High polymer / nanofiber composite material with high mechanical property and high weather resistance as well as preparation method and application of high polymer / nanofiber composite material

Abstract

The invention discloses a high polymer / nanofiber composite material with high mechanical property and high weather resistance as well as a preparation method and application thereof, and belongs to the technical field of polymer / nanofiber composite materials. According to the invention, polyether polyol participates in a prepolymerization reaction and is used for preparing a high-molecular polymer from modified nanofibers, and in the reaction process of a curing agent and isocyanate, the modified nanofibers and organic silicon are used as reinforcing phases to be added into the high-molecular polymer; the mechanical property, the weather resistance, the hydrophobic ice resistance, the chemical corrosion resistance and the wear resistance of the high-molecular polymer material are improved. The high polymer / nanofiber composite material with high mechanical property and high weather resistance provided by the invention is suitable for rain erosion protection of wind power blades. The preparation process is simple and efficient, the tensile strength, the elongation at break and the impact strength of the prepared high polymer / nanofiber composite material are remarkably enhanced, and the high polymer / nanofiber composite material is environment-friendly.

Description

Technical Field

[0001] This invention belongs to the field of polymer / nanofiber composite materials technology, specifically relating to high mechanical properties and high weather resistance polymer / nanofiber composite materials, their preparation methods and applications. Background Technology

[0002] Wind energy boasts advantages such as cleanliness, safety, recyclability, and large reserves. As a primary clean energy source for adjusting the energy structure, it is one of the world's fastest-growing energy sources and one of the most maturely developed in the field of new energy. Wind turbine generators are often installed in areas rich in wind resources. These areas have complex environmental conditions, and are affected by rainwater, dust, and saline vapor. The edges of wind turbine blades suffer severe corrosion, significantly reducing their lifespan. As the core energy conversion component of wind power generation, the structural strength and stability of the wind turbine blades directly affect the overall efficiency of wind power generation.

[0003] Polymers are large molecular compounds composed of numerous repeating structural units linked by chemical bonds. They possess advantages such as easy processing and molding, good hardness and strength, heat resistance, solvent resistance, and insulation. Depending on the monomers used in polymerization, they are classified into polyethylene, polyvinyl chloride, synthetic rubber, phenolic resin, polyurethane, polyurea, etc. Among these, polyurea materials are widely used in wind turbine blade protection due to their rapid reaction, ease of construction, high adhesion, and excellent impact resistance, addressing applications requiring corrosion resistance, wear resistance, and impact resistance. However, the microphase separation structure of polyurea results in weak mechanical properties, affecting its protective performance and significantly limiting the application of polyurea elastomers. Therefore, the development and preparation of high-strength, high-weather-resistant, and high-anti-icing polyurea composite materials are particularly important.

[0004] Currently, researchers mostly focus on enhancing the properties of polyurea elastomers by incorporating nanofillers, endowing them with multifunctional properties such as electrical conductivity, thermal conductivity, and flame retardancy. In recent years, nanofiber-reinforced polyurea elastomers have also attracted considerable attention, with poly(p-phenylenebenzodioxazole) fiber (PBO fiber) reinforcement being particularly prominent. The uniform dispersion and outstanding mechanical strength of PBO fibers improve the tensile strength and hardness of polyurea / nanofiber composites. Although research on PBO fiber-reinforced polyurea elastomers has shown encouraging results, significant shortcomings remain in terms of functional properties while developing these materials to maintain high strength and toughness.

[0005] Therefore, how to ensure the high strength and toughness of polymer / nanofiber composites while maintaining their functional properties has become an important issue that urgently needs to be addressed. Summary of the Invention

[0006] Therefore, the purpose of this invention is to provide a polymer / nanofiber composite material with high mechanical properties and high weather resistance, its preparation method and application. Polyether polyols participate in the prepolymerization reaction and are used to modify nanofibers to prepare polymers. In the reaction process of curing agent and isocyanate, modified nanofibers and organosilicon are added to the polymer as reinforcing phases. This improves the mechanical properties, weather resistance, hydrophobic and anti-icing properties, chemical corrosion resistance and wear resistance of the polymer material.

[0007] To achieve the above objectives, the present invention provides the following technical solution: In a first aspect, the present invention provides a method for preparing polymer / nanofiber composite materials with high mechanical properties and high weather resistance, comprising the following steps: S1, using organic solvents to clean nanofibers; S2, The nanofibers are placed in a mixed acid solution and ball-milled to obtain a nanofiber acid solution; S3, the nanofiber acid solution is pretreated by coagulation with an organic solvent, and after coagulation, it is washed with an organic solvent to obtain nanofiber gel. S4, the nanofiber gel and organic solvent are mixed and subjected to cell wall disruption treatment. After removing the organic solvent, the nanofibers are dispersed in polyether polyol and ball-milled to obtain a polyether polyol modified nanofiber solution. S5, the polyether polyol modified nanofiber solution is stirred and prepolymerized with isocyanate to obtain a prepolymer; S6, Under stirring, a mixture of organosilicon and curing agent is added to the prepolymer to obtain a composite material solution; S7. The composite material solution is cured and maintained to obtain the high mechanical properties and high weather resistance polymer / nanofiber composite material.

[0008] The coagulation pretreatment specifically involves spraying an acid solution of nanofibers with an organic solvent.

[0009] The nanofiber gel is golden yellow.

[0010] The polymers include one or more of polyurea and thermoplastic polyurethane elastomers.

[0011] The preferred polymer is polyurea.

[0012] The cell wall breaking process is carried out in a homogenizer.

[0013] In this process, the composite material solution is poured into a glass petri dish, and then the glass petri dish is transferred to a vacuum oven for curing.

[0014] The stirring prepolymerization is carried out under oil bath conditions, with an oil bath temperature of 70-90℃ and an oil bath time of the same as the stirring time.

[0015] Based on the above technical solution, the cleaning in S1 specifically includes: cleaning, filtering and drying using the organic solvent; the cleaning is ultrasonic cleaning, the cleaning is performed more than 4 times, and the cleaning time is more than 30 minutes each time.

[0016] Based on the above technical solution, further, the mixed acid solution in S2 is a mixed acid solution of methanesulfonic acid and trifluoroacetic acid, and the mass ratio of the nanofiber, the methanesulfonic acid and the trifluoroacetic acid is 0.02:1:1; the ball milling in S2 and S4 uses a steel jar, the balls are zirconium oxide grinding beads, tungsten carbide grinding beads or stainless steel grinding beads, the ball mill is a planetary ball mill, the grinding bead diameter is 3-5mm, the material-to-ball ratio is 1:1-1.1, the ball milling speed is 450-550rpm, and the ball milling time is more than 30min.

[0017] The nanofiber acid solution is brownish-yellow and viscous.

[0018] Among them, methanesulfonic acid is abbreviated as MSA; trifluoroacetic acid is abbreviated as TFA.

[0019] The mass ratio of nanofibers, methanesulfonic acid, and trifluoroacetic acid is 0.02:1:1.

[0020] Based on the above technical solution, further, the washing frequency in S3 is more than 3 times.

[0021] Based on the above technical solution, further, the cell wall breaking treatment time in S4 is more than 20 minutes; the removal of the organic solvent in S4 specifically involves: placing the cell wall broken solution in a vacuum filtration device, adding polyether polyol, repeatedly dissolving and filtering more than twice to remove the organic solvent.

[0022] Here, removing the organic solvent refers to removing excess organic solvent.

[0023] Based on the above technical solution, further, in S5 the prepolymerization temperature is 70-90℃ and the prepolymerization time is more than 2 hours; in S5 and S6 the stirring is magnetic stirring, the stirring speed is 125-175 rpm, the stirring and prepolymerization are carried out simultaneously, and the time is more than 2 hours; in S7 the curing temperature is 60-90℃ and the curing time is more than 5 days.

[0024] Based on the above technical solution, the mass ratio of the nanofiber, the isocyanate, the curing agent, the polyether polyol and the organosilicon is further 0.4-0.5:15-20:8-12:10-15:2-4.

[0025] Based on the above technical solution, the isocyanate is further selected from one or more of isophorone diisocyanate, toluene diisocyanate, dicyclohexylmethane diisocyanate, hexamethylene diisocyanate, and lysine diisocyanate. The curing agent is selected from polyaspartic acid ester, isophorone diamine, diethyltoluene diamine, dimethyl thiotoluene diamine, N,N' One or more of dialkylmethyldiamine and N,N'-dialkylphenyldiamine; The polyether polyol is selected from one or more of castor oil, diamino-terminated polyoxypropylene ether, and ternary amino-terminated polyoxypropylene ether. The organosilicon is selected from one or more of polydimethylsiloxane, silane coupling agent, and aminoalkyl organosilicon; The organic solvent is selected from N,N Dimethylformamide, N,N One or more of dimethylacetamide, acetone, anhydrous ethanol, and toluene; The nanofibers are selected from one or more of poly(p-phenylenebenzodioxazole) fiber, aramid fiber, and lignin.

[0026] The preferred isocyanate is dicyclohexylmethane diisocyanate.

[0027] Among them, isophorone diisocyanate is abbreviated as IPDI, toluene diisocyanate is abbreviated as TDI, dicyclohexylmethane diisocyanate is abbreviated as HMDI, hexamethylene diisocyanate is abbreviated as HDI, and lysine diisocyanate is abbreviated as LDI.

[0028] The curing agent is preferably polyaspartic acid ester.

[0029] Among them, polyaspartic acid ester is abbreviated as F420, isophorone diamine is abbreviated as IPDA, diethyltoluene diamine is abbreviated as DETDA, and dimethylthiotoluene diamine is abbreviated as DMTDA.

[0030] Among them, castor oil is preferred as the polyether polyol.

[0031] The organosilicon is preferably polydimethylsiloxane.

[0032] Polydimethylsiloxane is abbreviated as PDMS.

[0033] Among them, the organic solvent is preferably N,N Dimethylformamide, anhydrous ethanol, or acetone. Acetone is the organic solvent in S1. Anhydrous ethanol is the organic solvent in S3 and S4. Where N,N Dimethylformamide, abbreviated as DMF.

[0034] Among them, the nanofibers are preferably poly(p-phenylenebenzodioxazole) fibers.

[0035] Among them, poly(p-phenylenebenzodioxazole) fiber is abbreviated as PBO fiber.

[0036] Secondly, the present invention provides a polymer / nanofiber composite material with high mechanical properties and high weather resistance prepared by the above method, having a tensile strength of 42.57-47.63 MPa, an elongation at break of 1023.54-1167.61%, a hydrophobic contact angle of 128.64±5.6°, and a mass loss rate of 0.87-1.48%.

[0037] Thirdly, the present invention provides the application of the above-mentioned high mechanical properties and high weather resistance polymer / nanofiber composite material in the rain erosion protection of wind turbine blades.

[0038] Compared with the prior art, the present invention has the following beneficial effects: 1. In this invention, polyether polyols participate in the prepolymerization reaction and are used to modify nanofibers to prepare polymers. During the reaction between the curing agent and isocyanate, modified nanofibers and organosilicon are added to the polymer as reinforcing phases, thereby improving the mechanical properties, weather resistance, hydrophobic and anti-icing properties, chemical corrosion resistance, and wear resistance of the polymer material.

[0039] 2. The high mechanical properties and high weather resistance polymer / nanofiber composite material provided by this invention are suitable for rain erosion protection of wind turbine blades.

[0040] 3. The preparation process of this invention is simple and efficient, and the tensile strength, elongation at break and impact strength of the prepared polymer / nanofiber composite material are significantly enhanced, and it is environmentally friendly. Attached Figure Description

[0041] To more clearly illustrate the embodiments of the present invention, the accompanying drawings involved in the embodiments will be briefly described below.

[0042] Figure 1 This is an overall flow chart of the preparation method of the high mechanical properties and high weather resistance polymer / nanofiber composite material of the present invention; Figure 2 The preparation process of PBO nanofiber gel in Example 1 of the present invention; Figure 3 The preparation process of the modified PBO nanofibers in Example 1 of this invention; Figure 4 The preparation process of the bio-based polyurea / PBO nanofiber composite material in Example 1 of this invention is described. Detailed Implementation

[0043] The present invention will be described in detail below with reference to the embodiments. However, the implementation of the present invention is not limited thereto. Obviously, the embodiments described below are only some embodiments of the present invention. For those skilled in the art, other similar embodiments can be obtained without creative effort and all fall within the protection scope of the present invention.

[0044] Unless otherwise specified, all raw materials and reagents mentioned below are commercially available products, and all process steps or methods not mentioned in detail are process steps or methods known to those skilled in the art.

[0045] The sources of some raw materials and reagents used in the following examples and comparative examples are as follows: 99% pure dicyclohexylmethane diisocyanate (HMDI) was purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.; PBO fiber was purchased from DuPont through Chengdu Xincheng New Material Technology Co., Ltd.; polyether polyol castor oil was purchased from Shanghai Maclean Biochemical Technology Co., Ltd.; F420 was purchased from Shenzhen Feiyang Junyan New Material Co., Ltd. PDMS consists of component A (silicone elastomer prepolymer) and component B (curing agent), mixed in a 10:1 ratio according to the usage standard and purchased from Dow Corning. Unless otherwise specified, all raw materials and reagents were used directly without further purification.

[0046] In the following examples and comparative examples, the tensile strength of the examples and comparative examples was tested in accordance with ISO 37:2017.

[0047] In the following examples and comparative examples, the impact strength of the examples and comparative examples was tested according to ISO 179-2:2020 standard, with aluminum sheets as the substrate.

[0048] In the following examples and comparative examples, the corrosion resistance test procedures were as follows: The samples from Example 1 and Comparative Examples 1-2 were placed in acidic solution (5% H2SO4), alkaline solution (5% NaOH), and deionized water for 10 days. The samples were weighed daily to assess their chemical resistance.

[0049] In the following examples and comparative examples, the hydrophobicity test steps are as follows: the samples in Example 1 and Comparative Examples 1-2 were analyzed using diiodomethane as a solvent to measure the contact angle of the coating surface in order to evaluate its hydrophobic properties.

[0050] In the following examples and comparative examples, the wear resistance test steps are as follows: The samples in examples and comparative examples 1-2 were subjected to 1000 wear cycles in a Taber wear tester, and the wear resistance performance was evaluated by the mass loss rate.

[0051] Example 1 This embodiment prepares a polymer / nanofiber composite material with high mechanical properties and high weather resistance. The specific process is as follows.

[0052] 1. First, PBO fibers were ultrasonically cleaned in 100 ml of acetone solution, and this cleaning was repeated 5 times. Then, 0.4 g of cleaned PBO fibers were added to a mixture of 20 g MSA and 20 g TFA. The mixture was poured into a ball mill jar containing 4 mm zirconia balls and ball-milled at 500 rpm for 1 hour. After ball milling, a brownish-yellow viscous PBO acid solution was obtained. Using a casting method, 10 g of PBO / acid solution was spread on the bottom of a 52 mm diameter petri dish and placed in a fume hood for 5 minutes to allow the acid fumes to dissipate. Then, 10 ml of anhydrous ethanol was sprayed for coagulation treatment. After solidification, the solution was washed repeatedly with anhydrous ethanol 5 times to remove excess acid, forming a golden-yellow PBO nanofiber gel.

[0053] 2. Castor oil modification of PBO nanofibers was performed using a mechanochemical method, namely high-speed microball milling. In the gel state, the PBO nanofiber gel was added to a homogenizer using anhydrous ethanol as solvent and treated for 30 minutes to open the re-crosslinked PBO nanonetwork. Then, the solvent was repeatedly exchanged three times between the PBO-ethanol solution and castor oil using a vacuum filtration device to remove excess ethanol. Finally, PBO was dispersed again in 40 g of castor oil using ball milling to obtain a uniformly dispersed PBO-CO solution.

[0054] 3. Prepare 3.135g of PDMS solution (maintaining a resin to curing agent mass ratio of 10:1) and add 14.18g of F420 solution. Stir for 1 hour at a stirring speed of 150rpm.

[0055] 4. Mix 18.55g of PBO-CO solution with 10g of HMDI in an oil bath using magnetic stirring at a speed of 150rpm. Gradually increase the oil bath temperature from room temperature to 85℃ and maintain this temperature for 3 hours to form a prepolymer. Then, while manually stirring the solution with a glass rod, slowly add 17.315g of a mixed solution of F420 and PDMS, stirring for 5 minutes. Pour the resulting solution into a glass petri dish mold and transfer it to a vacuum oven at 75℃. After high-temperature curing for 7 days, the final elastomer sample is obtained.

[0056] In this embodiment, the amount of PBO nanofibers added is 0.1 wt% of the total mass of the polymer / nanofiber composite material.

[0057] Example 2 This embodiment prepares a polymer / nanofiber composite material with high mechanical properties and high weather resistance.

[0058] The difference between this embodiment and Example 1 is that the amount of PBO nanofibers added is 0.025 wt% of the total mass of the polymer / nanofiber composite material, while the amounts of other reagents and the operation are exactly the same.

[0059] Example 3 This embodiment prepares a polymer / nanofiber composite material with high mechanical properties and high weather resistance.

[0060] The difference between this embodiment and Example 1 is that the amount of PBO nanofibers added is 0.05 wt% of the total mass of the polymer / nanofiber composite material, while the amounts of other reagents and the operation are exactly the same.

[0061] Example 4 This embodiment prepares a polymer / nanofiber composite material with high mechanical properties and high weather resistance.

[0062] The difference between this embodiment and Example 1 is that the amount of PBO nanofibers added is 0.15 wt% of the total mass of the polymer / nanofiber composite material, while the amounts of other reagents and the operation are exactly the same.

[0063] Example 5 This embodiment prepares a polymer / nanofiber composite material with high mechanical properties and high weather resistance.

[0064] The difference between this embodiment and Example 1 is that the amount of PBO nanofibers added is 0.2 wt% of the total mass of the polymer / nanofiber composite material, while the amounts of other reagents and the operation are exactly the same.

[0065] Example 6 The differences between this embodiment and Embodiment 1 are as follows.

[0066] The mass ratio of nanofibers, isocyanate, curing agent, polyether polyol and organosilicon is 0.4:15:8:10:2.

[0067] Example 7 The differences between this embodiment and Embodiment 1 are as follows.

[0068] The mass ratio of nanofibers, isocyanate, curing agent, polyether polyol and organosilicon is 0.5:20:12:15:4.

[0069] Comparative Example 1 This comparative example prepares a polyurea elastomer, and the specific process is as follows.

[0070] After mixing castor oil, HMDI and F420 in a certain proportion and curing, polyurea elastomer samples can be prepared.

[0071] Comparative Example 2 This comparative example prepares a bio-based polyurea elastomer modified with organosilicon.

[0072] The difference between this comparative example and Example 1 is that the organosilicon solution was not mixed with the PBO-F420 solution, but rather with a certain amount of F420 solution.

[0073] The test data of the materials prepared in Examples 1 to 5 and Comparative Examples 1 to 2 are as follows.

[0074] Table 1 shows the mechanical property test data of Examples 1 to 5 and Comparative Examples 1 to 2.

[0075]

[0076] Table 1 shows that the type and content of the reinforcing filler both affect the mechanical properties of the polymer / nanofiber composite. With only organosilicon PDMS added, both tensile strength and elongation at break are significantly improved compared to the matrix without reinforcing phase. With the addition of both organosilicon and nanofibers, the tensile strength and elongation at break are significantly improved compared to the matrix without reinforcing phase or with only organosilicon PDMS, depending on the nanofiber content. This is mainly attributed to the interpenetrating network (IPN) structure formed between the polyurea matrix, organosilicon PDMS, and PBO nanofibers. The best mechanical properties were observed when the PBO nanofiber content was 0.1 wt%.

[0077] Table 2 shows the impact resistance test data for Examples 1 to 5 and Comparative Examples 1 to 2.

[0078]

[0079] Table 2 shows that both the type and content of the reinforcing filler affect the impact resistance of the polymer / nanofiber composite. With only organosilicon PDMS added, the impact resistance is significantly improved compared to the matrix without reinforcing phase. With the addition of both organosilicon and nanofibers, the impact resistance is significantly improved compared to the matrix without reinforcing phase or with only organosilicon PDMS, depending on the nanofiber content. This is mainly attributed to the interpenetrating network (IPN) structure formed between the polyurea matrix, organosilicon PDMS, and PBO nanofibers. The best impact resistance is observed when the PBO nanofiber content is 0.1 wt%.

[0080] Table 3 shows the corrosion resistance data for Example 1 and Comparative Examples 1 to 2.

[0081]

[0082] Table 3 shows that the type and content of the reinforcing filler both affect the corrosion resistance of the polymer / nanofiber composite material. With only organosilicon PDMS added, the corrosion resistance is significantly improved compared to the matrix without reinforcing phase. With the addition of both organosilicon and nanofibers, the corrosion resistance is significantly improved compared to the matrix without reinforcing phase or with only organosilicon PDMS, depending on the nanofiber content. The best corrosion resistance is achieved when the PBO nanofiber content is 0.1 wt%.

[0083] Table 4 shows the hydrophobic performance data for Example 1 and Comparative Examples 1 to 2.

[0084]

[0085] Table 4 shows that the type of reinforcing filler affects the hydrophobic properties of the polymer / nanofiber composite. The matrix without the addition of organosilicon PDMS and PBO nanofibers is not hydrophobic, while the introduction of organosilicon PDMS alone increases the hydrophobic angle, indicating hydrophobicity. Further addition of PBO nanofibers to form an IPN structure results in a hydrophobic angle greater than 125°, further enhancing the hydrophobicity.

[0086] Table 5 shows the wear resistance data for Example 1 and Comparative Examples 1 to 2.

[0087] Table 5 shows that the type of reinforcing filler affects the wear resistance of polymer / nanofiber composites. The matrix without silicone PDMS and PBO nanofibers exhibits poor wear resistance, while the wear rate decreases when silicone PDMS is introduced alone. Furthermore, the addition of PBO nanofibers to form an IPN structure results in the lowest wear rate.

[0088] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing a high mechanical performance and high weatherability polymer / nanofiber composite material, characterized by, It comprises the following steps: S1, cleaning nanofibers with organic solvent; S2, placing the nanofibers in a mixed acid solution for ball milling to obtain a nanofiber acid solution; S3, coagulating the nanofiber acid solution with organic solvent, washing with organic solvent after coagulation to obtain a nanofiber gel; S4, mixing the nanofiber gel with organic solvent for wall breaking treatment, removing the organic solvent, and dispersing the nanofibers in polyether polyol for ball milling to obtain a polyether polyol modified nanofiber solution; S5, stirring the polyether polyol modified nanofiber solution with isocyanate for prepolymerization to obtain a prepolymer; S6, adding a mixed solution of silicone and curing agent to the prepolymer under stirring to obtain a composite material solution; S7, curing and maintaining the composite material solution to obtain the high mechanical performance and high weather resistance polymer / nanofiber composite material.

2. The method for preparing high-mechanical-performance and high-weather-resistance polymer / nanofiber composite materials according to claim 1, characterized in that, The cleaning in S1 is specifically washing, filtering and drying with the organic solvent; the washing is ultrasonic washing, the washing is more than 4 times, and the washing time is more than 30 minutes each time.

3. The method for preparing high-mechanical-performance and high-weather-resistance polymer / nanofiber composite materials according to claim 1, characterized in that, The mixed acid solution in S2 is a mixed acid solution of methanesulfonic acid and trifluoroacetic acid, and the mass ratio of the nanofibers, the methanesulfonic acid and the trifluoroacetic acid is 0.02:1:1; the ball milling in S2 and S4 uses a steel tank, the balls are zirconia grinding beads, tungsten carbide grinding beads or stainless steel grinding beads, the ball mill is a planetary ball mill, the grinding bead diameter is 3-5 mm, the material to ball ratio is 1:1-1.1, the ball milling speed is 450-550 rpm, and the ball milling time is more than 30 minutes.

4. The method of claim 1, wherein the high mechanical performance and high weatherability polymer / nanofiber composite is prepared by the steps of: The washing in S3 is more than 3 times.

5. The method for preparing high-mechanical-performance and high-weather-resistance polymer / nanofiber composite materials according to claim 1, characterized in that, The wall breaking treatment time in S4 is more than 20 minutes; the removal of the organic solvent in S4 is specifically placing the solution after wall breaking in a vacuum filtration device, adding polyether polyol, repeatedly dissolving and filtering more than 2 times, and removing the organic solvent.

6. The method of claim 1, wherein the high mechanical performance and high weatherable polymer / nanofiber composite is prepared by the steps of: The prepolymerization temperature in S5 is 70-90℃, and the prepolymerization time is more than 2 hours; the stirring in S5 and S6 is magnetic stirring, the stirring speed is 125-175 rpm, the stirring is carried out simultaneously with the prepolymerization, and the time is more than 2 hours; the curing temperature in S7 is 60-90℃, and the curing time is more than 5 days.

7. The method of claim 1, wherein the high mechanical performance and high weatherability polymer / nanofiber composite is prepared by the steps of: The mass ratio of the nanofibers, the isocyanate, the curing agent, the polyether polyol and the silicone is 0.4-0.5:15-20:8-12:10-15:2-4.

8. The method for preparing high-mechanical-performance and high-weather-resistance polymer / nanofiber composite materials according to claim 1, characterized in that, The isocyanate is selected from one or more of isophorone diisocyanate, toluene diisocyanate, dicyclohexylmethane diisocyanate, hexamethylene diisocyanate and lysine diisocyanate; The curing agent is selected from one or more of polyaspartic ester, isophorone diamine, diethyl toluene diamine, dimethylthio toluene diamine, N,N' dialkyl methyl diamine, N,N' dialkyl phenyl diamine. The polyether polyol is selected from one or more of castor oil, dibasic amino-terminated polyoxypropylene ether and tribasic amino-terminated polyoxypropylene ether; The silicone is selected from one or more of polydimethylsiloxane, silane coupling agent and aminoalkyl silicone; The organic solvent is selected from one or more of N,N-dimethylformamide, N,N-dimethylacetamide, acetone, anhydrous ethanol, and toluene. The organic solvent is selected from one or more of N,N-dimethylformamide, N,N-dimethylacetamide, acetone, anhydrous ethanol, and toluene. The organic solvent is selected from one or more of N,N-dimethylformamide, N,N-dimethylacetamide, acetone, anhydrous ethanol, and toluene. The nanofibers are selected from one or more of poly-p-phenylene benzobisoxazole fibers, aramid fibers and lignin.

9. The high mechanical performance and high weatherable polymer / nanofiber composite prepared according to the method of any one of claims 1 to 8, wherein, The tensile strength is 42.57-47.63 MPa, the elongation at break is 1023.54-1167.61%, the hydrophobic contact angle is 128.64±5.6°, and the mass loss rate is 0.87-1.48%.

10. Use of the high mechanical performance and high weatherability polymer / nanofiber composite material according to claim 9 for the rain erosion protection of wind turbine blades.

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