Modified basalt fiber fabric, composite material thereof, and method for preparing the same

Abstract

The present application relates to the technical field of composite materials, in particular to modified basalt fiber fabric, composite material thereof and preparation method thereof. The preparation method of the modified basalt fiber fabric comprises the following steps: mixing and weaving basalt fibers and thermoplastic fibers to form a mixed woven fabric; then, activating the mixed woven fabric to form silicon hydroxyl on the surface of the mixed woven fabric; then, chemically grafting to link silicon-oxygen-silicon chains to the mixed woven fabric; and then, loading nanoparticles on the mixed woven fabric containing the silicon-oxygen-silicon chains. The method can improve the low interface strength of the basalt fiber fabric, thereby significantly improving the mechanical properties of the basalt fiber fabric and expanding the application range of the basalt fiber fabric.

Description

Technical Field

[0001] This invention relates to the field of composite materials technology, and more specifically, to modified basalt fiber fabrics, their composite materials, and methods for their preparation. Background Technology

[0002] Fiber-reinforced resin matrix composites possess advantages such as light weight, high toughness, easy reprocessing and production, low cost, and high specific strength, exhibiting strong adaptability to loads and environmental conditions. Due to the anisotropy and heterogeneity of composite materials, ensuring high reliability and reproducibility in industrial production is crucial.

[0003] The disadvantages of thermosetting resins include long curing times and the inability to reuse the finished products. In contrast, thermoplastic resins can be repeatedly heated to soften and cooled to cure, with no intermolecular cross-linking. During molding, thermoplastic resins soften and flow upon pressure and heating, without chemical cross-linking, allowing them to be shaped within a mold and cooled to set, resulting in the desired product shape. Furthermore, thermoplastic composites are recyclable and reprocessable. Due to these characteristics, fiber-reinforced thermoplastic resin-based composites have become a key research focus.

[0004] However, the high viscosity of thermoplastic resins makes it difficult to impregnate them into tightly interwoven fiber bundles to fill the voids in the structure, especially when preparing composites with a high fiber volume fraction. This results in a significant gap between the theoretical and actual mechanical properties of fiber-reinforced thermoplastic resin matrix composites, limiting their practical applications. High-performance thermoplastic composites can be categorized by fiber size into short-fiber composites, long-fiber composites, and continuous fiber fabric composites. Composites made from continuous fiber fabrics can maximize the high strength and high modulus of the reinforcement. Meanwhile, to improve their mechanical properties and broaden their applications, the scientific community and industrial manufacturers are researching increasingly sophisticated strategies and methods to enhance the interfacial interaction between continuous fiber fabrics and the resin matrix.

[0005] The interfacial effect of composite materials is determined not only by the morphology, structure, and properties of the resin matrix and reinforcing fibers, but also by the interfacial stress generated during interface formation and the interactions and chemical reactions between the components during the composite material's preparation. With the deepening of interface research, interface theory is constantly being discussed and refined. Currently, the generally accepted interface theories mainly include chemical bonding theory, mechanical interlocking theory, and wettability theory. The properties of composite materials are jointly determined by the fibers, resin, and their interface. The interfacial phase between the fiber and the resin matrix is ​​not simply the geometric surface of their contact, but rather a transitional region with a certain thickness and structure, jointly composed of the resin matrix and fibers. Its structure and properties directly affect the structure and properties of the composite material.

[0006] Basalt fibers have a smooth surface, while thermoplastic resins are chemically inert and mostly have non-polar bonds. This makes it difficult for basalt fibers to form mechanical and chemical bonds with thermoplastic resins. As a result, the mechanical properties of the interface of clean basalt fiber composites are poor, which greatly limits their further application.

[0007] In view of this, the present invention is proposed. Summary of the Invention

[0008] The purpose of this invention is to provide modified basalt fiber fabrics, their composite materials, and methods for their preparation. The method for modifying basalt fiber fabrics provided in this invention can improve the problem of low interfacial strength, thereby significantly enhancing its mechanical properties and expanding its application range.

[0009] This invention is implemented as follows:

[0010] In a first aspect, the present invention provides a method for preparing modified basalt fiber fabric, comprising: mixing and weaving basalt fiber and thermoplastic fiber to form a mixed woven fabric;

[0011] Then, the blended fabric is activated to form silanol groups on the surface of the blended fabric.

[0012] Next, chemical grafting is performed to link silicon-oxygen chains to the woven fabric;

[0013] Then, nanoparticles are loaded onto the woven fabric containing the silicon-oxygen chains.

[0014] In an optional embodiment, the basalt fiber is in the weft direction during the mixed weaving process, and the thermoplastic fiber or both the thermoplastic fiber and the basalt fiber are in the radial direction.

[0015] Preferably, the mass ratio of the basalt fiber to the thermoplastic fiber is (7:3)-(6:4);

[0016] Preferably, the weight of the blended fabric is 200-300 g / m². 2 .

[0017] In an optional embodiment, the activation treatment step includes: mixing the blended fabric, organic solvent and water, followed by ultrasonication, and then drying;

[0018] Preferably, the organic solvent is selected from alcohol solvents and / or ketone solvents, preferably monohydric alcohols, more preferably C1-C5 monohydric alcohols, and most preferably any one or at least a combination of two of methanol, ethanol and acetone.

[0019] Preferably, the mass of the blended fabric accounts for 40-90% of the total mass of the blended fabric, the organic solvent, and the water;

[0020] Preferably, the mass ratio of the organic solvent to the water is (3:8)-(3:13);

[0021] Preferably, the drying conditions include a temperature of 40-90°C and a time of 2-10 hours.

[0022] In an optional embodiment, the side groups of the silicon oxide chain are amino groups;

[0023] Preferably, the chemical grafting step includes: mixing the activated hybrid fabric with a modifier and reacting them;

[0024] Preferably, the modifier is selected from siloxane compounds, and is preferably any one or at least a combination of two of γ-ureidopropyltriethoxysilane, β-aminoethyl-γ-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, phenylaminomethyltrimethoxysilane and phenylaminomethyltriethoxysilane.

[0025] Preferably, the mass ratio of the activated blended fabric to the modifier is (4:1.5)-(12:1.5);

[0026] Preferably, the reaction conditions include a temperature of 90-130°C and a time of 4-6 hours.

[0027] In an optional embodiment, the step of loading the nanoparticles includes: mixing the woven fabric containing the silicon oxide chains, the nanoparticles, and a mixed solvent, and then sonicating them;

[0028] Preferably, the mixed solvent comprises water and an organic solvent, wherein the volume ratio of the water to the organic solvent is (1:1) to (2:5);

[0029] Preferably, the organic solvent is selected from alcohol solvents and / or ketone solvents, preferably monohydric alcohols, more preferably C1-C5 monohydric alcohols, and most preferably any one or at least a combination of two of methanol, ethanol and acetone.

[0030] Preferably, the nanoparticles are selected from any one or at least a combination of two of nano-silica, carbon nanotubes, carbon nanofibers and graphene sheets;

[0031] Preferably, the mass ratio of the nanoparticles to the blended fabric containing the silicon-oxygen chains is (1:100)-(1:200).

[0032] Secondly, the present invention provides a modified basalt fiber fabric, which is prepared by the modified basalt fiber fabric preparation method described in the foregoing embodiments.

[0033] Thirdly, the present invention provides a basalt fiber composite material, which includes the modified basalt fiber fabric described in the foregoing embodiments.

[0034] Fourthly, the present invention provides a method for preparing a basalt fiber composite material, comprising: stacking the above-mentioned modified basalt fiber fabric and then hot-pressing it.

[0035] In an optional implementation, the modified basalt fiber fabric is stacked in alternating longitudinal and transverse layers.

[0036] Preferably, the total number of layers is 5-20.

[0037] In an optional implementation, the hot pressing conditions include: a temperature of 160-220°C, a pressure of 1-5 MPa, and a time of 0.5-2 hours.

[0038] The present invention has the following beneficial effects: (1) The embodiments of the present invention can maximize the wettability between basalt fiber cloth and thermoplastic resin by forming a hybrid woven fabric, and reduce the structural defects of the related composite material after hot pressing. At the same time, the interface compatibilization modification between basalt fiber and resin is changed, and the interface strength and mechanical properties of the modified basalt fiber fabric can be further improved through activation, chemical grafting and loading.

[0039] (2) By first forming a woven composite and then performing surface modification, the processing difficulty of basalt fiber reinforced thermoplastic composites is reduced, and the interfacial properties and mechanical strength of the composites are improved. Specifically, the inorganic nanoparticles introduced into the basalt fiber woven composite increase the roughness between the composite and the thermoplastic resin, achieving mechanical interlocking and solving the problem of low interfacial strength of the composite material.

[0040] (3) The modified basalt fiber fabric has the advantages of high stability, good impact resistance, green and environmentally friendly production process, and recyclability.

[0041] (4) Basalt fiber composite materials can be processed and applied in various fields to prepare different shaped parts, expand their applications, and achieve the goal of widespread use. Attached Figure Description

[0042] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0043] Figure 1 A schematic diagram of the preparation process of basalt fiber composite material provided in an embodiment of the present invention;

[0044] Figure 2 This is a diagram illustrating the weaving method of the mixed-knit fabric provided in an embodiment of the present invention;

[0045] Figures 3-4 The surface topography diagram provided for an embodiment of the present invention. Detailed Implementation

[0046] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0047] Basalt fiber is an inorganic fiber primarily composed of silica. Its smooth and chemically inert surface makes it difficult to form mechanical or chemical bonds with resin, resulting in poor wettability and bonding between basalt fiber and resin. This is particularly pronounced in basalt fiber-reinforced thermoplastic resin composites. Achieving sufficient wetting and uniform bonding between basalt fiber and thermoplastic resin in the face of high-viscosity molten thermoplastic resin is challenging, placing extremely high demands on processing techniques and significantly weakening the reinforcing effect of basalt fiber on the thermoplastic resin matrix. Furthermore, the weak interfacial interactions between basalt fiber and thermoplastic resin prevent the overall performance of basalt fiber-reinforced thermoplastic composites from meeting the requirements of various applications, severely restricting their development and application. Therefore, improving the wettability between basalt fiber and thermoplastic resin, reducing the processing difficulty of related composites, and effectively enhancing the interfacial adhesion and mechanical properties between basalt fiber and thermoplastic resin have become the main directions for the future development of basalt fiber composites.

[0048] Most of the existing methods for improving the interfacial properties of basalt fiber composites involve using short basalt fibers to reinforce thermoplastic resin to form granules, which are then hot-pressed to prepare the composite material. Alternatively, long basalt fibers can be used to wrap thermoplastic resin, and the two can be combined to form a composite material. However, these methods cannot preserve the warp and weft arrangement of the fiber fabric and are difficult to apply in practice.

[0049] To address the aforementioned problems, this invention provides a method for preparing modified basalt fiber fabric, the preparation process of which is described below. Figure 1 Specifically, it includes:

[0050] S1, forming a mixed woven fabric;

[0051] Basalt fiber and thermoplastic fiber are mixed and woven together (see weaving method). Figure 2 , Figure 2 The letter 'a' indicates a weaving method where basalt fibers are in the weft direction and thermoplastic fibers are in the warp direction. Figure 2 In the diagram, 'b' indicates a weft yarn configuration where basalt fiber is used as the weft and thermoplastic fiber and basalt fiber are used together as the warp yarn. The basalt fiber monofilaments are 100-150 tex, and the weft yarn has a size of 850-900 D. The thermoplastic fiber, or both thermoplastic fiber and basalt fiber, are used together as the warp yarn, with a size of 900-1300 D and a monofilament size of 100-200 tex.

[0052] The mass ratio of basalt fiber to thermoplastic fiber is (7:3)-(6:4); for example, it is any value between (7:3)-(6:4) or any range between any two values, such as 7:3, 1.8:1, 1.5:1 and 2:1, for example, preferably (1.5:1)-(2:1).

[0053] The weight of the blended fabric is 200-300 g / m². 2 For example, 200g / m 2 210g / m 2 220g / m 2 230g / m 2 240g / m 2 250g / m 2 260g / m 2 270g / m 2 280g / m 2 290g / m 2 and 300g / m 2 200-300g / m 2 Any value between two values ​​or a range between any two values.

[0054] Thermoplastic fibers can be selected from existing thermoplastic fibers, such as, but not limited to, polypropylene fibers, polyethylene fibers, polyester fibers, and nylon fibers.

[0055] This invention, through the formation of a hybrid woven fabric from basalt fiber and thermoplastic fiber, maximizes the wettability between the continuous basalt fiber cloth and the thermoplastic resin, reducing structural defects after hot pressing of the composite material. Simultaneously, this hybrid woven fabric directly performs interfacial compatibilization modification between the fiber and resin, facilitating subsequent modification, improving interfacial properties, and consequently enhancing the mechanical properties of the resulting composite material. Furthermore, the hybrid weaving method facilitates the processing of the modified fiber fabric, enabling rapid molding, eliminating pollution, and allowing for the fabrication of various irregular shapes to meet the needs of diverse applications.

[0056] S2, Activation treatment;

[0057] The blended fabric is activated to form silanol groups on its surface. Specifically, the blended fabric, organic solvent, and water are mixed and ultrasonically treated to remove the sizing agent from the surface of the basalt fiber fabric and to hydrolyze the surface to generate silanol groups, followed by drying.

[0058] The organic solvent is selected from alcohol solvents and / or ketone solvents, preferably monohydric alcohols, more preferably C1-C5 monohydric alcohols, such as, but not limited to, any one or at least two combinations of methanol, ethanol and acetone.

[0059] The mass of the blended fabric accounts for 40-90% of the total mass of the blended fabric, the organic solvent, and the water; for example, any value between 40% and 90% or any range between any two values, such as 40%, 50%, 60%, 70%, 80%, and 90%.

[0060] The mass ratio of the organic solvent to the water is (3:8) to (3:13); for example, any value between (3:8) and (3:13) or any range between any two values, such as 3:8, 3:9, 3:10, 3:11, 3:12, and 3:13.

[0061] The drying conditions include: a temperature of 40-90℃ and a time of 2-10 hours. For example, the temperature can be any value between 40-90℃ or any range between any two values, such as 40℃, 50℃, 60℃, 70℃, 80℃, and 90℃. The time can be any value between 2-10 hours or any range between any two values, such as 2 hours, 3 hours, 4 hours, 5 hours, 6 hours, 7 hours, 8 hours, 9 hours, and 10 hours.

[0062] S3, chemical grafting;

[0063] Chemical grafting is performed to link silicon-oxygen-silicon chains to the woven fabric. The specific operation is as follows: the activated woven fabric is mixed with a modifier and reacted.

[0064] The modifier is selected from siloxane compounds, preferably any one or at least a combination of two of γ-ureidopropyltriethoxysilane, β-aminoethyl-γ-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, phenylaminomethyltrimethoxysilane and phenylaminomethyltriethoxysilane.

[0065] The mass ratio of the activated blended fabric to the modifier is (4:1.5) to (12:1.5); for example, any value between (4:1.5) and (12:1.5) or any range between any two values, such as 4:1.5, 6:1.5, 7:1.5, 9:1.5, 10:1.5, and 12:1.5.

[0066] The reaction conditions include a temperature of 90-130℃ and a time of 4-6 hours. For example, the temperature can be any value between 90-130℃ or any range between any two values, such as 90℃, 100℃, 110℃, 120℃, and 130℃.

[0067] S4, Load;

[0068] Nanoparticles are loaded onto the hybrid woven fabric containing the silicon oxide chains. Specifically, the hybrid woven fabric containing the silicon oxide chains, the nanoparticles, and a mixed solvent are mixed and then subjected to ultrasound.

[0069] The mixed solvent includes water and an organic solvent, wherein the volume ratio of the water to the organic solvent is (1:1) to (2:5); the organic solvent is selected from alcohol solvents and / or ketone solvents, preferably monohydric alcohols, more preferably C1-C5 monohydric alcohols, such as, but not limited to, any one or at least two combinations of methanol, ethanol and acetone.

[0070] The nanoparticles are selected from any one or at least two combinations of nano-silica, carbon nanotubes, carbon nanofibers and graphene sheets; the mass ratio of the nanoparticles to the woven fabric containing the silicon-oxygen chains is (1:100)-(1:200), for example, 1:150.

[0071] During the ultrasound process, the nanoparticles are evenly dispersed, allowing some nanoparticles to be chemically bonded to the basalt fiber fabric, while others are embedded in the basalt fiber fabric through physical deposition.

[0072] It is evident that blending basalt fibers and thermoplastic fibers improves their compatibility during hot pressing. Then, physical deposition is used to synergistically prepare nanoparticle-containing surfaces, increasing fiber surface roughness and enhancing the interfacial strength between basalt and thermoplastic fibers, thereby improving their mechanical properties. Fiber blending retains the biaxial tensile properties of the fibers while improving the compatibility between basalt fibers and thermoplastic resins. The introduction of nanoparticles creates a mechanical interlock between the basalt fibers and thermoplastic resins, further enhancing interfacial strength and improving the mechanical properties of the composite material. The blended fabric is easy to modify, allowing for organic, inorganic, and organic-inorganic hybrid modifications. The modified preforms are easy to process, quick to form, pollution-free, and can be processed into various irregular shapes to meet the needs of various applications.

[0073] Secondly, the present invention provides a modified basalt fiber fabric, which is prepared by the modified basalt fiber fabric preparation method described in the foregoing embodiments.

[0074] Thirdly, the present invention provides a basalt fiber composite material, which includes the modified basalt fiber fabric described in the foregoing embodiments.

[0075] Fourthly, the present invention provides a method for preparing a basalt fiber composite material, comprising: stacking the above-mentioned modified basalt fiber fabric and then hot-pressing it.

[0076] Specifically, the modified basalt fiber fabric is stacked alternately in both longitudinal and transverse directions, with a total of 5-20 layers. The temperature is 160-220℃, the pressure is 1-5MPa, and the time is 0.5-2 hours.

[0077] In summary, the present invention's method of first forming a hybrid woven fabric and then performing surface modification not only reduces the processing difficulty of basalt fiber reinforced thermoplastic composites but also improves the interfacial properties and mechanical strength of the related composites. The inorganic nanoparticles introduced into the basalt fiber hybrid woven fabric increase its roughness with the thermoplastic resin, achieving mechanical interlocking and solving the problem of low interfacial strength in composite materials. The present invention employs a fiber hybrid weaving method, and through surface modification on the hybrid woven fabric, the composite material made from continuous fibers can maximize the high strength and high modulus mechanical properties of the reinforcement, possessing advantages such as high material stability, good impact resistance, a green and environmentally friendly production process, and recyclability. The basalt fiber and thermoplastic fiber hybrid woven fabric obtained by the present invention can be processed and applied in various fields to prepare different shaped parts, expanding its applications and achieving widespread use.

[0078] The features and performance of the present invention will be further described in detail below with reference to embodiments.

[0079] Example 1

[0080] This invention provides a method for preparing basalt fiber composite materials, comprising:

[0081] S1, forming a mixed woven fabric;

[0082] Basalt fiber is used in the weft direction, while polypropylene fiber and basalt fiber are woven together in the warp direction in a mixed weave, with a mass ratio of basalt fiber to polypropylene fiber of 7:3. The resulting mixed woven fabric has a basis weight of 250 g / m². 2 .

[0083] S2, Activation treatment;

[0084] The blended fabric, ethanol, and deionized water were uniformly mixed in a specific ratio at room temperature and then treated in an ultrasonic machine for 3 hours to remove the sizing agent from the surface of the basalt fiber fabric and to hydrolyze the surface to generate silanol groups. Afterward, the mixture was dried in an oven at 60°C for 3 hours to obtain the pretreated basalt fiber fabric. The blended fabric accounted for 90% of the total mass, and the mass ratio of solvent to deionized water was 3:9.

[0085] S3, chemical grafting;

[0086] Pretreated basalt fiber fabric was mixed uniformly with 3-aminopropyltriethoxysilane in a certain proportion and reacted at 120°C for 2 hours to obtain a basalt fiber fabric system containing grafted chains. The mass ratio of the pretreated basalt fiber fabric to the modifier was 4:1.5.

[0087] S4, Load;

[0088] Nano-SiO2 (purchased from Evonik Degussa, particle size 7-40 nm) was added to the basalt fiber fabric system after chain extension, with a SiO2 mass of 0.5 g. This SiO2 was then added to a mixture of water and ethanol at a volume ratio of 1:2 and ultrasonically dispersed for 60 min at 100 W until the inorganic particles were uniformly dispersed. The mass ratio of inorganic particles to the woven fabric containing the silicon-oxygen chains was 1:150.

[0089] S5, hot pressing;

[0090] A hot-pressing process is used to lay up the basalt fiber woven fabric formed by S4 in a longitudinal and transverse stacking manner. The layers are then placed in a 180°C environment and hot-pressed at 1 MPa for 1 hour. The resulting basalt fiber composite material is then obtained. The total number of layers in the basalt fiber woven fabric is 9.

[0091] Examples 2-5

[0092] Examples 2-5 prepared basalt fiber composite materials according to the preparation method provided in Example 1. The quality of the fiber fabric remained unchanged, the difference being the amount of nano-SiO2 used, as detailed below:

[0093] Example 2: The amount of nano-SiO2 used was 1.0g.

[0094] Example 3: The amount of nano-SiO2 used was 2.0g.

[0095] Example 4: The amount of nano-SiO2 used was 4.0g.

[0096] Example 5: The amount of nano-SiO2 used was 8.0g.

[0097] Example 6

[0098] This invention provides a method for preparing basalt fiber composite materials, comprising:

[0099] S1, forming a mixed woven fabric;

[0100] Basalt fiber is used in the weft direction, and polypropylene fiber is used in the warp direction. The mass ratio of basalt fiber to polypropylene fiber is 6:4, and the resulting blended fabric has a basis weight of 250 g / m². 2 .

[0101] S2, Activation treatment;

[0102] The blended fabric, ethanol, deionized water, and acetone were mixed evenly in proportion at room temperature and then placed in an ultrasonic machine for 4 hours to wash away the sizing agent on the surface of the basalt fiber fabric and to hydrolyze the surface to produce silanol groups. After that, it was placed in an oven at 70°C and dried for 4 hours to obtain the pretreated basalt fiber fabric. The blended fabric accounted for 90% of the total mass, and the mass ratio of solvent to deionized water was 3:8.

[0103] S3, chemical grafting;

[0104] Pretreated basalt fiber fabric was mixed uniformly with β-aminoethyl-γ-aminopropyltrimethoxysilane and reacted at 80°C for 6 hours to obtain a basalt fiber fabric system containing grafted chains. The mass ratio of the pretreated basalt fiber fabric to the modifier was 4:1.5.

[0105] S4, Load;

[0106] Graphene sheets (purchased from Suzhou CarbonFeng Graphene) were added to the basalt fiber fabric system after chain extension, with a mass of 0.5g of graphene sheets. The basalt fiber fabric was then placed in a mixture of water and ethanol (volume ratio 1:2) and ultrasonically dispersed at 100W for 40 minutes until the inorganic particles were uniformly dispersed. The mass ratio of inorganic particles to the woven fabric containing the silicon-oxygen chains was 1:150.

[0107] S5, hot pressing;

[0108] A hot-pressing process is used to lay up the basalt fiber woven fabric formed by S4 in a longitudinal and transverse stacking manner. The layers are then placed in a 190°C environment and hot-pressed at 2 MPa for 1 hour. The resulting basalt fiber composite material is then obtained. The total number of layers in the basalt fiber woven fabric is 5.

[0109] Examples 7-10

[0110] Examples 7-10 describe the preparation of basalt fiber composite materials using the same method as in Example 6, with the same fiber fabric quality. The difference lies in the amount of graphene sheets used, as detailed below:

[0111] Example 7: The amount of graphene sheet used was 1.0g.

[0112] Example 8: The amount of graphene sheet used was 2.0g.

[0113] Example 9: The amount of graphene sheet used was 4.0g.

[0114] Example 10: The amount of graphene sheet used was 8.0g.

[0115] Examples 11-15

[0116] Examples 11-15 were prepared using the same method as in Example 6, with the same fiber fabric quality. The difference lay in the carbon nanotubes used and their amounts, as detailed below:

[0117] Example 11: The amount of carbon nanotubes used was 0.5g.

[0118] Example 12: The amount of carbon nanotubes used was 1.0g.

[0119] Example 13: The amount of carbon nanotubes used was 2.0g.

[0120] Example 14: The amount of carbon nanotubes used was 4.0g.

[0121] Example 15: The amount of carbon nanotubes used was 8.0g.

[0122] Example 16

[0123] This embodiment provides a method for preparing a composite material. The preparation method is the same as that in Example 1, except that the mixing method in this comparative example is as follows: basalt fiber is in the weft direction and polypropylene fiber is in the warp direction.

[0124] Example 17

[0125] This embodiment provides a method for preparing a composite material, which is the same as in Example 1, except that the mass ratio of S1 basalt fiber to polypropylene fiber is 6:4.

[0126] Example 18

[0127] This embodiment provides a method for preparing a composite material, which is the same as that in Example 8, except that the graphene sheet is replaced with an equal amount of nano-SiO2.

[0128] Comparative Example 1

[0129] This comparative example provides a method for preparing a composite material, which is the same as in Example 1, except that S1 is not performed. Instead, basalt fiber fabric and polypropylene resin film are hot-pressed together, wherein the mass ratio of basalt fiber to polypropylene resin is the same as in Example 1.

[0130] Comparative Example 2

[0131] This comparative example provides a method for preparing a composite material, which is the same as in Example 1, except that: instead of S1 and S4, S2 and S3 are used to modify the basalt fiber chopped short fibers. The modified chopped short fibers are then granulated by twin-screw extrusion and injection molding with polypropylene granules. The mass ratio of basalt fiber to polypropylene resin is the same as in Example 1.

[0132] Comparative Example 3

[0133] This comparative example provides a method for preparing a composite material, which is the same as in Example 1, except that nano-SiO2 is replaced with an equal amount of nano-TiO2 (purchased from Evonik Degussa, with a particle size of 7-40 nm).

[0134] Comparative Example 4

[0135] This comparative example provides a method for preparing a composite material, which is the same as in Example 1, except that nano-SiO2 is replaced with an equal amount of nano-ZnO (purchased from Evonik Degussa, with a particle size of 7-40 nm).

[0136] Comparative Example 5

[0137] This comparative example provides a method for preparing a composite material, which differs from Example 8 in that the operation in step S4 is different, as follows:

[0138] S4, chain extension reaction;

[0139] A certain amount of ethylene glycol diglycidyl ether was added to the basalt fiber fabric system that had already undergone chain extension, and the mixture was reacted at 80°C for 2 hours. The basalt fiber fabric was then washed in deionized water for 2 hours, and then dried in an oven at 50°C for 4 hours to obtain the modified basalt fiber fabric. The ethylene glycol diglycidyl ether accounted for 20% of the total mass.

[0140] Comparative Example 6

[0141] This comparative example provides a method for preparing a composite material, which is the same as in Example 8, except that only steps S1, S2 and S5 are performed, and no modification is performed in the rest.

[0142] Test 1

[0143] The tensile strength, flexural strength, impact strength, and interfacial shear strength of Examples 1-15 and Comparative Examples 1-6 were tested. The testing methods are as described in GB / T 1040.1-2018 and GB / T 9341-2000. The results are shown in Tables 1-10.

[0144] Table 1 Mechanical properties of composite materials with different weaving methods

[0145]

[0146] Table 2 Mechanical properties of composite materials with different basalt fiber to resin mass ratios

[0147]

[0148] Table 3 Mechanical properties of composite materials in Examples 1-5

[0149] Performance indicators Example 1 Example 2 Example 3 Example 4 Example 5 Tensile strength (MPa) 201 224 254 221 187 Bending strength (MPa) 210 231 246 214 198 <![CDATA[Impact strength (Kj / m 2 )]]> 38 43 48 44 36

[0150] Table 4 Mechanical properties of composite materials formed from different nanoparticles

[0151]

[0152]

[0153] Table 5 Mechanical properties of composite materials formed by different modification methods

[0154] Performance indicators Comparative Example 7 Comparative Example 5 Comparative Example 6 Example 8 Tensile strength (MPa) 147 160 198 241 Bending strength (MPa) 132 140 197 240 <![CDATA[Impact strength (Kj / m 2 )]]> 28 32 36 46

[0155] Table 6 Mechanical properties of composite materials formed from graphene sheets

[0156] Performance indicators Example 6 Example 7 Example 8 Example 9 Example 10 Tensile strength (MPa) 200 217 241 234 210 Bending strength (MPa) 201 204 240 231 202 <![CDATA[Impact strength (Kj / m 2 )]]> 37 39 46 42 38

[0157] Table 7 Mechanical properties of carbon nanotube-formed composite materials

[0158]

[0159] Table 8 Mechanical properties of composite materials formed by different processing methods

[0160]

[0161]

[0162] Table 9 Mechanical properties of composite materials formed by grafting other different inorganic particles.

[0163] Performance indicators Comparative Example 3 Comparative Example 4 Tensile strength (MPa) 177 181 Bending strength (MPa) 170 175 <![CDATA[Impact strength (Kj / m 2 )]]> 35 36

[0164] Table 10. Interfacial shear strength between monofilament and resin in Examples 1-5

[0165] Performance indicators Example 1 Example 2 Example 3 Example 4 Example 5 IFSS (MPa) 18 22 26 24 21

[0166] Note: The interfacial shear strength between the fiber and resin in each embodiment was measured based on the microdroplet debonding experiment. The test sample was the basalt fiber monofilament in each embodiment. The resin fiber was knotted on the basalt fiber monofilament, then hot-melted, cured, and coated before the debonding experiment was carried out. The IFSS was calculated from the stress-strain curve of the relevant sample.

[0167] Table 11 Interfacial shear strength of fiber monofilaments grafted with different inorganic particles

[0168]

[0169] Note: The interfacial shear strength between the fiber and resin in each embodiment was measured based on the microdroplet debonding experiment. The test sample was the basalt fiber monofilament in each embodiment. The resin fiber was knotted on the basalt fiber monofilament, then hot-melted, cured, and coated before the debonding experiment was carried out. The IFSS was calculated from the stress-strain curve of the relevant sample.

[0170] Table 12 Shear strength of monofilament-resin interface with different modification methods

[0171] Performance indicators Comparative Example 7 Comparative Example 5 Comparative Example 6 Example 8 Tensile strength (MPa) 8 10 22 26

[0172] Note: The interfacial shear strength between the fiber and resin in each embodiment was measured based on the microdroplet debonding experiment. The test sample was the basalt fiber monofilament in each embodiment. The resin fiber was knotted on the basalt fiber monofilament, then hot-melted, cured, and coated before the debonding experiment was carried out. The IFSS was calculated from the stress-strain curve of the relevant sample.

[0173] As shown in Table 1, the mixed weaving method in Example 1 is more conducive to the mechanical properties of basalt fiber reinforced thermoplastic resin.

[0174] Table 2 shows that a resin-to-fiber mass ratio of 3:7 is more effective than a ratio of 4:6.

[0175] As shown in Table 3, adding an appropriate amount of nano-SiO2 can improve the mechanical properties of basalt fiber / thermoplastic resin composites, but excessive inorganic particles will reduce them. This is attributed to the excessive stacking of inorganic particles, which causes stress concentration.

[0176] As shown in Table 4, under the same conditions, carbon nanotubes have a better reinforcing effect than nano-SiO2, which is better than graphene sheets.

[0177] Table 5 shows that the mechanical properties of organic chain modified basalt fiber surface-reinforced thermoplastic resin composites are not good. After further organic-inorganic hybrid modification, the mechanical properties show an increase, but the effect is best when only inorganic particles are used for loading.

[0178] As shown in Table 6, adding an appropriate amount of graphene sheets can improve the mechanical properties of basalt fiber / thermoplastic resin composites, but excessive inorganic particles will reduce them. This is attributed to the excessive stacking of inorganic particles, which causes stress concentration.

[0179] As shown in Table 7, adding an appropriate amount of carbon nanotubes can improve the mechanical properties of basalt fiber / thermoplastic resin composites, but excessive inorganic particles will reduce them. This is attributed to the excessive stacking of inorganic particles, which causes stress concentration.

[0180] As shown in Table 8, compared with the traditional twin-screw extrusion process and the film lamination hot pressing process, the basalt fiber fabric after this method has the best mechanical properties, proving that this method can improve the compatibility between basalt fiber and thermoplastic resin.

[0181] As shown in Table 9, the inorganic particles in Comparative Examples 3 and 4 did not have a better effect on the mechanical properties of the composite materials than the selected silica, carbon nanotubes, and graphene sheets.

[0182] As shown in Table 10, the interfacial shear strength and mechanical properties of basalt fibers after inorganic particle loading show the same trend with thermoplastic resin.

[0183] As shown in Table 11, the interfacial shear strength and mechanical properties of basalt fibers after inorganic particle loading show the same trend with thermoplastic resin, and carbon nanotubes have a better effect.

[0184] As shown in Table 12, the interfacial shear strength and mechanical properties of basalt fiber and thermoplastic resin before and after modification show the same trend, and the modified samples all show significant improvement.

[0185] Detection Example 2

[0186] Electron microscopy was performed on the surface of Example 1 before and after surface modification to obtain surface morphology images. The results are shown in [reference]. Figure 3 and Figure 4 .in Figure 3 In the text, 'a' represents unmodified basalt fiber. Figure 3 In the middle, b represents the basalt fiber surface that has completed the S3 step of grafting. Figure 3 In the figure, 'c' represents the basalt fiber surface that has completed the S4 loading. Figure 3 In the figure, 'd' represents the basalt fiber surface grafted with more inorganic particles. Electron microscopy scans were performed on the surfaces of Examples 3, 8, and 13 before and after surface modification to obtain their surface morphology images. Figure 4 In the image, 'a' represents the surface morphology of grafted inorganic particles, specifically nano-SiO2. Figure 4 In the image, b represents the surface morphology of a graphene sheet grafted with inorganic particles. Figure 4 The 'c' in the figure represents the surface morphology of the grafted inorganic particles, which are carbon nanotubes.

[0187] according to Figure 3 and Figure 4 It can be seen that inorganic particles were successfully loaded onto the surface of basalt fibers. As the number of inorganic particles increases, they begin to aggregate, which leads to stress concentration and has an adverse effect on mechanical properties. Figure 3 The surface of basalt fiber is very smooth, and its chemical composition is inert, which is not conducive to its bonding with thermoplastic resin. Figure 3 In component b, a relatively dense organic layer forms on the surface, which is the grafted silane coupling agent. Figure 3 In section c, after loading with S4, an inorganic nanoparticle layer was grafted and deposited on the surface, proving that the grafting was successful. Figure 3 In the middle d, a large number of inorganic particles adhere to the surface of basalt fibers, which can easily lead to stress concentration and a decline in mechanical properties after the composite material is formed. Figure 4 In the image, we can see that nano-SiO2, graphene sheets, and carbon nanotubes exhibit the following shapes: spherical, sheet-like, and network structures, respectively.

[0188] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for preparing a basalt fiber composite material, characterized in that, include: Basalt fiber and thermoplastic fiber are mixed and woven to form a mixed woven fabric; wherein, during the mixed weaving process, the basalt fiber is the weft direction, and the thermoplastic fiber and the basalt fiber together serve as the warp direction; Then, the blended fabric is activated to form silanol groups on the surface of the blended fabric. The activation treatment step includes: mixing the blended fabric, organic solvent, and water, followed by ultrasonication and then drying; the organic solvent is selected from alcohol solvents and / or ketone solvents. Next, chemical grafting is performed to link silicon-oxygen chains to the woven fabric; wherein the activated woven fabric is mixed with a modifier and reacted; the modifier is selected from siloxane compounds; Then, nanoparticles are loaded onto the woven fabric containing the silicon oxide chains to obtain a modified basalt fiber fabric; wherein the nanoparticles are selected from any one of nano-silica, carbon nanotubes and graphene sheets. The modified basalt fiber fabrics are then stacked and hot-pressed.

2. The preparation method according to claim 1, characterized in that, The mass ratio of the basalt fiber to the thermoplastic fiber is (7:3)-(6:4). And / or, the blended fabric has a weight of 200-300 g / m 2 .

3. The preparation method according to claim 1, characterized in that, The organic solvent is a monohydric alcohol.

4. The preparation method according to claim 1, characterized in that, The organic solvent is a C1-C5 monohydric alcohol.

5. The preparation method according to claim 1, characterized in that, The organic solvent is any one or a combination of at least two of methanol, ethanol and acetone.

6. The preparation method according to claim 1, characterized in that, The mass of the blended fabric accounts for 40-90% of the total mass of the blended fabric, the organic solvent, and the water; And / or, the mass ratio of the organic solvent to the water is (3:8) to (3:13); And / or, drying conditions include: a temperature of 40-90°C and a time of 2-10 hours.

7. The preparation method according to claim 1, characterized in that, The side groups of the silicon-oxygen chain are amino groups.

8. The preparation method according to claim 1, characterized in that, The modifier is any one or at least a combination of two of γ-ureidopropyltriethoxysilane, β-aminoethyl-γ-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, phenylaminomethyltrimethoxysilane, and phenylaminomethyltriethoxysilane. And / or, the mass ratio of the activated blended fabric to the modifier is (4:1.5) to (12:1.5). And / or, the reaction conditions include: a temperature of 90-130℃ and a time of 4-6 hours.

9. The preparation method according to claim 1, characterized in that, The step of loading the nanoparticles includes: mixing the woven fabric containing the silicon oxide chains, the nanoparticles, and a mixed solvent, and then sonicating them.

10. The preparation method according to claim 9, characterized in that, The mixed solvent includes water and an organic solvent, wherein the volume ratio of the water to the organic solvent is (1:1) to (2:5). And / or, the mass ratio of the nanoparticles to the blended fabric containing the silicon-oxygen chains is (1:100) to (1:200).

11. The preparation method according to claim 1, characterized in that, The modified basalt fiber fabric is stacked in alternating layers.

12. The preparation method according to claim 11, characterized in that, The total number of stacked layers is 5-20.

13. The preparation method according to claim 1, characterized in that, The conditions for hot pressing include: temperature of 160-220℃, pressure of 1-5MPa, and time of 0.5-2 hours.

14. A basalt fiber composite material, characterized in that, It is prepared by the method for preparing basalt fiber composite material according to any one of claims 1-13.

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