Composite material as well as preparation method and application thereof

Abstract

The invention relates to the technical field of flame-retardant composite materials, in particular to a composite material and a preparation method and application thereof. The composite material comprises fibers, resin and a flame retardant, the flame retardant comprises silicon dioxide aerogel and phytic acid derivatives, and on the basis of the total weight of the composite material, the content of the fibers in the composite material is 20-80 wt%, the content of the resin in the composite material is 18.5-79 wt%, and the content of the flame retardant in the composite material is 0.1-2 wt%. The limit oxygen index of the composite material is 28-36%, the measurement grade of UL-94 is V-0 to V-2, and the interlaminar shear strength is 87-89 MPa. The composite material disclosed by the invention is applied to actual production, life and research, and not only has relatively high flame retardant property, but also has relatively good mechanical property.

Description

Technical Field

[0001] The present invention relates to the technical field of flame - retardant composite materials, and particularly to a composite material, a preparation method thereof and an application thereof. Background Art

[0002] In the past decade, the losses caused by fires have far exceeded those of natural disasters. Moreover, the environmental pollution problems caused by fires have become increasingly serious. Fire statistics show that when a fire occurs, the initially ignited items are almost all polymer materials such as rubber, plastic, and fabric. Such results prove that polymer materials are flammable and pose fire risks and hazards. Flame - retardant additives are an effective way to mitigate such hazards and reduce fire risks. Therefore, for many years, in daily production, life and scientific research, people have increasingly favored the use of polymer fire - proof materials containing flame retardants.

[0003] However, the use of conventional flame retardants is difficult to endow polymers with high flame - retardant properties, and it will also reduce the mechanical properties of polymer materials. When burning, a large amount of thick smoke and toxic gases will be released, seriously affecting the application of polymer materials in actual production, life and research. Therefore, there is an urgent need for an environmentally friendly flame retardant to suit various flame - retardant applications. Summary of the Invention

[0004] The object of the present invention is to overcome the problems of low flame - retardant properties and poor mechanical properties of flame - retardant modified polymer materials existing in the prior art, and to provide a composite material, a preparation method thereof and an application thereof. The composite material has good mechanical properties while having high flame - retardant properties.

[0005] To achieve the above object, in the first aspect of the present invention, a composite material is provided. The composite material comprises fibers, a resin and a flame retardant, wherein the flame retardant comprises silica aerogel and phytic acid derivatives.

[0006] In the second aspect of the present invention, a method for preparing a composite material is provided. The method comprises the following steps:

[0007] (1) Perform a first mixing of silica aerogel and phytic acid derivatives to obtain a flame retardant;

[0008] (2) Perform a second mixing of the flame retardant obtained in step (1) with the resin to obtain a flame - retardant resin;

[0009] (3) Perform a third mixing of the flame - retardant resin obtained in step (2) with the fibers to obtain the composite material.

[0010] In the third aspect of the present invention, a composite material obtained by the method described in the second aspect of the present invention is provided.

[0011] The fourth aspect of the present invention provides an application of the composite material described in the first aspect or the composite material described in the third aspect in flame retardancy.

[0012] Through the above technical solutions, the present invention uses resin as the matrix, and uses a composite silica aerogel containing silica aerogel and phytic acid derivatives as the flame retardant, and mixes it with fibers to obtain a composite material with significantly improved flame retardancy. Silica aerogel is a highly dispersed solid material with a nano-porous network structure formed by the aggregation of nano-scale particles and filled with gaseous dispersion media in the voids. It has characteristics such as nano-porous structure, low density, low dielectric constant, low thermal conductivity, high porosity, and high specific surface area. It can not only disperse the phytic acid derivative-based phosphorus flame retardant more uniformly, but also the extremely low thermal conductivity and pore size of silica aerogel itself have a binding effect on air molecules, complementing the dense and continuous carbon layer obtained by the decomposition of phytic acid during the combustion process, effectively playing a good adiabatic flame retardant protection role and improving the utilization rate of the phytic acid derivative-based phosphorus flame retardant. Performance tests were carried out on the composite material prepared by the present invention. It can be seen from the test results (see Table 1) that compared with the comparative example, the composite material of the present invention has a higher limiting oxygen index, a lower UL-94 rating and smoke release amount, and can also have good mechanical properties. In addition, compared with the existing flame retardant materials, the composite material provided by the present invention directly uses the composite aerogel flame retardant to replace the filler in the mature formula, which is easy to operate, not only improves the flame retardant performance of the carbon fiber composite material, but also has the advantages of biocompatibility, environmental friendliness, easy availability, renewable, and non-toxicity. Detailed Embodiments

[0013] In the ranges disclosed herein, the endpoints and any values are not limited to the exact ranges or values, and these ranges or values should be understood to include values close to these ranges or values. For numerical ranges, the endpoint values of each range, between the endpoint values of each range and a single point value, and between single point values can be combined with each other to obtain one or more new numerical ranges, and these numerical ranges should be regarded as specifically disclosed herein.

[0014] The following will detail the specific embodiments of the present invention. It should be understood that the specific embodiments described herein are only for the purpose of illustrating and explaining the present invention, and are not used to limit the present invention.

[0015] The first aspect of the present invention provides a composite material, the composite material comprising fibers, resin and a flame retardant, wherein the flame retardant comprises silica aerogel and phytic acid derivatives.

[0016] In the present invention, silica aerogel and phytic acid derivatives are compounded and added as a flame retardant to a resin matrix. By utilizing the performance characteristics of silica aerogel: nano-porous structure, low density, low dielectric constant, low thermal conductivity, high porosity, high specific surface area, etc., not only can the phytic acid derivative-based phosphorus flame retardant be more uniformly dispersed in the resin, giving full play to the flame retardant effect of the phytic acid derivative-based phosphorus flame retardant, but also the extremely low thermal conductivity of silica aerogel itself and the pore size have a binding effect on air molecules, effectively playing a good adiabatic and flame retardant protection role and improving the utilization rate of the phytic acid derivative-based phosphorus flame retardant. In addition, the composite material of the present invention still has good mechanical properties when the flame retardancy is improved.

[0017] According to the present invention, based on the total weight of the composite material, preferably, the content of fibers in the composite material is 20 - 80% by weight, the content of resin is 18.5 - 79% by weight, and the content of flame retardant is 0.1 - 2% by weight; more preferably, the content of fibers in the composite material is 30 - 64% by weight, the content of resin is 35 - 69% by weight, and the content of flame retardant is 0.35 - 1.8% by weight.

[0018] According to the present invention, in order to achieve the improvement of the flame retardancy of the resin composite material and the reduction of the smoke release amount during the combustion of the composite material, while maintaining the good mechanical properties of the composite material, based on the total weight of the flame retardant, preferably, the content of silica aerogel in the flame retardant is 50 - 98% by weight, and the content of phytic acid derivatives is 2 - 50% by weight; more preferably, the content of silica aerogel in the flame retardant is 58 - 65% by weight, and the content of phytic acid derivatives is 35 - 42% by weight.

[0019] According to the present invention, in order to meet various flame retardant applications of the composite material, preferably, the fiber is selected from at least one of carbon fiber, glass fiber, and aramid fiber; more preferably, the fiber is carbon fiber. The present invention has no special requirements for the form of existence of the carbon fiber. Preferably, the form of existence of the carbon fiber can be a carbon fiber fabric. The present invention has no specific limitation on the areal density of the carbon fiber fabric. For example, it can be 50 gsm - 1000 gsm.

[0020] Preferably, the resin is selected from at least one of epoxy resin, vinyl resin, polyurethane resin, and phenolic resin, and more preferably epoxy resin.

[0021] Preferably, the viscosity of the epoxy resin < 500 mPa·s.

[0022] In the present invention, in order to make the composite aerogel flame retardant disperse uniformly in the resin matrix and effectively improve the flame retardancy of the composite material, preferably, the particle size of the silica aerogel is 1000 - 2000 mesh; more preferably 1300 - 1500 mesh.

[0023] In the present invention, the phytic acid derivatives can be obtained by commercial purchase or prepared by any existing method.

[0024] In the present invention, preferably, the phytic acid derivatives are prepared by the reaction of phytic acid and urea. The specific steps include: mixing phytic acid, urea and water, stirring and stirring at 60 - 80 °C for 1 - 3 h to obtain a phytic acid derivative solution.

[0025] According to the present invention, in order to better improve the flame retardancy of the composite material, preferably, the mass ratio of urea to phytic acid is 0.6 - 3:1, more preferably 0.6 - 2.2:1.

[0026] Other raw materials used in the present invention can be obtained by commercial purchase or prepared by any existing method.

[0027] In the present invention, according to the ASTM D2863 - 2009 standard, the limiting oxygen index (LOI) of the resin composite material is tested using a limiting oxygen index tester. Specifically: placing the resin composite material sample in the combustion chamber and adjusting the oxygen content in the atmosphere to find the lowest oxygen concentration that can maintain combustion.

[0028] According to the ASTM D3801 standard, a vertical burning (UL - 94) test is performed on the composite material sample.

[0029] According to the ASTM E1354 / ISO 5660 - 1 standard, a cone calorimeter test (CCT) is performed on the composite material sample.

[0030] According to the ASTM D 2344 standard, an interlaminar shear strength test is performed on the composite material sample.

[0031] According to the present invention, preferably, the limiting oxygen index of the composite material is 28 - 36%, the determination grade of UL - 94 is V - 0 to V - 2, and the interlaminar shear strength is 85 - 89 MPa.

[0032] In the present invention, the composition of the composite material can be calculated from the feeding amount.

[0033] The present invention does not particularly limit the preparation method of the composite resin, as long as the composite resin with the above composition can be obtained. According to a preferred embodiment of the present invention, the second aspect of the present invention provides a method for preparing a composite material, wherein the method includes the following steps:

[0034] (1) Mix silica aerogel and phytic acid derivatives for the first time to obtain a flame retardant;

[0035] (2) Mix the flame retardant obtained in step (1) with a resin for the second time to obtain a flame retardant resin;

[0036] (3) Mix the flame retardant resin obtained in step (2) with fibers for the third time to obtain the composite material.

[0037] In the preparation method of the present invention, all raw materials used can be commercially available products or prepared by any existing method.

[0038] According to the preparation method of the present invention, in order to make the phytic acid derivative-based phosphorus-based flame retardant more uniformly dispersed in the resin matrix through compounding with silica aerogel, preferably, in step (1), the first mixing method is impregnation; specifically, the silica aerogel can be impregnated with an equal volume or an excessive volume of an aqueous solution containing phytic acid derivatives.

[0039] According to the preparation method of the present invention, in order to improve the flame retardancy of the prepared resin composite material and reduce the smoke release amount during the combustion of the composite material, and maintain the good mechanical properties of the composite material, preferably, in step (1), the weight ratio of the silica aerogel to the phytic acid derivatives is 1:0.02 - 1, and further preferably 1:0.5 - 0.8.

[0040] According to the preparation method of the present invention, in order to make the phytic acid derivatives better compounded on the silica aerogel, preferably, the temperature of the impregnation is 20 - 30 °C.

[0041] According to the preparation method of the present invention, after the impregnation, a drying step is further included; preferably, the drying temperature is 40 - 120 °C and the time is 1 - 24 h.

[0042] According to the method provided by the present invention, the types, sources, and selection ranges of the molecular weights of cellulose, resin, phytic acid, and phytic acid derivatives can be the same as those described in the first aspect of the present invention, and will not be elaborated herein.

[0043] According to the preparation method of the present invention, in order to make the composite aerogel flame retardant more uniformly mixed with the resin matrix and increase the compatibility between different materials, preferably, in step (2), the second mixing method is stirring, and the conditions include: the stirring speed is 300 - 500 rpm, the temperature is 20 - 30 °C, and the time is 20 - 30 min.

[0044] According to the preparation method of the present invention, in order to improve the flame retardancy of the obtained resin composite material and reduce the smoke release amount during the combustion of the composite material, and maintain good mechanical properties of the composite material, preferably, in step (2), the mass ratio of the flame retardant to the resin is 0.01 - 0.05:1, preferably 0.03 - 0.05.

[0045] Preferably, in step (3), the third mixing method is vacuum infusion; more preferably, it is vacuum infusion. Specifically, the cut carbon fiber cloth is laid in the vacuum infusion mold as required, then a release cloth is laid on the carbon cloth, and then a flow guiding net is laid on the release cloth. Finally, a vacuum bag film is adhered with a sealing tape, and a resin vacuum tube inlet and outlet are installed when adhering the vacuum film. After the mold is prepared, connect the gas source, turn on the vacuum pump, and check the vacuum degree. If the vacuum is maintained well, turn on the vacuum pump again, and suck the flame retardant resin prepared in step (2) into the mold through vacuum until the resin completely impregnates the carbon fiber cloth. After sealing the vacuum tubes at the inlet and outlet, turn off the vacuum pump and maintain the vacuum until the sample is cured.

[0046] Preferably, the mass ratio of the flame retardant resin to the fiber is 0.25 - 4:1, more preferably 0.43 - 2.33:1.

[0047] The third aspect of the present invention provides a composite material prepared by the method described in the second aspect of the present invention.

[0048] The fourth aspect of the present invention provides an application of the composite material described in the first aspect or the composite material described in the third aspect in flame retardancy.

[0049] The present invention will be described in detail below through examples.

[0050] Silica aerogel, purchased from Zhongrun Kezi.

[0051] Epoxy resin, viscosity 200 - 300 mPa·s, purchased from Huachang Polymer Co., Ltd., East China University of Science and Technology, with the brand number 3312.

[0052] Carbon fiber cloth, with a surface density of 200 gsm.

[0053] Example 1

[0054] (1) Prepare a solution by mixing 10 g of phytic acid, 6 g of urea, and 32 g of water. Stir the solution at 70 °C for 2 h. Add the resulting solution to 112 g of water and stir well to obtain an impregnating solution containing phytic acid derivatives. Impregnate silica aerogel with the impregnating solution in an equal-volume manner. Dry the impregnated aerogel at 40 °C for 4 h to obtain a flame retardant containing silica aerogel and phytic acid derivatives. Crush the flame retardant through a 1000-mesh sieve. Among them, in the flame retardant, the content of silica aerogel is 65 wt%, and the content of phytic acid derivatives is 35 wt%.

[0055] (2) Mix 10 g of the flame retardant prepared in step (1) with 190 g of epoxy resin. Stir at a temperature of 20 °C and a speed of 300 rpm for 20 min to obtain a flame-retardant resin.

[0056] (3) Perform vacuum infusion on 200 g of the flame-retardant resin prepared in step (2) and 360 g of carbon fiber cloth to obtain a board 1 containing composite aerogel. The specific steps are as follows: Lay the cut carbon fiber cloth (size: 300 mm * 300 mm) (laying thickness 4 mm) in a vacuum infusion mold. Then lay a release cloth on the carbon cloth, and then lay a flow guiding net on the release cloth. Finally, use a sealing tape to stick the vacuum bag film. While sticking the vacuum film, install the resin vacuum tube inlet and outlet for guiding. After the mold is prepared, connect the air source, turn on the vacuum pump, and check the vacuum degree. If the vacuum is maintained well, suck the flame-retardant resin prepared in step (2) into the mold through vacuum until the resin completely impregnates the carbon fiber cloth. Then seal the vacuum tubes at the inlet and outlet for guiding, turn off the vacuum pump, and maintain the vacuum state until the sample is cured.

[0057] Test the performance parameters of board 1, and the test results are shown in Table 1.

[0058] Example 2

[0059] (1) Prepare a solution by mixing 10 g of phytic acid, 11 g of urea, and 42 g of water. Stir the solution at 70 °C for 2 h. Add the resulting solution to 147 g of water and stir well to obtain an impregnating solution containing phytic acid derivatives. Impregnate silica aerogel with the impregnating solution in an equal-volume manner. Dry the impregnated aerogel at 60 °C for 8 h to obtain a flame retardant containing silica aerogel and phytic acid derivatives. Among them, in the flame retardant, the content of silica aerogel is 58 wt%, and the content of phytic acid derivatives is 42 wt%.

[0060] (2) Mix 10 g of the flame retardant prepared in step (1) with 190 g of epoxy resin. Stir at a temperature of 22 °C and a speed of 350 rpm for 25 min to obtain a flame-retardant resin.

[0061] (3) Vacuum infusion is carried out on 200 g of the flame-retardant resin prepared in step (2) and 360 g of carbon fiber cloth to obtain a plate 2 containing composite aerogel. The specific steps are as follows: Lay the cut carbon fiber cloth (size: 300 mm * 300 mm) (laying thickness: 4 mm) in a vacuum infusion mold, then lay a release cloth on the carbon cloth, then lay a flow guide net on the release cloth, and finally use a sealing tape to stick the vacuum bag film. While sticking the vacuum film, install the resin vacuum tube inlet and outlet for guiding. After the mold is prepared, connect the gas source, turn on the vacuum pump, check the vacuum degree. If the vacuum is maintained well, suck the flame-retardant resin prepared in step (2) into the mold by vacuum until the resin completely impregnates the carbon fiber cloth, then seal the vacuum tubes at the inlet and outlet for guiding, turn off the vacuum pump, and maintain the vacuum state until the sample is cured.

[0062] Test the performance parameters of plate 2, and the test results are shown in Table 1.

[0063] Example 3

[0064] (1) Prepare a solution by mixing 5 g of phytic acid, 11 g of urea and 32 g of water, stir it at 70 °C for 2 h, add the obtained solution to 112 g of water, and stir evenly to obtain an impregnating solution containing phytic acid derivatives. Perform equal-volume impregnation on silica aerogel with the impregnating solution, and dry the impregnated aerogel at 80 °C for 12 h to obtain a flame retardant containing silica aerogel and phytic acid derivatives. Among them, the content of silica aerogel in the flame retardant is 83% by weight, and the content of phytic acid derivatives is 17% by weight.

[0065] (2) Mix 10 g of the flame retardant prepared in step (1) with 190 g of epoxy resin, and stir at a temperature of 25 °C and a speed of 380 rpm for 30 min to obtain a flame-retardant resin.

[0066] (3) Vacuum infusion is carried out on 200 g of the flame-retardant resin prepared in step (2) and 360 g of carbon fiber cloth to obtain a plate 3 containing composite aerogel. The specific steps are as follows: Lay the cut carbon fiber cloth (size: 300 mm * 300 mm) (laying thickness: 4 mm) in a vacuum infusion mold, then lay a release cloth on the carbon cloth, then lay a flow guide net on the release cloth, and finally use a sealing tape to stick the vacuum bag film. While sticking the vacuum film, install the resin vacuum tube inlet and outlet for guiding. After the mold is prepared, connect the gas source, turn on the vacuum pump, check the vacuum degree. If the vacuum is maintained well, suck the flame-retardant resin prepared in step (2) into the mold by vacuum until the resin completely impregnates the carbon fiber cloth, then seal the vacuum tubes at the inlet and outlet for guiding, turn off the vacuum pump, and maintain the vacuum state until the sample is cured.

[0067] The performance parameters of the sheet 3 were tested, and the test results are shown in Table 1.

[0068] Example 4

[0069] (1) 10 g of phytic acid, 11 g of urea and 42 g of water were formulated into a solution, stirred at 70 °C for 2 h, the obtained solution was added to 357 g of water, and stirred evenly to obtain an impregnating solution containing phytic acid derivatives; the silica aerogel was impregnated with the impregnating solution in an equal volume, and the impregnated aerogel was dried at 100 °C for 16 h to obtain a flame retardant containing silica aerogel and phytic acid derivatives. Among them, in the flame retardant, the content of silica aerogel is 86% by weight, and the content of phytic acid derivatives is 14% by weight;

[0070] (2) 4 g of the flame retardant prepared in step (1) was mixed with 196 g of epoxy resin, and stirred at a temperature of 27 °C and a speed of 400 rpm for 28 min to obtain a flame retardant resin;

[0071] (3) 200 g of the flame retardant resin prepared in step (2) was vacuum infused with 360 g of carbon fiber cloth to obtain a sheet 4 containing composite aerogel. The specific steps are as follows: The cut carbon fiber cloth (size 300 mm * 300 mm) was laid (laying thickness 4 mm) in a vacuum infusion mold, then a release cloth was laid on the carbon cloth, and a flow guide net was laid on the release cloth. Finally, the vacuum bag film was adhered with a sealing tape. While adhering the vacuum film, the resin vacuum tube inlet and outlet were installed; after the mold was prepared, the air source was connected, the vacuum pump was turned on, and the vacuum degree was inspected. If the vacuum was maintained well, the flame retardant resin prepared in step (2) was sucked into the mold by vacuum until the resin completely impregnated the carbon fiber cloth, and then the vacuum tubes at the inlet and outlet of the flow guide were sealed, the vacuum pump was turned off, and the vacuum state was maintained until the sample was cured.

[0072] The performance parameters of the sheet 4 were tested, and the test results are shown in Table 1.

[0073] Example 5

[0074] (1) 10 g of phytic acid, 11 g of urea and 42 g of water were formulated into a solution, stirred at 70 °C for 2 h, the obtained solution was added to 2134 g of water, and stirred evenly to obtain an impregnating solution containing phytic acid derivatives; the silica aerogel was impregnated with the impregnating solution in an equal volume, and the impregnated aerogel was dried at 120 °C for 20 h to obtain a flame retardant containing silica aerogel and phytic acid derivatives. Among them, in the flame retardant, the content of silica aerogel is 96% by weight, and the content of phytic acid derivatives is 4% by weight;

[0075] (2) Mix 2 g of the flame retardant prepared in step (1) with 198 g of epoxy resin, and stir for 26 min at a temperature of 30 °C and a speed of 360 rpm to obtain flame-retardant resin;

[0076] (3) Vacuum-infuse 200 g of the flame-retardant resin prepared in step (2) with 360 g of carbon fiber cloth to obtain Sheet 5 containing composite aerogel. The specific steps are as follows: Lay the cut carbon fiber cloth (size: 300 mm * 300 mm) (laying thickness 4 mm) in the vacuum infusion mold, then lay a release cloth on the carbon cloth, then lay a flow guide net on the release cloth, and finally use a sealing tape to stick the vacuum bag film. While sticking the vacuum film, install the resin vacuum tube inlet and outlet for guiding; After the mold preparation is completed, connect the air source, turn on the vacuum pump, check the vacuum degree. If the vacuum is maintained well, suck the flame-retardant resin prepared in step (2) into the mold through vacuum until the resin completely impregnates the carbon fiber cloth, then seal the vacuum tubes at the inlet and outlet for guiding, turn off the vacuum pump, and maintain the vacuum state until the sample cures.

[0077] Test the performance parameters of Sheet 5, and the test results are shown in Table 1.

[0078] Comparative Example 1

[0079] According to the method of step (3) of Example 1, except that in the vacuum infusion process, a pure resin matrix is added to obtain Sheet 6.

[0080] Test the performance parameters of Sheet 6, and the test results are shown in Table 1.

[0081] Comparative Example 2

[0082] According to the methods of steps (2) and (3) of Example 1, except that the flame retardant is pure silica aerogel to obtain Sheet 7.

[0083] Test the performance parameters of Sheet 7, and the test results are shown in Table 1.

[0084] Table 1

[0085]

[0086] As can be seen from Table 1, compared with Comparative Example 1, the mechanical properties of the sheets prepared in Examples 1 - 5 change less, indicating that the addition of the composite aerogel flame retardant has little effect on the mechanical properties of the sheets while improving the flame retardant performance of the sheets.

[0087] Compared with Examples 1 and 3, the flame retardant performance of the sheet prepared in Example 2 is the best, indicating that a suitable ratio between phytic acid and urea can significantly improve the flame retardant performance of the resin.

[0088] Compared with Examples 4 and 5, the flame retardant performance of the board prepared in Example 2 is the best, indicating that the higher the content of phytic acid derivatives in the composite aerogel, the better the flame retardant performance of the resin board prepared.

[0089] Compared with Comparative Example 2, the flame retardant performance of the boards prepared in Examples 1, 2, 3, 4 and 5 has been improved, and the interlaminar shear strength of the boards has also been improved. This shows that the combination of phytic acid derivatives and silica aerogel can not only improve the flame retardant performance of the resin, but also improve the mechanical properties of the resin. During the combustion process of the composite material of the present invention, the phytic acid derivatives in the composite aerogel flame retardant can be decomposed into phosphoric acid or metaphosphoric acid, catalyzing the formation of a phosphorus-containing carbon layer. At the same time, the silica aerogel can further prevent the transfer of heat, protecting the resin matrix and showing excellent continuous combustion and smoke suppression performance, thereby improving the flame retardant performance of the composite material.

[0090] It can be seen from the above examples and comparative examples that in the present invention, phytic acid derivatives are combined with silica aerogel, and the obtained composite aerogel is added as a flame retardant to the resin matrix. From the data in Table 1, compared with the resin composite material prepared by using pure silica aerogel as a flame retardant, not only can the flame retardant performance of the composite material be significantly improved, but the addition of phytic acid derivatives can also improve the mechanical properties of the resin.

[0091] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited thereto. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solutions of the present invention, including any other suitable combination of each technical feature. These simple modifications and combinations should also be regarded as the content disclosed by the present invention and fall within the protection scope of the present invention.

Claims

1. A composite material, characterized in that, The composite material comprises fibers, resin and a flame retardant, wherein the flame retardant comprises silica aerogel and phytic acid derivatives.

2. The composite material according to claim 1, wherein, Based on the total weight of the composite material, the content of the fibers in the composite material is 20-80% by weight, the content of the resin is 18.5-79% by weight, and the content of the flame retardant is 0.1-2% by weight.

3. The composite material according to claim 1 or 2, wherein, Based on the total weight of the composite material, the content of the fibers in the composite material is 30-64% by weight, the content of the resin is 35-69% by weight, and the content of the flame retardant is 0.35-1.8% by weight.

4. The composite material according to any one of claims 1-3, wherein, Based on the total weight of the flame retardant, the content of silica aerogel in the flame retardant is 50-98% by weight, and the content of phytic acid derivatives is 2-50% by weight; Preferably, the content of silica aerogel in the flame retardant is 58-65% by weight, and the content of phytic acid derivatives is 35-42% by weight.

5. The composite material according to any one of claims 1-4, wherein, The fibers are selected from at least one of carbon fibers, glass fibers and aramid fibers; Preferably, the fibers are carbon fibers, the carbon fibers are carbon fiber fabrics, and the areal density of the carbon fiber fabrics is 50 gsm - 1000 gsm; And / or, the resin is selected from at least one of epoxy resin, vinyl resin, polyurethane resin and phenolic resin, preferably epoxy resin; And / or, the particle size of the silica aerogel is 1000 - 2000 mesh; And / or, the phytic acid derivatives are prepared by the reaction of phytic acid and urea; Preferably, the conditions of the reaction include: the mass ratio of urea to phytic acid is 0.6 - 3:1, the reaction temperature is 60 - 80 °C, and the time is 1 - 3 h; More preferably, the mass ratio of urea to phytic acid is 0.6 - 2.2:

1.

6. The composite material according to any one of claims 1-5, wherein, The limiting oxygen index of the composite material is 28 - 36%, the UL-94 determination grade is V-0 to V-2, and the interlaminar shear strength is 87 - 89 MPa.

7. A method for preparing a composite material, characterized in that, The method comprises the following steps: (1) Carry out the first mixing of silica aerogel and phytic acid derivatives to obtain a flame retardant; (2) Carry out the second mixing of the flame retardant obtained in step (1) and the resin to obtain a flame retardant resin; (3) Carry out the third mixing of the flame retardant resin obtained in step (2) and the fibers to obtain the composite material.

8. The method according to claim 7, wherein In step (1), the first mixing method is impregnation; Preferably, the impregnation is equal-volume impregnation or excess impregnation; And / or, the weight ratio of silica aerogel to phytic acid derivatives is 1:0.02 - 1, preferably 1:0.5 - 0.8; And / or, the particle size of the silica aerogel is 1000 - 2000 mesh; And / or, the phytic acid derivatives are prepared by the reaction of phytic acid and urea; Preferably, the conditions of the reaction include: the mass ratio of urea to phytic acid is 0.6 - 3:1, the reaction temperature is 60 - 80 °C, and the time is 1 - 3 h; More preferably, the mass ratio of urea to phytic acid is 0.6 - 2.2:

1.

9. The method according to claim 8, wherein, The temperature of the impregnation is 20 - 30 °C; Preferably, a drying step is further included after the impregnation; Further preferably, the drying temperature is 40 - 120 °C and the time is 1 - 24 h.

10. The method according to any one of claims 7-9, wherein, In step (2), the second mixing is performed by stirring, and the conditions include: the stirring speed is 300 - 500 rpm, the temperature is 20 - 30 °C, and the time is 20 - 30 min; and / or, the mass ratio of the flame retardant to the resin is 0.01 - 0.05:1, preferably 0.03 - 0.05; and / or, the resin is selected from at least one of epoxy resin, vinyl resin, polyurethane resin, and phenolic resin, preferably epoxy resin.

11. The method according to any one of claims 7-10, wherein In step (3), the third mixing is performed by a vacuum infusion process; and / or, the mass ratio of the flame retardant resin to the fiber is 0.25 - 4:1, preferably 0.43 - 2.33:1; and / or, the fiber is selected from at least one of carbon fiber, glass fiber, and aramid fiber; Preferably, the fiber is carbon fiber, the carbon fiber is a carbon fiber fabric, and the areal density of the carbon fiber fabric is 50 gsm - 1000 gsm.

12. A composite material prepared by the method according to any one of claims 7 - 11.

13. Use of the composite material according to any one of claims 1 - 6 and 12 in flame retardancy.

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