Basalt fiber reinforced material for wind power blade and preparation method of basalt fiber reinforced material

Abstract

The invention discloses a basalt fiber reinforced material for a wind power blade and a preparation method of the basalt fiber reinforced material, and belongs to the technical field of wind power blade materials. The basalt fiber reinforced material for the wind power blade is prepared from the following components in parts by weight: 90 to 94 parts of basalt fiber, 4 to 8 parts of sulfonated polyetheretherketone, 3 to 5 parts of modified hollow glass microspheres and 0.2 to 0.5 part of graphene oxide. According to the invention, a ternary synergistic multistage composite interface layer is constructed on the surface of the continuous basalt fiber, and low-density hollow microspheres and a high-modulus graphene oxide network are organically combined, so that the density of the interface layer is obviously reduced and the rigidity is synchronously improved; therefore, the specific modulus of the prepared basalt fiber reinforced material is improved, and the technical problem that traditional basalt fibers are high in density and difficult to meet the extremely lightweight design requirement of ultra-large wind power blade tips is effectively solved.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of wind power blade materials, and particularly relates to a basalt fiber reinforced material for a wind power blade and a preparation method thereof. BACKGROUND

[0002] Wind power generation is accelerating towards the direction of "large megawatt, super long blade and deep sea". The increase in the length of the wind power generation blade will inevitably lead to a cubic level increase in the mass. The increase in the mass of the blade, especially the accumulation of the mass of the blade tip, will significantly increase the moment of inertia, increase the starting wind speed threshold of the unit, and generate a huge fatigue load on the hub and the tower. Therefore, the development of a reinforced material with "lightweight" and "high modulus" is the key to solving the above problems.

[0003] At present, the reinforced material for wind power blades mainly uses glass fiber and carbon fiber. However, the modulus of glass fiber is low (about 72 GPa), which is difficult to meet the stiffness requirement of super long blades; although carbon fiber has excellent performance, it has high cost and lightning risk.

[0004] Basalt fiber, as a kind of natural mineral fiber, has a modulus and corrosion resistance better than glass fiber; in order to improve the performance of basalt fiber in composite materials, the existing technology mainly focuses on improving the interfacial bonding strength between the basalt fiber and the resin matrix through surface modification, but these methods have obvious defects in solving the specific modulus problem.

[0005] The existing technology such as CN116813980A discloses a modified basalt fiber, a preparation method thereof and a basalt fiber reinforced epoxy resin composite material, which grafts nano-SiO2, TiO2 or carbon nanotubes to the surface of basalt fiber by using a silane coupling agent; and CN107200867A discloses a preparation method and application of a basalt fiber surface nano-coated multi-scale reinforcing body, which coats nano-particles by using a KH550 / KH560 coupling agent.

[0006] The above-mentioned existing technologies generally graft or coat solid inorganic nano-particles to the surface of basalt fiber to increase the surface roughness and chemical activity. Although the interfacial shear strength is improved by mechanical engagement or chemical bonding, the introduced particles are high-density solid inorganic particles (the density of SiO2 is about 2.2 g / cm 3 , and the density of TiO2 is about 4.2 g / cm 3 ). This operation increases the equivalent density of the interface layer in the microcosmic view, and cannot solve or even exacerbate the problem of high density of basalt fiber, which is difficult to meet the demand for extreme lightweight of super long blades.

[0007] Wind power blades are also often used in high-humidity and hot environments such as offshore, and the existing technology tries to use special engineering plastics as sizing agent matrix in order to match high-performance thermoplastic resin or improve temperature resistance. For example, CN118461329A discloses a method for improving the interface performance of basalt fiber reinforced thermoplastic resin-based composite material. The technical solution uses amino polyether sulfone and cooperates with acidified carbon nanotubes to perform sizing treatment on basalt fibers.

[0008] However, the above technical solution only uses the rigidity of polyether sulfone skeleton and the reinforcing effect of carbon nanotubes, and the technical concept is limited to strengthening and heat resistance, without considering the introduction of physical weight reduction units in the interface layer. The interface layer prepared by the above technical solution is still a dense solid structure, which cannot significantly reduce the specific gravity of the material while maintaining high modulus.

[0009] Attempts have been made to modify the porous structure in some fields, but they are not usually used for structural reinforcement. For example, CN119080535A discloses a nano-SiO2 modified basalt fiber material and a preparation method thereof. In the above technical solution, porous silica particles are also introduced for interlayer toughening, but the use of porous particles is for toughening, which will sacrifice the rigidity of the material. For example, CN119019816A discloses a basalt-based shielding material and a preparation method thereof, which uses PMMA microspheres as a sacrificial template to manufacture three-dimensional porous carbon fibers for electromagnetic shielding. The main purpose of this technical solution is to construct a conductive network or wave-absorbing structure.

[0010] The skilled in the art generally believe that the introduction of hollow or porous structure in the interface layer of the load-bearing structure will introduce defects, leading to stress concentration, thereby significantly reducing the modulus and strength of the composite material.

[0011] Therefore, the existing technology lacks a basalt fiber reinforced material that can significantly reduce the equivalent density of the interface layer without sacrificing or even improving the rigidity of the basalt fiber. SUMMARY

[0012] To solve the defects in the above technical solution, the purpose of the present application is to provide a basalt fiber reinforced material for wind power blades and a preparation method thereof.

[0013] To achieve the above purpose, the present application provides a basalt fiber reinforced material for wind power blades, which comprises, by weight fraction, 90-94 parts of basalt fiber, 4-8 parts of sulfonated polyether ether ketone, 3-5 parts of modified hollow glass microspheres, and 0.2-0.5 parts of graphene oxide. The basalt fiber is a continuous basalt fiber roving of drawing grade, with a single filament diameter of 13±1μm and a density of 2.65g / cm 3 ; The hollow glass microspheres are high-strength borosilicate microspheres with an average particle size of 5-15 μm, a true density of 0.60 g / cm³, and a compressive strength of >60 MPa. They were purchased from 3M. The graphene oxide is a single-layer graphene oxide with a sheet diameter of 0.5~5μm.

[0014] The sulfonated polyether ether ketone was prepared by the following method: Polyether ether ketone powder was dried in a vacuum oven at 120°C for 6 hours to remove adsorbed moisture; then, 150 mL of 98% concentrated sulfuric acid was added to a 500 mL three-necked flask equipped with a mechanical stirrer, condenser, and thermometer; under stirring, 15 g of the dried polyether ether ketone powder was slowly added in batches to the concentrated sulfuric acid. After the powder was completely dissolved, the reaction system was heated to 50°C and stirred at a constant temperature for 5 hours to perform sulfonation treatment; after the reaction was completed, the reaction solution was slowly poured into a 2000 mL ice-water mixture, resulting in the precipitation of white strip-shaped precipitates; the precipitate was collected by filtration and repeatedly washed with deionized water until the pH of the filtrate was neutral; finally, the washed product was dried in a vacuum oven at 80°C for 24 hours to obtain sulfonated polyether ether ketone solid powder.

[0015] The modified hollow glass microspheres were prepared by the following method: 100g of hollow glass microspheres were weighed and dispersed in 500mL of a mixed solvent of ethanol and water at a volume ratio of 95:5; then glacial acetic acid was added to adjust the pH of the solution to 4.5-5.5, and the mixture was stirred for 15 minutes for surface activation; subsequently, under stirring, a total of 3.0g of N-phenyl-3-aminopropyltrimethoxysilane was slowly added dropwise to the suspension. After the addition was complete, the system was heated to 75℃ and refluxed with mechanical stirring for 6 hours to allow the coupling agent to be fully hydrolyzed and grafted onto the surface of the hollow glass microspheres; after the reaction, the solid product was collected by centrifugation and washed three times with anhydrous ethanol to remove unreacted coupling agent residue. Finally, the washed product was placed in a 110℃ forced-air drying oven for 2 hours to promote the dehydration condensation of silanol groups, thus obtaining modified hollow glass microspheres with phenylamino groups on the surface.

[0016] The CAS number of the N-phenyl-3-aminopropyltrimethoxysilane is 3068-76-6; A method for preparing basalt fiber reinforced material for wind turbine blades includes the following steps: Step A: Preparation of synergistic sizing agent: Weigh 4g of sulfonated polyether ether ketone powder and dissolve it in 96g of N,N-dimethylformamide to prepare a matrix solution; add 0.2g of graphene oxide to the matrix solution and ultrasonically disperse for 30 minutes. Utilize the π-π conjugation between the benzene rings on the sulfonated polyether ether ketone molecular chain and the graphene oxide sheets to form a stable nano-reinforced network; add 3g of modified hollow glass microspheres to the above dispersion and mechanically stir at a high shear rate of 2000rpm for 60 minutes to allow the phenylamino groups on the surface of the modified microspheres to undergo acid-base interaction and π-π stacking with the sulfonic acid groups on the sulfonated polyether ether ketone, forming a uniform and stable ternary synergistic sizing agent suspension.

[0017] Step B: Fiber Impregnation and Forming: 90g of basalt fiber is introduced into a continuous impregnation production line; the traction speed is controlled at 1.5m / min, allowing the basalt fiber to pass through an impregnation tank containing the synergistic sizing agent prepared in Step A, and the sizing amount is controlled by an extrusion roller to ensure that the dispersion fully wets the interior of the fiber bundle; the impregnated fiber is then subjected to gradient drying and curing in three temperature-controlled zones: first, it passes through an 85℃ pre-drying zone to remove most of the solvent from the surface; then it enters a 120℃ vacuum drying zone to remove residual solvent from the micropores; finally, it is treated in a 155℃ heat-setting zone for 5 minutes to allow the sulfonated polyether ether ketone to undergo physical cross-linking and solidify into a film, firmly anchoring the modified hollow glass microspheres and graphene oxide onto the fiber surface; finally, after cooling and winding, a basalt fiber reinforcement material for wind turbine blades is obtained.

[0018] The beneficial effects of this invention are: 1. This invention constructs a ternary synergistic multi-level composite interface layer on the surface of continuous basalt fibers, organically combining low-density hollow microspheres with a high-modulus graphene oxide network, achieving a significant reduction in interface layer density and a simultaneous increase in rigidity, thereby improving the specific modulus of the prepared basalt fiber reinforced material. This effectively solves the technical problem that traditional basalt fibers have a high density and cannot meet the requirements of ultra-lightweight design for the tips of ultra-large wind turbine blades. 2. This invention introduces N-phenyl-3-aminopropyltrimethoxysilane containing a rigid benzene ring structure as a special molecular bridge. By utilizing the acid-base ionic bonding between its secondary amine group and the sulfonated polyether ether ketone matrix, as well as the strong π−π stacking effect between the benzene ring and the sulfonated polyether ether ketone skeleton and graphene oxide sheets, a continuous and dense aromatic rigid network is constructed on the micro-interface. This unique chemical bonding and physical interlocking synergistic mechanism not only effectively overcomes the problem of interfacial stress concentration and delamination caused by hollow microspheres as heterogeneous phases, but also endows the interfacial layer with excellent load transfer efficiency, ensuring the structural stability of the composite material under long-term fatigue load; 3. This invention utilizes the large-volume steric hindrance effect and hydrophobic properties of the benzene ring in phenylaminosilane to construct a dense shield on the surface of hydrophilic hollow glass microspheres. This effectively blocks the hydrolytic erosion path of the silicon-oxygen bond by moisture and humid heat environment, and solves the inherent defect of poor resistance to humid heat aging of traditional aliphatic coupling agents. As a result, the interlaminar shear strength retention rate of the composite material can still be maintained at more than 90% after undergoing harsh humid heat aging tests, which significantly improves the service life and reliability of wind turbine blades in the high humidity and salt spray environment at sea. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. The illustrative embodiments and descriptions of this invention are for explanation only and are not intended to limit the invention. Furthermore, regarding numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Any stated value or intermediate value within a stated range, as well as each smaller range between any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0020] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0021] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be obvious to those skilled in the art. This specification and embodiments are merely exemplary.

[0022] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0023] Example 1 A basalt fiber reinforcement material for wind turbine blades, by weight, comprises the following: 90 parts basalt fiber, 4 parts sulfonated polyether ether ketone, 3 parts modified hollow glass microspheres, and 0.2 parts graphene oxide. The basalt fiber is a continuous basalt fiber roving of drawing grade, with a single filament diameter of 13±1μm and a density of 2.65g / cm³.3 ; The hollow glass microspheres are high-strength borosilicate microspheres with an average particle size of 5-15 μm, a true density of 0.60 g / cm³, and a compressive strength of >60 MPa. They were purchased from 3M. The CAS number of the N-phenyl-3-aminopropyltrimethoxysilane is 3068-76-6; The graphene oxide is a single-layer graphene oxide with a sheet diameter of 0.5~5μm.

[0024] The sulfonated polyether ether ketone was prepared by the following method: Polyether ether ketone powder was dried in a vacuum oven at 120°C for 6 hours to remove adsorbed moisture; then, 150 mL of 98% concentrated sulfuric acid was added to a 500 mL three-necked flask equipped with a mechanical stirrer, condenser, and thermometer; under stirring, 15 g of the dried polyether ether ketone powder was slowly added in batches to the concentrated sulfuric acid. After the powder was completely dissolved, the reaction system was heated to 50°C and stirred at a constant temperature for 5 hours to perform sulfonation treatment; after the reaction was completed, the reaction solution was slowly poured into a 2000 mL ice-water mixture, resulting in the precipitation of white strip-shaped precipitates; the precipitate was collected by filtration and repeatedly washed with deionized water until the pH of the filtrate was neutral; finally, the washed product was dried in a vacuum oven at 80°C for 24 hours to obtain sulfonated polyether ether ketone solid powder.

[0025] The modified hollow glass microspheres were prepared by the following method: 100g of hollow glass microspheres were weighed and dispersed in 500mL of a mixed solvent of ethanol and water with a volume ratio of 95:5; then glacial acetic acid was added to adjust the pH of the solution to 4.5~5.5, and the solution was stirred for 15 minutes to activate the surface.

[0026] Subsequently, under stirring, a total of 3.0 g of N-phenyl-3-aminopropyltrimethoxysilane was slowly added dropwise to the suspension. After the addition was complete, the system was heated to 75°C and the reaction was carried out under mechanical stirring and reflux for 6 hours to allow the coupling agent to be fully hydrolyzed and grafted onto the surface of the hollow glass microspheres. After the reaction was completed, the solid product was collected by centrifugation and washed three times with anhydrous ethanol to remove unreacted coupling agent residue. Finally, the washed product was placed in a 110℃ forced-air drying oven for 2 hours to promote the dehydration condensation of silanol groups, thus preparing modified hollow glass microspheres with active phenylamino groups on the surface.

[0027] A method for preparing basalt fiber reinforced material for wind turbine blades includes the following steps: Step A: Preparation of synergistic sizing agent: Weigh 4g of sulfonated polyether ether ketone powder and dissolve it in 96g of N,N-dimethylformamide to prepare a matrix solution; add 0.2g of graphene oxide to the matrix solution and ultrasonically disperse for 30 minutes. Utilize the π-π conjugation between the benzene rings on the sulfonated polyether ether ketone molecular chain and the graphene oxide sheets to form a stable nano-reinforced network; add 3g of modified hollow glass microspheres to the above dispersion and mechanically stir at a high shear rate of 2000rpm for 60 minutes to allow the phenylamino groups on the surface of the modified microspheres to undergo acid-base interaction and π-π stacking with the sulfonic acid groups on the sulfonated polyether ether ketone, forming a uniform and stable ternary synergistic sizing agent suspension.

[0028] Step B: Fiber Impregnation and Forming: 90g of basalt fiber is introduced into a continuous impregnation production line; the traction speed is controlled at 1.5m / min, allowing the basalt fiber to pass through an impregnation tank containing the synergistic sizing agent prepared in Step A, and the sizing amount is controlled by an extrusion roller to ensure that the dispersion fully wets the interior of the fiber bundle; the impregnated fiber is then subjected to gradient drying and curing in three temperature-controlled zones: first, it passes through an 85℃ pre-drying zone to remove most of the solvent from the surface; then it enters a 120℃ vacuum drying zone to remove residual solvent from the micropores; finally, it is treated in a 155℃ heat-setting zone for 5 minutes to allow the sulfonated polyether ether ketone to undergo physical cross-linking and solidify into a film, firmly anchoring the modified hollow glass microspheres and graphene oxide onto the fiber surface; finally, after cooling and winding, a basalt fiber reinforcement material for wind turbine blades is obtained.

[0029] Example 2 A basalt fiber reinforcement material for wind turbine blades, by weight, comprises the following: 91 parts basalt fiber, 5 parts sulfonated polyether ether ketone, 3.5 parts modified hollow glass microspheres, and 0.3 parts graphene oxide. The preparation methods of sulfonated polyether ether ketone, modified hollow glass microspheres, and basalt fiber reinforced materials for wind turbine blades in Example 2 are all consistent with those in Example 1.

[0030] Example 3 A basalt fiber reinforcement material for wind turbine blades, by weight, comprises the following: 92 parts basalt fiber, 6 parts sulfonated polyether ether ketone, 4 parts modified hollow glass microspheres, and 0.4 parts graphene oxide. The preparation methods of sulfonated polyether ether ketone, modified hollow glass microspheres, and basalt fiber reinforced materials for wind turbine blades in Example 3 are all consistent with those in Example 1.

[0031] Example 4 A basalt fiber reinforcement material for wind turbine blades, by weight, comprises the following: 93 parts basalt fiber, 7 parts sulfonated polyether ether ketone, 4.5 parts modified hollow glass microspheres, and 0.4 parts graphene oxide. The preparation methods of sulfonated polyether ether ketone, modified hollow glass microspheres, and basalt fiber reinforced materials for wind turbine blades in Example 4 are all consistent with those in Example 1.

[0032] Example 5 A basalt fiber reinforcement material for wind turbine blades, by weight, comprises the following: 94 parts basalt fiber, 8 parts sulfonated polyether ether ketone, 5 parts modified hollow glass microspheres, and 0.5 parts graphene oxide. The preparation methods of sulfonated polyether ether ketone, modified hollow glass microspheres, and basalt fiber reinforced materials for wind turbine blades in Example 5 are all consistent with those in Example 1.

[0033] Comparative Example 1 A basalt fiber reinforced material for wind turbine blades, by weight, comprises the following: 92 parts basalt fiber, 6.4 parts sulfonated polyether ether ketone, and 4 parts modified hollow glass microspheres.

[0034] The difference between Comparative Example 1 and Example 3 is that graphene oxide was not added; instead, 0.4 parts of graphene oxide in the original formula were replaced with an equal amount of sulfonated polyether ether ketone.

[0035] Apart from the above, the other components in Comparative Example 1, their preparation methods, and the preparation process of the reinforcing material are all the same as in Example 3.

[0036] Comparative Example 2 A basalt fiber reinforcement material for wind turbine blades, by weight, comprises the following: 92 parts basalt fiber, 6 parts sulfonated polyether ether ketone, 4.0 parts modified hollow glass microspheres, and 1.2 parts graphene oxide.

[0037] The difference between Comparative Example 2 and Example 3 is that the amount of graphene oxide used is increased to 1.2 parts.

[0038] Apart from the above, the other components in Comparative Example 2, their preparation methods, and the preparation process of the reinforcing material are all the same as in Example 3.

[0039] Comparative Example 3 A basalt fiber reinforcement material for wind turbine blades, by weight, comprises the following: 92 parts basalt fiber, 6.0 parts sulfonated polyether ether ketone, 4.0 parts modified solid nano silica, and 0.4 parts graphene oxide.

[0040] The difference between Comparative Example 3 and Example 3 is that solid nano-silica of equal mass with an average particle size of 50 nm was used instead of modified hollow glass microspheres; and the nano-silica was also surface-treated with N-phenyl-3-aminopropyltrimethoxysilane.

[0041] Apart from the above, the other components in Comparative Example 3, their preparation methods, and the preparation process of the reinforcing material are all the same as in Example 3.

[0042] Comparative Example 4 A basalt fiber reinforcement material for wind turbine blades, by weight, comprises the following: 92 parts basalt fiber, 6 parts sulfonated polyether ether ketone, 4 parts KH550 modified hollow glass microspheres, and 0.4 parts graphene oxide. The difference between Comparative Example 4 and Example 3 is that the surface modifier of the hollow glass microspheres is replaced with KH550.

[0043] Apart from the above, the other components in Comparative Example 4, their preparation methods, and the preparation process of the reinforcing material are all the same as in Example 3.

[0044] Comparative Example 5 A basalt fiber reinforcement material for wind turbine blades, by weight, comprises the following: 92 parts basalt fiber, 6 parts sulfonated polyether ether ketone, 4 parts hollow glass microspheres, and 0.4 parts graphene oxide. The difference between Comparative Example 5 and Example 3 is that the hollow glass microspheres were not modified in any way.

[0045] Apart from the above, the other components in Comparative Example 5, their preparation methods, and the preparation process of the reinforcing material are all the same as in Example 3.

[0046] Comparative Example 6 A basalt fiber reinforcement material for wind turbine blades, by weight, comprises the following: 92 parts basalt fiber, 6 parts polyetheretherketone, 4 parts modified hollow glass microspheres, and 0.4 parts graphene oxide. The difference between Comparative Example 6 and Example 3 is that the polyetheretherketone powder was applied directly without any modification treatment.

[0047] Apart from the above, the other components in Comparative Example 6, their preparation methods, and the preparation process of the reinforcing material are all the same as in Example 3.

[0048] Test case The basalt fiber reinforced materials prepared in Examples 1-5 and Comparative Examples 1-8 were uniformly molded into standard unidirectional composite material plates using a compression molding process. These plates were then cut into standard strips of corresponding sizes and subjected to the following performance tests.

[0049] Specific modulus test: The tensile modulus (E, GPa) was determined using an electronic universal testing machine (loading speed 2 mm / min) according to GB / T1447-2005 "Test Method for Tensile Properties of Fiber Reinforced Plastics". The density (ρ, g / cm³) of the composite material sheet was determined using the Archimedes displacement method.

[0050] Specific modulus = Tensile modulus / Density (unit: 10) 6 (m² / s²). The higher this index, the greater the stiffness provided by the material for the same weight.

[0051] Interlaminar shear strength test: Referencing JC / T773-2010 "Test Method for Interlaminar Shear Strength of Fiber Reinforced Plastics", the specimen size was 20mm × 6mm × 2mm, the span was 10mm, and the loading speed was 1mm / min. The interlaminar shear strength of the composite material sheets prepared in Examples 1-5 and Comparative Examples 1-8 were tested.

[0052] Moist heat aging resistance test: Referring to GB / T2573-2008 "Test method for water resistance of glass fiber reinforced plastics", the prepared sample was completely immersed in deionized water at 80℃ and soaked at a constant temperature for 168 hours to accelerate aging.

[0053] After removing and drying the surface moisture, the interlaminar shear strength test was performed again, and then the interlaminar shear strength retention rate after the damp heat aging test was calculated.

[0054] The test results are shown in Table 1: Table 1 Performance test data analysis: As shown in Table 1, the basalt fiber reinforced materials prepared in Examples 1-5 of this invention exhibit excellent balance and superior comprehensive performance across all test dimensions. Furthermore, Example 3 of this application demonstrates the most outstanding performance advantage, with a specific modulus reaching 51.7 × 10⁻⁶. 6 m² / s².

[0055] This invention introduces a large number of modified hollow glass microspheres into the micro-interface layer to construct a physical weight-reducing airbag. This not only avoids the loss of rigidity, but also achieves effective modulus compensation through the rigid aromatic network constructed by the technical solution of this application. This successfully solves the long-standing contradiction between lightweight and high rigidity in the field of wind turbine blades.

[0056] Furthermore, the initial interlaminar shear strength of Examples 1-5 remained above 74 MPa, and after undergoing a rigorous 80℃ / 168h damp heat aging test, the strength retention rate was over 90%. The strength retention rate data confirms that the ternary synergistic interface layer constructed in this invention has a strong bond and excellent hydrophobic shielding effect, effectively resisting the erosion of the interface by high humidity environments and ensuring the structural safety of the material throughout its entire life cycle.

[0057] Comparative Example 1, without the addition of graphene oxide, showed a decrease in specific modulus to 43.2 × 10⁻⁶. 6 The interlaminar shear strength dropped to 55.4 MPa due to the absence of graphene oxide, a key component. This resulted in the sulfonated polyether ether ketone resin being connected to the microspheres only by point-to-point ionic bonds, failing to form a surface-to-surface stress transfer network. Consequently, the microspheres became isolated defect points when subjected to stress.

[0058] In contrast, Comparative Example 2, which added excessive graphene oxide, experienced a further decrease in interlayer shear strength to 48.6 MPa and a reduction in wet heat aging retention rate to 73.7%. This may be because the excessive graphene oxide underwent severe stacking and aggregation within the narrow space of the interface layer. These aggregates not only became stress concentration sources but also formed capillary channels for moisture penetration. This indicates that controlling the amount of graphene oxide within the specific range of 0.2-0.5 parts in the technical solution of this application is key to achieving the best synergistic enhancement effect.

[0059] Comparative Example 3 used solid nano-silica of equal mass instead of hollow microspheres. Due to the high density of solid particles (approximately 2.2 g / cm³), the density of the solid particles was significantly reduced. 3 This resulted in a final specific modulus of only 40.1 × 10⁻⁶. 6 m² / s², which is nearly 25% lower than that of Example 3 of the present invention; This huge data gap irrefutably proves that the modification route using solid nanofillers in the existing technology cannot solve the lightweight requirements of ultra-long blades at all. Only the synergistic technical solution of the present invention is the only solution to improve the specific modulus.

[0060] Comparative Example 4 used the conventional aliphatic coupling agent KH550 instead of the N-phenyl-3-aminopropyltrimethoxysilane of the present invention. The results showed that although the initial strength was acceptable, the strength retention rate after wet heat aging was only 54.0%, showing a precipitous drop. This indicates the fragility of the hydrophilic aliphatic chain of KH550 under high-temperature hydrolysis environment. In contrast, the present invention utilizes the large-volume steric hindrance effect and hydrophobic properties of the benzene ring in phenylaminosilane to construct a dense shield on the surface of hydrophilic hollow glass microspheres, effectively blocking water erosion and thus achieving an unexpected aging resistance effect. Comparative Example 5 did not involve coupling treatment of the hollow glass microspheres; it only involved physical mixing. Its interlaminar shear strength was only 28.5 MPa, essentially losing its load-bearing capacity. This demonstrates that physical fillers without chemical bonds will instantly debond and fail under shear force.

[0061] Comparative Example 6 replaced the matrix with ordinary PEEK resin. Due to the lack of sulfonic acid groups, it could not form acid-base ionic bonds with the amino groups on the surface of the hollow glass microspheres, and its interlaminar shear strength was much lower than that of the technical solution of this application. This proves that the sulfonated polyether ether ketone matrix of the present invention is not arbitrarily selected, but rather a creative choice.

[0062] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. 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 basalt fiber reinforced material for wind turbine blades, characterized in that, By weight, it comprises the following: Basalt fiber 90-94 parts, sulfonated polyether ether ketone 4-8 parts, modified hollow glass microspheres 3-5 parts, graphene oxide 0.2-0.5 parts.

2. The basalt fiber reinforced material for wind turbine blades according to claim 1, characterized in that, The composition by weight is as follows: 92 parts basalt fiber, 6 parts sulfonated polyether ether ketone, 4 parts modified hollow glass microspheres, and 0.4 parts graphene oxide.

3. The basalt fiber reinforced material for wind turbine blades according to claim 1, characterized in that, The basalt fiber is a continuous basalt fiber roving of drawing grade, with a single filament diameter of 13±1μm and a density of 2.65g / cm³. 3 .

4. The basalt fiber reinforced material for wind turbine blades according to claim 1, characterized in that, The graphene oxide is a single-layer graphene oxide with a sheet diameter of 0.5~5μm.

5. A basalt fiber reinforced material for wind turbine blades according to any one of claims 1-4, characterized in that, The sulfonated polyether ether ketone was prepared by the following method: Polyether ether ketone powder was dried in a vacuum oven at 120°C for 6 hours; then, concentrated sulfuric acid (98% concentration) was added to a three-necked flask; under stirring, the dried polyether ether ketone powder was slowly added to the concentrated sulfuric acid in batches. After the powder was completely dissolved, the reaction system was heated to 50°C and stirred at a constant temperature for 5 hours; after the reaction was completed, the reaction solution was slowly poured into an ice-water mixture, and a white strip-shaped precipitate was precipitated; the precipitate was collected by filtration and repeatedly washed with deionized water until the pH of the filtrate was neutral; finally, the washed product was dried in a vacuum oven at 80°C for 24 hours to obtain sulfonated polyether ether ketone solid powder.

6. A basalt fiber reinforced material for wind turbine blades according to any one of claims 1-4, characterized in that, The modified hollow glass microspheres were prepared by the following method: Hollow glass microspheres were dispersed in a mixed solvent of ethanol and water; then glacial acetic acid was added to adjust the pH of the solution to 4.5-5.5, and the mixture was stirred for 15 minutes for surface activation; then, under stirring, a total of 3g of aminosilane coupling agent was slowly added dropwise to the suspension. After the addition was complete, the system was heated to 75°C and the reaction was carried out under mechanical stirring and reflux for 6 hours; after the reaction was completed, the solid product was collected by centrifugation and washed three times with anhydrous ethanol; finally, the washed product was placed in a 110°C forced-air drying oven for 2 hours to cure and dry, thus obtaining the modified hollow glass microspheres.

7. A basalt fiber reinforced material for wind turbine blades according to claim 6, characterized in that, The aminosilane coupling agent is N-phenyl-3-aminopropyltrimethoxysilane, CAS number: 3068-76-6.

8. A basalt fiber reinforced material for wind turbine blades according to claim 6, characterized in that, The hollow glass microspheres are high-strength borosilicate microspheres with an average particle size of 5-15 μm, a true density of 0.60 g / cm³, and a compressive strength of >60 MPa.

9. A method for preparing a basalt fiber reinforced material for wind turbine blades according to any one of claims 1-8, characterized in that, The preparation method includes the following steps: Step A: Preparation of synergistic sizing agent: Weigh sulfonated polyether ether ketone powder, dissolve it in N,N-dimethylformamide to prepare a matrix solution; add graphene oxide to the matrix solution and ultrasonically disperse for 30 minutes; add modified hollow glass microspheres to the dispersion and mechanically stir at a high shear rate for 60 minutes to form a uniform and stable sizing agent suspension; Step B: Fiber Impregnation and Forming: Basalt fibers are introduced into a continuous impregnation production line; the traction speed is controlled at 1.5 m / min, allowing the basalt fibers to pass through an impregnation tank containing the sizing agent suspension prepared in Step A, and the amount of sizing is controlled by the extrusion roller to ensure that the dispersion fully wets the interior of the fiber bundle; the impregnated fibers are then subjected to gradient drying and curing in three temperature-controlled zones: first, a pre-drying zone is used to remove most of the solvent from the surface; then, a vacuum drying zone is used to remove residual solvent from the micropores; finally, the fibers are treated in a heat-setting zone for 5 minutes, and after cooling and winding, a basalt fiber reinforcement material for wind turbine blades is obtained.

10. The method for preparing basalt fiber reinforced material for wind turbine blades according to claim 9, wherein the temperatures of the three temperature control zones are: 85°C in the pre-drying zone, 120°C in the vacuum drying zone, and 155°C in the heat setting zone.

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