Graphdiyne modified aramid iii composite fiber and preparation method thereof

Abstract

The application discloses a graphite diacetylene modified aramid III composite fiber and a preparation method thereof. The graphite diacetylene is added in the process of forming the aramid III polymer. The graphite diacetylene participates in the whole condensation reaction through in-situ addition. The conjugated structure on the surface of the graphite diacetylene nanosheet can be combined with the aramid molecules through van der Waals force, so that the crystallization and orientation of the aramid III molecules are induced, the interaction between the aramid macromolecular chains is enhanced, the internal structural defects of the aramid III are filled, the aramid III is more compact, the compactness of the aramid fiber is improved, and the mechanical properties of the aramid fiber are improved. Meanwhile, the carbon-carbon triple bond functional groups are introduced due to the addition of the graphite diacetylene, so that the function of the aramid III fiber is increased.

Description

Technical Field

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

[0002] Aramid III fiber possesses excellent properties such as high strength, corrosion resistance, creep resistance, and impact resistance, making it widely used in military manufacturing, aerospace, automotive manufacturing, and protective equipment, becoming an indispensable material in people's daily lives. Furthermore, as the application range of aramid fiber expands, its production cost is gradually decreasing. However, because aramid III fiber is a polyamide fiber composed of aromatic heterocyclic rings, its surface functional group activity is relatively low, limiting the methods for modifying it to further enhance its mechanical strength and functionality.

[0003] Graphitic diacetylene is a type of graphitic diacetylene composed of sp and sp 2 Two-dimensional carbon materials, composed of regularly arranged hybrid carbon atoms, possess unique carbon-carbon triple bond (-C≡C-) functional groups, large conjugated systems, and uniform porous structures, as well as high specific surface area, excellent electrical properties, and superior mechanical strength. Graphdiyne can serve as an ideal reinforcing material for aramid III fibers. However, there are currently few reports on the design and process control of graphdiyne composite fiber modification. Therefore, research and process control of graphdiyne-modified aramid III fibers have become urgent problems to be solved. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention provides a graphite-diyne-modified aramid III composite fiber and its preparation method.

[0005] The present invention provides a graphdiyne-modified aramid III composite fiber, the composite fiber comprising graphdiyne and aramid III polymer, wherein the graphdiyne is added during the formation of the aramid III polymer.

[0006] According to one embodiment of the present invention, based on the total mass of the modified aramid III composite fiber as 100%, the amount of graphitic diacetylene used accounts for 0.001%-5wt% of the modified aramid III composite fiber.

[0007] According to another embodiment of the present invention, the graphite diacetylene has a sheet diameter of 200-300 nm.

[0008] According to another embodiment of the present invention, the tensile strength is 30-35 cN / dtex, the elastic modulus is 850-1000 cN / dtex, and the elongation at break is 3.6-4.5%.

[0009] The present invention also provides a method for preparing the above-mentioned graphdiyne-modified aramid III composite fiber, comprising: S1, dispersing graphdiyne in N,N-dimethylacetamide to form a dispersion; S2, adding the dispersion to an N,N-dimethylacetamide solution containing monomers forming aramid III, and performing a polymerization reaction to obtain a polymer solution; and S3, spinning the polymer solution to obtain graphdiyne-modified aramid III composite fiber.

[0010] According to one embodiment of the present invention, the mass content of the graphitic diacetylene in the dispersion is 0.001%-5wt%.

[0011] This invention relates to graphite bis-acetylene-modified aramid III composite fibers. By adding the graphite bis-acetylene in situ, the graphite bis-acetylene participates in the entire polycondensation reaction. The conjugated structure on the surface of the graphite bis-acetylene nanosheets can tightly bind with aramid molecules through van der Waals forces, inducing the crystallization and orientation of aramid III molecules, enhancing the inter-chain forces of aramid polymers, and filling internal structural defects in aramid III, making aramid III denser and improving the density of aramid fibers, thereby enhancing the mechanical properties of aramid fibers.

[0012] This invention discloses a method for preparing graphdiyne-modified aramid III composite fibers. Utilizing the excellent dispersibility of graphdiyne in DMAc (N,N-dimethylacetamide), the graphdiyne is first uniformly dispersed in DMAc to obtain a homogeneous and stable graphdiyne dispersion. Through in-situ addition, the graphdiyne participates in the entire polycondensation reaction, resulting in more uniform dispersion. During polymerization, the graphdiyne not only enhances the intermolecular forces of aramid III molecules, inducing crystallization and orientation, but also fills internal structural defects, making the aramid III more compact. The uniformly dispersed graphdiyne leads to more stable composite fiber properties. Graphdiyne modification not only improves the mechanical properties of aramid III fibers but also introduces carbon-carbon triple bond functional groups, thereby enhancing the functionality of the aramid III fibers. Attached Figure Description

[0013] Figure 1 This is a photograph of the graphite diacetylene DMAc dispersion from Example 1.

[0014] Figure 2 The image shows a scanning electron microscope (SEM) image of the graphite-diyne-modified aramid III composite fiber prepared in Example 1.

[0015] Figure 3 XRD patterns of graphite-modified aramid III composite fiber with graphite-diyne addition of 0.1 wt% prepared in Example 1 and pure aramid fiber in Comparative Example 1. Detailed Implementation

[0016] The present invention will now be described in detail with reference to specific embodiments.

[0017] This invention relates to graphdiyne-modified aramid III composite fibers. The composite fibers comprise graphdiyne and an aramid III polymer, with the graphdiyne added during the formation of the aramid III polymer. This invention uses graphdiyne as a reinforcement for the aramid III fibers. Through in-situ polymerization, the interaction forces between the graphdiyne and aramid III molecular chains induce further crystallization and orientation of the aramid III, while also densifying the aramid III fibers. Graphdiyne modification not only improves the mechanical properties of the aramid III fibers but also introduces carbon-carbon triple bond functional groups, thereby enhancing the functionality of the aramid III fibers.

[0018] In an optional embodiment, based on the total mass of the modified aramid III composite fiber (100%), the amount of graphdiyne is 0.001 wt% to 5 wt% of the modified aramid III composite fiber. If the graphdiyne content is too low (below 0.001 wt%), the reinforcing effect is minimal; if the content is greater than 5 wt%, the dispersibility is poor, affecting the fiber performance. Preferably, the amount of graphdiyne is 0.05 wt% to 0.1 wt% of the modified aramid III composite fiber.

[0019] In an optional embodiment, the graphitic diacetylene has a sheet diameter of 200–300 nm.

[0020] In an optional embodiment, the breaking strength is 30-35 cN / dtex, the elastic modulus is 850-1000 cN / dtex, and the elongation at break is 3.6-4.5%.

[0021] The present invention also provides a method for preparing the above-mentioned graphite bis-yne modified aramid III composite fiber, comprising: S1, dispersing graphite bis-yne in N,N-dimethylacetamide to form a dispersion; S2, adding the dispersion to an N,N-dimethylacetamide solution containing monomers forming aramid III, and performing a polymerization reaction to obtain a polymer solution; and S3, spinning the polymer solution to obtain graphite bis-yne modified aramid III composite fiber.

[0022] Specifically, in step S1, graphdiyne nanosheets are dispersed in DMAc. A uniform and stable graphdiyne dispersion can be obtained by ultrasonic treatment for 0.1-2 hours. The mass fraction of graphdiyne is 0.001-5 wt%.

[0023] In step S2, a graphdiyne / aramid III composite fiber polymerization solution is prepared. A specific example is as follows: LiCl co-solvent, p-phenylenediamine (PPD), and 2-(4-aminophenyl)-5-aminobenzimidazole (DAPBI) and other polymerization monomers are added to an ultra-dry DMAc solution and stirred for 30 minutes under inert gas protection until completely dissolved. The graphdiyne dispersion prepared in step S1 is added before the polymerization reaction to ensure graphdiyne participates in the entire polymerization process. Once the reactor temperature drops to 0-8°C, the first batch of terephthaloyl chloride (TPC) is added and stirred for 0.5-1 hour. Then, TPC is added in 2-5 batches, and the mixture is stirred thoroughly for 1-2 hours to obtain the graphdiyne / aramid III polymerization solution. Furthermore, by adjusting the amount of graphdiyne added (0.001%-5%), polymerization solutions with different graphdiyne contents are obtained. The amount of LiCl used was 3.5 wt%, the molar ratio of TPC, PPD, and DAPBI was 1:0.4:0.6, and the polymer solid content was 4.2 wt%. The chemical formula for the polymerization process in this step is shown below:

[0024]

[0025] In step S3, the polymerization solution is spun to obtain graphitized diathylene-modified aramid III composite fibers. A specific example is as follows: The above graphitized diathylene / aramid III polymerization solution is subjected to vacuum degassing, followed by negative stretching, multi-stage coagulation bath, water washing, and drying. It is then placed in a heat treatment channel at 380-450℃ and treated under nitrogen for 1-3 minutes. Finally, it is wound into filaments to obtain graphitized diathylene / aramid III composite fibers with a breaking strength of 30-35 cN / dtex, an elastic modulus of 850-1000 cN / dtex, and a breaking elongation of 3.6-4.5%.

[0026] In an optional embodiment, the content of graphitic diacetylene in the dispersion is 0.001%-5wt%.

[0027] 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.

[0028] Unless otherwise specified, all reagents, materials and instruments used in the following examples and comparative examples are commercially available.

[0029] 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.

[0030] Example 1

[0031] S1: A certain mass of graphitic diacetylene powder (particle size 200-300 nm) was dispersed in DMAc and ultrasonically treated for 30 min under anhydrous and inert atmosphere to obtain a uniform and stable dispersion. The concentration of graphitic diacetylene powder in the dispersion was 0.73 mg / mL. A photograph of the obtained dispersion is shown below. Figure 1 As shown.

[0032] S2: LiCl co-solvent, p-phenylenediamine (PPD), and 2-(4-aminophenyl)-5-aminobenzimidazole (DAPBI) monomers were added to ultra-dry DMAc and stirred for 30 min under inert gas protection until completely dissolved. The graphdiyne dispersion prepared in the first stage was added before the polymerization reaction to ensure the graphdiyne participated in the entire polymerization process. After the reactor temperature dropped to 0-8℃, the first batch of terephthaloyl chloride (TPC) was added and stirred for 0.5-1 h. Then, TPC was added in 2-5 batches, and stirred thoroughly for 1-2 h to obtain the graphdiyne / aramid III polymerization solution. Furthermore, by adjusting the amount of graphdiyne added (0.001wt%-5wt%), polymerization solutions with different graphdiyne contents were obtained. The LiCl dosage was 3.5wt%, the molar ratio of TPC, PPD, and DAPBI was 1:0.4:0.6, and the polymer solid content was 4.2wt%.

[0033] S3: The obtained polymerization solution was subjected to a series of steps including primary coagulation bath, secondary coagulation bath, washing, drying, hot stretching, oiling, and winding. The negative stretching ratio in the primary coagulation bath was -0.626, the stretching ratio in the secondary coagulation bath was 2.05, and there was no stretching ratio during washing, while the hot stretching ratio was 1.0125. These conventional spinning parameters were used to prepare modified aramid III fibers. Finally, the mechanical properties of the fibers with different graphitic diacetylene contents were tested, and the results are shown in Table 1.

[0034] Comparative Example 1

[0035] Except for the absence of graphitic diacetylene, the other steps were the same as in Example 1. The test results of the obtained fiber side are shown in Table 1.

[0036] Table 1

[0037]

[0038] As can be seen from Table 1, the addition of graphylene can improve the mechanical properties of composite aramid fibers.

[0039] from Figure 1 As can be seen, graphitic diacetylene powder can be stably dispersed in DMAc solution. Figure 2 Electron micrograph of graphite-diyne modified fibers with an addition amount of 0.1 wt%. From Figure 2 As can be seen, the surface of the composite fiber is smooth.

[0040] from Figure 3 As can be seen, adding graphdiyne powder in situ to the polymerization system of aramid III can induce crystallization and orientation during the polymerization process, resulting in fibers with better crystallinity and orientation compared to aramid III without graphdiyne modification.

[0041] In summary, based on the mechanical properties and XRD patterns of the fibers prepared in Comparative Example 1 and Comparative Example 1, it can be seen that the mechanical properties of the fibers modified with graphite bis-acetylene are improved.

[0042] 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 graphite-diyne-modified aramid III composite fiber, characterized in that, The composite fiber comprises graphdiyne and aramid III polymer, wherein the graphdiyne is added during the formation of the aramid III polymer; Based on the total mass of the modified aramid III composite fiber as 100%, the amount of graphite diacetylene used accounts for 0.001%-5 wt% of the modified aramid III composite fiber.

2. The graphite-diyne-modified aramid III composite fiber according to claim 1, characterized in that, The amount of graphitic diacetylene used accounts for 0.05wt%-0.1wt% of the modified aramid III composite fiber.

3. The graphite-diyne-modified aramid III composite fiber according to claim 1, characterized in that, The graphitic diacetylene has a sheet diameter of 200~300 nm.

4. The graphite-diyne-modified aramid III composite fiber according to claim 1, characterized in that, The modified aramid III composite fiber has a breaking strength of 30-35 cN / dtex, an elastic modulus of 850-1000 cN / dtex, and an elongation at break of 3.6-4.5%.

5. A method for preparing graphite-diyne-modified aramid III composite fiber according to any one of claims 1-4, characterized in that, include: S1, Graphdiyne is dispersed in N,N-dimethylacetamide to form a dispersion; S2, the dispersion is added to an N,N-dimethylacetamide solution containing monomers that form aramid III, and a polymerization reaction is carried out to obtain a polymer solution; and S3, the polymer solution is spun to obtain graphite-diyne modified aramid III composite fiber.

6. The preparation method according to claim 5, characterized in that, The mass content of the graphitic diacetylene in the dispersion is 0.001%-5wt%.

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