redox porous graphene with a size of 2.5 μm, two layers, and a pore density of 0.86 m³. 3 g -1 The first batch of TPC was then added to the system and stirred thoroughly for 1-2 hours. This process was repeated in 2-4 batches to obtain a homogeneous polymer spinning solution with a dynamic viscosity of 49,000 centipoise. The polymer solids content in the spinning solution was 4.2 wt%, the LiCl content in the DMAc / LiCl solvent system was 3.5 wt%, and the moisture content was 50 ppm.

[0058] The specific parameters of this graphene / aramid III composite fiber include: graphene content of 0.05 wt%, tensile strength of 33.05 cN / dtex, elastic modulus of 829.45 cN / dtex, and elongation at break of 3.88%.

[0059] Example 7

[0060] In a nitrogen-atmospheric reactor, PPD and DAPBI were added to the DMAc solvent system at a molar ratio of TPC:PPD:DAPBI = 1:0.4:0.6. After stirring until PPD and DAPBI were completely dissolved, the system was cooled to 8°C, and a concentration of 2.5 mg / mL was determined. -1 The graphene dispersion was added in situ during the polymerization of aramid III and stirred for 0.5-1 h. The graphene was a redox porous graphene with a size of 1 μm, 5 layers, and a pore density of 0.86 m³. 3 g -1 The first batch of TPC was then added to the system and stirred thoroughly for 1-2 hours. This process was repeated in 2-4 batches to obtain a homogeneous polymer spinning solution with a dynamic viscosity of 49,000 centipoise. The polymer solids content in the spinning solution was 4.2 wt%, the LiCl content in the DMAc / LiCl solvent system was 3.5 wt%, and the moisture content was 50 ppm.

[0061] The specific parameters of this graphene / aramid III composite fiber include: graphene content of 0.05 wt%, tensile strength of 33.28 cN / dtex, elastic modulus of 836.17 cN / dtex, and elongation at break of 3.92%.

[0062] Example 8

[0063] In a nitrogen-atmospheric reactor, PPD and DAPBI were added to the DMAc solvent system at a molar ratio of TPC:PPD:DAPBI = 1:0.4:0.6. After stirring until PPD and DAPBI were completely dissolved, the system was cooled to 8°C, and a concentration of 2.5 mg / mL was determined. -1 The graphene dispersion was added in situ during the polymerization of aramid III and stirred for 0.5-1 h. The graphene was a redox porous graphene with a size of 1 μm, 3 layers, and a pore density of 0.86 m³. 3 g -1 The first batch of TPC was then added to the system and stirred thoroughly for 1-2 hours. This process was repeated in 2-4 batches to obtain a homogeneous polymer spinning solution with a dynamic viscosity of 49,000 centipoise. The polymer solids content in the spinning solution was 4.2 wt%, the LiCl content in the DMAc / LiCl solvent system was 3.5 wt%, and the moisture content was 50 ppm.

[0064] The specific parameters of this graphene / aramid III composite fiber include: graphene content of 0.05 wt%, tensile strength of 33.43 cN / dtex, elastic modulus of 831.85 cN / dtex, and elongation at break of 3.94%.

[0065] Comparative Example 1

[0066] In a nitrogen-atmospheric reactor, PPD and DAPBI were added to the DMAc solvent system at a molar ratio of TPC:PPD:DAPBI = 1:0.4:0.6. After stirring until PPD and DAPBI were completely dissolved, the system was cooled to 8°C, and a concentration of 2.5 mg / mL was determined. -1 A graphene dispersion was added in situ during the polymerization of aramid III, and stirred for 0.5-1 h. The graphene was a redox porous graphene with a size of 1 μm, two layers, and a pore density of 0.26 m³. 3 g -1 The first batch of TPC was then added to the system and stirred thoroughly for 1-2 hours. TPC was then added in 2-4 batches to obtain a homogeneous polymer spinning solution with a dynamic viscosity of 45,000 centipoise. The polymer solids content in the spinning slurry was 4.2 wt%, the LiCl content in the DMAc / LiCl solvent system was 3.5 wt%, and the moisture content was 50 ppm. The specific parameters of this graphene / aramid III composite fiber include: graphene content of 0.05 wt%, tensile strength of 29.87 cN / dtex, elastic modulus of 792.67 cN / dtex, and elongation at break of 3.78%.

[0067] Comparative Example 2

[0068] In a nitrogen-atmospheric reactor, PPD and DAPBI were added to the DMAc solvent system at a molar ratio of TPC:PPD:DAPBI = 1:0.4:0.6. After stirring until PPD and DAPBI were completely dissolved, the system was cooled to 8°C, and a concentration of 2.5 mg / mL was determined. -1 The graphene dispersion was added in situ during the polymerization of aramid III and stirred for 0.5-1 h. The graphene was a redox porous graphene with a size of 20 μm, 2 layers, and a pore density of 0.86 m³. 3 g -1 The first batch of TPC was then added to the system and stirred thoroughly for 1-2 hours. This was followed by adding TPC in 2-4 batches to obtain a homogeneous polymer spinning solution with a dynamic viscosity of 45,000 centipoise. The polymer solids content in the spinning slurry was 4.2 wt%, the LiCl content in the DMAcLiCl solvent system was 3.5 wt%, and the moisture content was 50 ppm. Specific parameters of this graphene / aramid III composite fiber included: graphene content of 0.05 wt%, tensile strength of 27.66 cN / dtex, elastic modulus of 788.82 cN / dtex, and elongation at break of 3.79%.

[0069] Comparative Example 3

[0070] In a nitrogen-atmospheric reactor, PPD and DAPBI were added to the DMAc solvent system at a molar ratio of TPC:PPD:DAPBI = 1:0.4:0.6. After stirring until PPD and DAPBI were completely dissolved, the system was cooled to 8°C, and a concentration of 2.5 mg / mL was determined. -1 A graphene dispersion was added in situ during the polymerization of aramid III, and stirred for 0.5-1 h. The graphene was a reduced-oxidation graphene with a size of 1 μm, two layers, and a pore density of 1.6 μm. 3 g -1 The first batch of TPC was then added to the system and stirred thoroughly for 1-2 hours. This was followed by adding TPC in 2-4 batches to obtain a homogeneous polymer spinning solution with a dynamic viscosity of 45,000 centipoise. The polymer solids content in the spinning slurry was 4.2 wt%, the LiCl content in the DMAc / LiCl solvent system was 3.5 wt%, and the moisture content was 50 ppm. Specific parameters of the graphene / aramid III composite fiber included: graphene content of 0.05 wt%, tensile strength of 26.96 cN / dtex, elastic modulus of 778.56 cN / dtex, and elongation at break of 3.74%.

[0071] Comparative Example 4

[0072] In a nitrogen-atmospheric reactor, PPD and DAPBI were added to the DMAc solvent system at a molar ratio of TPC:PPD:DAPBI = 1:0.4:0.6. After stirring until PPD and DAPBI were completely dissolved, the system was cooled to 8°C, and a concentration of 2.5 mg / mL was determined. -1 A graphene dispersion was added in situ during the polymerization of aramid III, and stirred for 0.5-1 h. The graphene was graphene oxide with a size of 1 μm, 2 layers, and a pore density of 0.08 μm. 3 g -1 The first batch of TPC was then added to the system and stirred thoroughly for 1-2 hours. This was followed by adding TPC in 2-4 batches to obtain a homogeneous polymer spinning solution with a dynamic viscosity of 45,000 centipoise. The polymer solids content in the spinning slurry was 4.2 wt%, the LiCl content in the DMAc / LiCl solvent system was 3.5 wt%, and the moisture content was 50 ppm. Specific parameters of the graphene / aramid III composite fiber included: graphene content of 0.05 wt%, tensile strength of 25.36 cN / dtex, elastic modulus of 738.76 cN / dtex, and elongation at break of 3.69%.

[0073] Comparative Example 5

[0074] In a nitrogen-enclosed reactor, PPD and DAPBI were added to the DMAc solvent system at a molar ratio of TPC:PPD:DAPBI = 1:0.4:0.6. After stirring until PPD and DAPBI were completely dissolved, the system was cooled to 8°C. The first batch of TPC was then added to the system and stirred thoroughly for 1-2 hours. Subsequent batches of TPC were added in 2-4 batches, stirring for 0.5-1 hour each. Near the end of the polymerization reaction, a final concentration of 2.5 mg / mL was added. -1 A graphene dispersion, wherein the graphene is a redox porous graphene with a size of 1 μm, two layers, and a pore density of 0.86 m³. 3 g -1 The polymer homogeneous spinning solution with a dynamic viscosity of 47,000 centipoise was obtained by stirring the mixture in the solution for 0.5 h. The polymer solids content in the spinning slurry was 4.2 wt%, the LiCl content in the DMAc / LiCl solvent system was 3.5 wt%, and the moisture content was 50 ppm. The specific properties of the graphene / aramid III composite fiber are as follows: graphene content 0.05 wt%, tensile strength 27.58 cN / dtex, elastic modulus 762.46 cN / dtex, and elongation at break 3.69%.

[0075]

[0076]

[0077] 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 graphene-modified aramid III composite fiber, characterized in that, The composite fiber comprises porous graphene and aramid III polymer, wherein the main chain of the aramid III polymer passes through the pores of the porous graphene, and the content of the porous graphene is 0.01wt%-1wt%.

2. The graphene-modified aramid III composite fiber according to claim 1, characterized in that, The porous graphene has a particle size of 1-5 μm and 2-5 layers.

3. The graphene-modified aramid III composite fiber according to claim 1, characterized in that, The porous graphene has a pore density of 0.08-1.6 m³. 3 g -1 .

4. The graphene-modified aramid III composite fiber according to claim 1, characterized in that, The graphene-modified aramid III composite fiber has a breaking strength of 32-34 cN / dtex, an elastic modulus of 810-900 cN / dtex, and an elongation at break of 3.8-4.2%.

5. A method for preparing graphene-modified aramid III composite fiber according to any one of claims 1-4, characterized in that, include: S1, add the porous redox graphene dispersion to the solution containing the monomers for preparing aramid III polymer, mix evenly, and then allow the monomers to undergo a condensation reaction to form a polymer solution.

6. The method for preparing graphene-modified aramid III composite fiber according to claim 5, characterized in that, Also includes: S2, wet spinning is performed on the polymer solution.

7. The method for preparing graphene-modified aramid III composite fiber according to claim 6, characterized in that, The polymer solution has a solid content of 4.2 wt% and a dynamic viscosity of 40,000-60,000.

Images