Acyl chloride porous graphene modified aramid iii composite fiber and preparation method thereof

Abstract

The application discloses a modified aramid III composite fiber and a preparation method thereof. The composite fiber comprises porous graphene and aramid III polymer, and the aramid III polymer and the acyl chloride graphene are connected in the form of a chemical covalent bond. The graphene is connected with the aramid III polymer through a covalent bond, so that the graphene not only can enhance the interaction force between aramid III molecular chains, but also can fill internal structural defects of the aramid III, and finally has an enhancing effect on the aramid III fiber.

Description

TECHNICAL FIELD

[0001] The present application relates to aramid fiber technology field, more particularly to modified aramid III composite fiber and a preparation method thereof. BACKGROUND

[0002] Aramid III fiber is a kind of para-aromatic polyamide fiber with heterocyclic structure in the main chain, which has excellent physical and chemical properties such as light weight, high strength, good impact resistance, high temperature resistance and corrosion resistance. Theoretically, the strength and modulus of aramid III can reach more than 30 GPa and 182 MPa respectively, but the tensile strength of heterocyclic aramid fiber is far lower than its theoretical value. At present, the research on improving the mechanical properties of aramid III fiber mainly focuses on two directions of structure modification and surface modification. In the structure modification, the main means is to introduce new flexible groups such as ether bond and silicon bond into the molecular main chain, which can effectively improve the processability of the fiber, and the mechanical properties of the fiber can be improved by increasing the molecular chain orientation degree. In the surface modification, methods such as plasma treatment, coupling agent and surface coating are often used to improve the affinity between the fiber and the matrix, so as to enhance the overall performance of the composite material. However, most of the modification methods at present have little effect on the improvement of the mechanical properties of aramid III yarn, or the process is difficult to realize large-scale operation. Therefore, new ideas need to be developed for the toughening research of aramid III fiber. SUMMARY

[0003] In order to improve the mechanical properties of aramid III, the present application provides a modified aramid III and a preparation method thereof.

[0004] In one aspect, the present application provides a modified aramid III composite fiber, which comprises porous graphene and aramid III polymer, and the aramid III polymer and the acyl chloride graphene are connected by chemical covalent bond.

[0005] According to an embodiment of the present application, the particle size of the porous graphene is 500 nm-2 μm, and the layer number is 3-5 layers.

[0006] According to another embodiment of the present application, the content of the porous graphene is 0.01wt%-0.5wt%.

[0007] According to another embodiment of the present application, the pore density of the porous graphene is 0.6-1.26 m 3 g -1 .

[0008] According to another embodiment of the present application, the chlorine content of the porous graphene is 0.5-3.52 atom%.

[0009] According to another embodiment of the present application, the covalent bond is amide bond.

[0010] According to another embodiment of the present application, the graphene modified aramid III composite fiber has a breaking strength of 33-35 cN / dtex, an elastic modulus of 800-900 cN / dtex, and an elongation at break of 3.9-4.1%.

[0011] In another aspect, the present application provides a preparation method of the modified aramid III composite fiber, comprising: S1, dispersing porous graphene modified with an acyl chloride bond in N,N dimethylacetamide to form a first dispersion liquid with uniform dispersion; and S2, adding the first dispersion liquid to a polymerization process of forming the aramid III polymer to perform polymerization reaction to form a polymerization liquid.

[0012] According to an embodiment of the present application, the preparation method further comprises: S3, performing wet spinning on the polymerization liquid.

[0013] According to an embodiment of the present application, the concentration of the porous graphene in the first dispersion liquid is 0.01-50 mg / mL. -1 .

[0014] The small-size graphene obtained after acyl chloride treatment can not only enhance the interaction between aramid III molecular chains, but also fill the internal structural defects of aramid III, ultimately achieving the effect of reinforcing aramid III fiber. The preparation process of the entire small-size acyl chloride graphene powder is simple, and the cost is very low, which can be used for mass production. BRIEF DESCRIPTION OF DRAWINGS

[0015] Figure 1 Figure 1 is a synthesis diagram of acyl chloride small-size porous graphene.

[0016] Figure 2 Figure 2 is a characterization diagram of acyl chloride small-size porous graphene in Example 1.

[0017] Figure 3 Figure 3 is a schematic diagram of in-situ polymerization and preparation of acyl chloride small-size porous graphene / aramid III in Example 1. DETAILED DESCRIPTION

[0018] The present application will be described in detail below in conjunction with specific embodiments.

[0019] The modified aramid III composite fiber of the present application comprises porous graphene and aramid III polymer, and the aramid III polymer and the acyl chloride graphene are connected in the form of chemical covalent bond.

[0020] In an optional embodiment, the porous graphene has a particle size of 500 nm to 2 μm and a layer number of 3 to 5. A person skilled in the art can select a specific particle size and layer number according to actual needs, for example, but not limited to, a particle size of 500 nm, 800 nm, 1 μm, 1.5 μm, 2 μm, and a layer number of 3, 4, 5.

[0021] In an optional embodiment, the content of the porous graphene is 0.01 wt% to 0.5 wt%. If the content of the porous graphene is too low (less than 0.01 wt%), the enhancement effect is not great; if the content is greater than 0.5 wt%, the dispersibility is poor, affecting the performance of the fiber.

[0022] In an optional embodiment, the porous graphene has a pore density of 0.6 to 1.26 m 3 g -1 In the present patent, the "pore density of the porous graphene" is the total pore volume obtained by isothermal adsorption and desorption testing of graphene powder by a specific surface area tester. When the pore density is less than 0.6 m 3 g -1 , the performance of the fiber is not greatly improved; when the pore density is greater than 1.26 m 3 g -1 , the intrinsic structure of the graphene is severely damaged and cannot play a reinforcing role. The porous graphene can be obtained by air reduction method, and of course can also be obtained by other methods.

[0023] In an optional embodiment, the content of chlorine in the porous graphene is 0.5 to 3.52 atom%.

[0024] In an optional embodiment, the covalent bond is an amide bond.

[0025] In an optional embodiment, the graphene-modified aramid III composite fiber has a breaking strength of 33 to 35 cN / dtex, an elastic modulus of 800 to 900 cN / dtex, and an elongation at break of 3.9 to 4.1%.

[0026] The above method for preparing the modified aramid III composite fiber comprises: S1, dispersing the porous graphene modified with acyl chloride on the surface in N,N-dimethylacetamide to form a first dispersion liquid with uniform dispersion; and S2, adding the first dispersion liquid to the polymerization process to form a polymerization liquid.

[0027] In an optional embodiment, the method further comprises: S3, wet spinning the polymerization liquid.

[0028] In an optional embodiment, the concentration of the porous graphene in the first dispersion liquid is 0.01 to 50 mg mL -1 .

[0029] The preparation method of the present application can first obtain porous redox graphene by air reduction method, then obtain small-size porous graphene by homogenizing pulverization method, and finally obtain small-size acyl chloride porous graphene by acyl chloride modification treatment. The graphene can be uniformly dispersed in organic solvent N, N-dimethylacetamide (DMAc), and chemically bonded with -NH2 in the polymer monomer, thereby enhancing the intermolecular force of aramid III molecules, forming a graphene / aramid composite with stable chemical structure. In addition, the small-size graphene can not only be highly dispersed in the organic solvent, but also effectively fill the internal structural defects of aramid fibers, so that the aramid polymer chains become more dense and ordered, and can induce better crystallization and orientation of aramid molecules, thereby comprehensively improving the mechanical properties of the composite fiber.

[0030] The present application will be explained below in combination with Figure 1 and specific embodiments, but those skilled in the art can understand that the present application is not intended to be limited to this specific embodiment.

[0031] (1) Preparation of porous redox graphene

[0032] First, graphene oxide (GO) is prepared by Hummers' method. Then, the GO is calcined at 300-500°C under air atmosphere for 10-60 min to obtain porous redox graphene.

[0033] (2) Preparation of small-size porous redox graphene

[0034] The graphene obtained in step (1) is homogenously pulverized by a homogenizing pulverizer under high temperature and low pressure for 1-4 h to obtain small-size porous graphene.

[0035] (3) Preparation of acyl chloride small-size porous graphene and its dispersion liquid

[0036] The graphene powder obtained in step (2) is dispersed in thionyl chloride, and ultrasonically treated at room temperature for 1-2 h to prepare a stable dispersion liquid. A certain amount of dimethylformamide is added dropwise to the dispersion liquid, and refluxed at 80°C under N2 atmosphere for 10-24 h. The obtained product is treated by repeated centrifugation, filtration and washing with tetrahydrofuran, and then vacuum dried to obtain acyl chloride small-size graphene. The graphene is dispersed in DMAc and ultrasonically treated for 1-2 h to obtain a uniform and stable graphene dispersion liquid, wherein the mass fraction of graphene is 0.001-10%.

[0037] (4) In-situ polymerization of graphene / aramid III and preparation of composite fiber

[0038] LiCl, p-phenylenediamine (PPD), 2-(4-aminophenyl)-5-aminobenzimidazole (DAPBI) were added into DMAc and stirred until completely dissolved under nitrogen protection. The graphene dispersion prepared in (3) was added before the polymerization reaction to make graphene participate in the whole polymerization process. When the temperature of the reactor dropped to 0-8℃, the first batch of terephthalyl chloride (TPC) was added, and after stirring for 0.5-1h, the TPC was added in 2-5 batches, and stirred for 1-2h to obtain a graphene / aramid III polymerization solution. In addition, by adjusting the amount of graphene added (0.001%-10%), a polymerization solution with different graphene contents was obtained. Among them, the amount of LiCl is 3.5wt%, the molar ratio of TPC, PPD and DAPBI is 1:0.4:0.6, and the solid content of the polymer is 4.2wt%. The reaction chemical formula of the aramid III polymerization solution preparation process is:

[0039]

[0040] The graphene / aramid polymerization solution was then vacuum degassed, and then subjected to negative stretching, multi-stage coagulation bath, washing, drying, and then entering a heat treatment channel at 380-450℃ for 1-5min under a nitrogen atmosphere, and finally wound into a graphene / aramid III composite fiber with a breaking strength of 33-35cN / dtex, an elongation at break of 4.0%-4.5%, and an elastic modulus of 800-1000cN / dtex.

[0041] As a further improvement of the present application, the graphene dispersion can be any one or a mixture of several acyl chloride graphene of different sizes in any proportion.

[0042] The preparation method of the present application can obtain porous redox graphene by a simple air reduction method, and then a series of graphene with different sizes is obtained by homogenizing and crushing, and finally acyl chloride porous redox graphene is obtained by acyl chloride modification treatment. The small size graphene powder has good dispersibility in DMAc. The small size graphene obtained after acyl chloride treatment not only can enhance the interaction between the molecular chains of aramid III, but also can fill the internal structural defects of aramid III, and finally has a reinforcing effect on aramid III fiber. The whole preparation process of small size acyl chloride graphene powder is simple and the cost is very low, which can be used for mass production.

[0043] The present application will be further described by specific examples. However, these examples are merely exemplary and do not constitute any limitation on the scope of protection of the present application.

[0044] In the following examples and comparative examples, the reagents, materials and instruments used are commercially available unless otherwise specified.

[0045] Example 1

[0046] A low-cost commercial graphene oxide (GO) was used as raw material, which was calcined at 400℃ for 5 min in a muffle furnace to obtain partially reduced graphene. It was dispersed in deionized water and ultrasonically dispersed for 30 min to obtain a uniform and stable graphene aqueous solution. Then it was transferred to a homogenizer and subjected to high-pressure and low-temperature pulverization treatment at a power of 1500 W for 0.5 h, 1 h, 2 h and 3 h to obtain graphene aqueous solutions with different sizes. Then it was subjected to freeze-drying treatment to obtain porous reduced graphene powders with different sizes.

[0047] Take the above-mentioned porous reduced graphene with a size of 500 nm, 3 layers, a chlorine content of 3.52 atom%, and a pore density of 1.26 m 3 g -1 2 g was added to 160 ml of dichlorosulfide (SOCl2) and 10 mL of dimethylformamide (DMF), then ultrasonically dispersed for 30 min, and then subjected to reflux reaction at 80℃ under N2 atmosphere for 24 h. The obtained product was subjected to repeated centrifugation, filtration and washing with tetrahydrofuran, and then subjected to vacuum drying treatment to obtain acyl chloride modified small-size graphene.

[0048] Figure 2 The characterization graph of the prepared acyl chloride modified small-size porous graphene is shown in the figure a. It is shown that the C content of the graphene after acyl chloride modification is 85.35%, the oxygen content is 11.13%, and the chlorine content is 3.52%, indicating that the carboxyl groups in the partially reduced graphene will undergo acyl chloride reaction with dichlorosulfide to form acyl chloride graphene, i.e. the acyl chloride groups exist in the form of chemical bonds in the porous graphene. Figure b further shows that the acyl chloride graphene mainly exists in the form of C-C, C=O and C-Cl bonds, thereby reflecting that the acyl chloride bond is contained in the porous graphene. In the in-situ polymerization process of the acyl chloride graphene and aramid III, the acyl chloride groups contained in the graphene can form covalent bonds with the amino groups in the p-phenylenediamine through chemical bond interaction.

[0049] Figure 3 The in-situ polymerization of acyl chloride modified small-size porous graphene / aramid III and its preparation schematic diagram are shown in the figure. The specific steps are as follows: a certain amount of the graphene powder was dispersed in DMAc to obtain a graphene dispersion liquid with a concentration of 0.5 mg mL -1 . The graphene dispersion liquid was added in-situ in the aramid III polymerization process, and then graphene / aramid III composite fibers were prepared by spinning. The graphene content was 0.05 wt%, the breaking strength was 35.03 cN / dTex, the tensile modulus was 900.65 cN / dTex, and the breaking elongation was 4.02%.

[0050] Example 2

[0051] Porous redox graphene with 2g size of 500nm, 3 layers of layer, 3.52 atom% of chlorine content, 1.26m 3 g -1 of pore density was added into 160ml of thionyl chloride (SOCl2) and 10mL of dimethylformamide, then ultrasonic dispersion for 30min, 80℃ reflux reaction under N2 atmosphere for 24h, the obtained product was treated by repeated centrifugation, filtration, washing with tetrahydrofuran, and then vacuum drying to obtain acyl chloride large size graphene. A certain amount of graphene powder was dispersed in DMAc to obtain a graphene dispersion liquid with a concentration of 1.0mg mL -1 . The graphene dispersion liquid was added in situ during the polymerization of aramid III, and then the graphene / aramid III composite fiber was prepared by spinning, wherein the graphene content was 0.1wt%, the breaking strength was 34.18cN / dTex, the tensile modulus was measured to be 856.55cN / dTex, and the elongation at break was 3.93%.

[0052] Example 3

[0053] Porous redox graphene with 2g size of 500nm, 3 layers of layer, 3.52 atom% of chlorine content, 1.26m 3 g -1 of pore density was added into 160ml of thionyl chloride (SOCl2) and 10mL of dimethylformamide, then ultrasonic dispersion for 30min, 80℃ reflux reaction under N2 atmosphere for 24h, the obtained product was treated by repeated centrifugation, filtration, washing with tetrahydrofuran, and then vacuum drying to obtain acyl chloride large size graphene. A certain amount of graphene powder was dispersed in DMAc to obtain a graphene dispersion liquid with a concentration of 1.0mg mL -1 . The graphene dispersion liquid was added in situ during the polymerization of aramid III, and then the graphene / aramid III composite fiber was prepared by spinning, wherein the graphene content was 0.1wt%, the breaking strength was 34.18cN / dTex, the tensile modulus was measured to be 856.55cN / dTex, and the elongation at break was 3.93%.

[0054] Example 4

[0055] Porous redox graphene with 2g size of 500nm, 3 layers of layer, 3.52 atom% of chlorine content, 1.26m 3 g -1Porous redox graphene was added to 160 mL of sulfoxide (SOCl2) and 10 mL of dimethylformamide, then ultrasonically dispersed for 30 min, and refluxed at 80 °C for 24 h under N2 atmosphere. The resulting product was repeatedly centrifuged, filtered, washed, and then vacuum dried to obtain acyl chloride large-size graphene. A certain amount of this graphene powder was dispersed in DMAc, and the resulting graphene dispersion concentration was 0.5 mg / mL. -1 Graphene dispersion was added in situ during the polymerization of aramid III, and then graphene / aramid III composite fibers were prepared by spinning. The graphene content was 0.05 wt%, and the tensile strength was 32.56 cN / dTex, the tensile modulus was 834.36 cN / dTex, and the elongation at break was 3.85%.

[0056] Example 5

[0057] 2g of a sample with a size of 500nm, 5 layers, a chlorine content of 3.52atom%, and a pore density of 1.26m³ was collected. 3 g -1 Porous redox graphene was added to 160 mL of sulfoxide (SOCl2) and 10 mL of dimethylformamide, then ultrasonically dispersed for 30 min, and refluxed at 80 °C for 24 h under N2 atmosphere. The resulting product was repeatedly centrifuged, filtered, washed, and then vacuum dried to obtain acyl chloride large-size graphene. A certain amount of this graphene powder was dispersed in DMAc, and the resulting graphene dispersion concentration was 0.5 mg / mL. -1 Graphene dispersion was added in situ during the polymerization of aramid III, and then graphene / aramid III composite fibers were prepared by spinning. The graphene content was 0.05 wt%, and the tensile strength was 33.78 cN / dTex, the tensile modulus was 856.84 cN / dTex, and the elongation at break was 3.98%.

[0058] Example 6

[0059] 2g of a sample with a size of 500nm, 3 layers, a chlorine content of 3.52atom%, and a pore density of 1.26m was collected. 3 g -1 Porous redox graphene was added to 160 mL of sulfoxide (SOCl2) and 10 mL of dimethylformamide, then ultrasonically dispersed for 30 min, and refluxed at 80 °C for 24 h under N2 atmosphere. The resulting product was repeatedly centrifuged, filtered, washed, and then vacuum dried to obtain acyl chloride large-size graphene. A certain amount of this graphene powder was dispersed in DMAc, and the resulting graphene dispersion concentration was 5 mg / mL. -1Graphene dispersion was added in situ during the polymerization of aramid III, and then graphene / aramid III composite fibers were prepared by spinning. The graphene content was 0.5 wt%, and the tensile strength was 32.32 cN / dTex, the tensile modulus was 789.12 cN / dTex, and the elongation at break was 3.88%.

[0060] Example 7

[0061] 2g of a sample with a size of 500nm, 3 layers, a chlorine content of 0.5atom%, and a pore density of 1.26m³ was collected. 3 g -1 Porous redox graphene was added to 160 mL of sulfoxide (SOCl2) and 10 mL of dimethylformamide, then ultrasonically dispersed for 30 min, and refluxed at 80 °C for 24 h under N2 atmosphere. The resulting product was repeatedly centrifuged, filtered, washed, and then vacuum dried to obtain acyl chloride large-size graphene. A certain amount of this graphene powder was dispersed in DMAc, and the resulting graphene dispersion concentration was 0.5 mg / mL. -1 Graphene dispersion was added in situ during the polymerization of aramid III, and then graphene / aramid III composite fibers were prepared by spinning. The graphene content was 0.05 wt%, and the tensile strength was 32.86 cN / dTex, the tensile modulus was 815.16 cN / dTex, and the elongation at break was 3.92%.

[0062] Example 8

[0063] 2g of a sample with a size of 500nm, 3 layers, a chlorine content of 2atom%, and a pore density of 1.26m was collected. 3 g -1 Porous redox graphene was added to 160 mL of sulfoxide (SOCl2) and 10 mL of dimethylformamide, then ultrasonically dispersed for 30 min, and refluxed at 80 °C for 24 h under N2 atmosphere. The resulting product was repeatedly centrifuged, filtered, washed, and then vacuum dried to obtain acyl chloride large-size graphene. A certain amount of this graphene powder was dispersed in DMAc, and the resulting graphene dispersion concentration was 0.5 mg / mL. -1 Graphene dispersion was added in situ during the polymerization of aramid III, and then graphene / aramid III composite fibers were prepared by spinning. The graphene content was 0.05 wt%, and the tensile strength was 33.96 cN / dTex, the tensile modulus was 845.52 cN / dTex, and the elongation at break was 3.98%.

[0064] Example 9

[0065] of 3.52 atom%, pore density of 1.26 m 3 g -1 The porous redox graphene of 2 g in size of 20 pm, 3 layers in layer number, 3.52 atom% in chlorine content, and 1.26 m -1 g 3 The porous redox graphene of 2 g in size of 20 pm, 3 layers in layer number, 3.52 atom% in chlorine content, and 1.26 m -1 The porous redox graphene of 2 g in size of 20 pm, 3 layers in layer number, 3.52 atom% in chlorine content, and 1.26 m -1 The porous redox graphene of 2 g in size of 20 pm, 3 layers in layer number, 3.52 atom% in chlorine content, and 1.26 m 3 The porous redox graphene of 2 g in size of 20 pm, 3 layers in layer number, 3.52 atom% in chlorine content, and 1.26 m -1 The porous redox graphene of 2 g in size of 20 pm, 3 layers in layer number, 3.52 atom% in chlorine content, and 1.26 m

[0066] Comparative Example 1

[0067] The porous redox graphene of 2 g in size of 20 pm, 3 layers in layer number, 3.52 atom% in chlorine content, and 1.26 m 3 The porous redox graphene of 2 g in size of 20 pm, 3 layers in layer number, 3.52 atom% in chlorine content, and 1.26 m -1 The porous redox graphene of 2 g in size of 20 pm, 3 layers in layer number, 3.52 atom% in chlorine content, and 1.26 m -1 The porous redox graphene of 2 g in size of 20 pm, 3 layers in layer number, 3.52 atom% in chlorine content, and 1.26 m 3 The porous redox graphene of 2 g in size of 20 pm, 3 layers in layer number, 3.52 atom% in chlorine content, and 1.26 m -1 The porous redox graphene of 2 g in size of 20 pm, 3 layers in layer number, 3.52 atom% in chlorine content, and 1.26 m

[0068] Comparative Example 2

[0069] The porous redox graphene of 2 g in size of 20 pm, 3 layers in layer number, 3.52 atom% in chlorine content, and 1.26 m 3 The porous redox graphene of 2 g in size of 20 pm, 3 layers in layer number, 3.52 atom% in chlorine content, and 1.26 m -1The obtained product was treated by repeated centrifugation, filtration, washing with tetrahydrofuran, and then vacuum drying to obtain acyl chloride large-size graphene. A certain amount of the graphene powder was dispersed in DMAc to obtain a graphene dispersion liquid with a concentration of 0.5 mg / mL. -1 The graphene dispersion liquid was added in-situ during the polymerization of aramid III to obtain a graphene / aramid polymerization liquid, and then a graphene / aramid III composite fiber was prepared by spinning, wherein the graphene content was 0.05 wt%, the breaking strength was 30.96 cN / dTex, the tensile modulus was 816.83 cN / dTex, and the breaking elongation was 3.86%.

[0070] Comparative Example 3

[0071] A 2 g of porous redox graphene powder with a size of 5 μm, a layer number of 3, a chlorine content of 3.52 atom%, and a pore density of 0.6 m 3 g -1 was added to 160 ml of dichlorosulfide (SOCl2) and 10 mL of dimethylformamide, then ultrasonic dispersion was performed for 30 min, and the obtained product was treated by repeated centrifugation, filtration, washing with tetrahydrofuran, and then vacuum drying to obtain acyl chloride large-size graphene. A certain amount of the graphene powder was dispersed in DMAc to obtain a graphene dispersion liquid with a concentration of 0.5 mg / mL. -1 The graphene dispersion liquid was added at the end of the polymerization reaction of aramid III to obtain a graphene / aramid polymerization liquid, and then a graphene / aramid III composite fiber was prepared by spinning, wherein the graphene content was 0.05 wt%, the breaking strength was 25.86 cN / dTex, the tensile modulus was 766.98 cN / dTex, and the breaking elongation was 3.6%.

[0072] Comparative Example 4

[0073] A 2 g of porous redox graphene powder with a size of 5 μm, a layer number of 3, a chlorine content of 3.52 atom%, and a pore density of 0.6 m 3 g -1 was added to 160 ml of dichlorosulfide (SOCl2) and 10 mL of dimethylformamide, then ultrasonic dispersion was performed for 30 min, and the obtained product was treated by repeated centrifugation, filtration, washing with tetrahydrofuran, and then vacuum drying to obtain acyl chloride large-size graphene. A certain amount of the graphene powder was dispersed in DMAc to obtain a graphene dispersion liquid with a concentration of 0.5 mg / mL. -1 The graphene dispersion liquid was added in-situ during the polymerization of aramid III to obtain a graphene / aramid polymerization liquid, and then a graphene / aramid III composite fiber was prepared by spinning, wherein the graphene content was 0.05 wt%, the breaking strength was 30.96 cN / dTex, the tensile modulus was 816.83 cN / dTex, and the breaking elongation was 3.86%.

[0074] Comparative Example 5

[0075] 2 g of porous redox graphene powder with a size of 20 μm, 3 layers, a chlorine content of 0 atom%, and a pore density of 1.02 m 3 g -1 was dispersed in DMAc to obtain a graphene dispersion liquid with a concentration of 0.5 mg mL -1 . The graphene dispersion liquid was added in situ during the polymerization of aramid III, and then graphene / aramid III composite fibers were prepared by spinning, wherein the graphene content was 0.05 wt%, the breaking strength was 24.78 cN / dTex, the tensile modulus was 776.63 cN / dTex, and the elongation at break was 3.68%.

[0076] Comparative Example 6

[0077] 2 g of porous redox graphene powder with a size of 500 nm, 3 layers, a chlorine content of 3.52 atom%, and a pore density of 1.02 m 3 g -1 was dispersed in DMAc to obtain a graphene dispersion liquid with a concentration of 20 mg mL -1 . The graphene dispersion liquid was added in situ during the polymerization of aramid III, and then graphene / aramid III composite fibers were prepared by spinning, wherein the graphene content was 2 wt%, the breaking strength was 29.84 cN / dTex, the tensile modulus was 796.28 cN / dTex, and the elongation at break was 3.81%.

[0078] The parameters and test results of Examples 1-9 and Comparative Examples 1-6 are shown in Table 1.

[0079] Table 1

[0080]

[0081]

[0082] It is shown from the above table that the strength of the composite fiber is related to the size, Cl content, and pore density of the acyl chloride porous graphene; within a certain range of graphene size, the smaller the size, the higher the mechanical properties of the composite fiber; the higher the chlorine content, the higher the mechanical properties of the composite fiber; the greater the pore density, the higher the mechanical properties of the composite fiber; and the fewer the layers, the higher the mechanical properties of the composite fiber.

[0083] The preferred embodiments of the application disclosed above are only to facilitate the elucidation of the application. The preferred embodiments do not describe all the details of the application and limit the application to the specific embodiments described. Obviously, many modifications and variations can be made in light of the teachings above. The description is chosen and described in order to best explain the principles of the application and its practical application to thereby enable others skilled in the art to best utilize the application and get the best results from the application. The application is only limited by the claims and their full scope and equivalents.

Claims

1. A modified aramid III composite fiber, characterized by, The composite fiber comprises porous graphene and aramid III polymer, and the aramid III polymer and the acyl chloride graphene are connected in the form of chemical covalent bond. The porous graphene has a particle size of 500 nm-2 mu m, and a layer number of 3-5 layers; the porous graphene has a pore density of 0.6-1.26 m 3 g -1 / g, the content of the porous graphene is 0.01wt%-0.5wt%, and the chlorine content of the porous graphene is 0.5-3.52 atom%. The preparation method of the modified aramid III composite fiber comprises: S1, dispersing the porous graphene with acyl chloride bond on the surface in N,N dimethylacetamide to form a first dispersion liquid uniformly dispersed; And S2, adding the first dispersion liquid in the polymerization process of forming the aramid III polymer to carry out polymerization reaction to form a polymerization liquid.

2. The modified aramid III composite fiber according to claim 1, characterized by, The covalent bond is an amide bond.

3. The modified aramid III composite fiber according to claim 1, characterized by, The breaking strength of the graphene modified aramid III composite fiber is 33-35 cN / dtex, the elastic modulus is 800-900 cN / dtex, and the breaking elongation is 3.9-4.1%.

4. A method for producing the modified aramid III composite fiber according to any one of claims 1 to 3, characterized by, Comprise: S1, dispersing the porous graphene with acyl chloride bond on the surface in N,N dimethylacetamide to form a first dispersion liquid uniformly dispersed; And S2, adding the first dispersion liquid in the polymerization process of forming the aramid III polymer to carry out polymerization reaction to form a polymerization liquid.

5. The method of producing a modified aramid III composite fiber according to claim 4, characterized by, Also comprise: S3, wet spinning the polymerization liquid.

6. The method of producing a modified aramid III composite fiber according to claim 4, characterized by, The concentration of the porous graphene in the first dispersion is 0.01-50 mg mL -1 .

Images