A method for preparing a reinforced and toughened bamboo fiber unmanned aerial wing

Abstract

The application discloses a kind of preparation methods of reinforcing toughening bamboo fiber unmanned aerial wing, comprising: S1, cutting bamboo fiber and carbon fiber, add to fiber mixing machine and uniformly mix;S2, surface treatment is carried out to mixed bamboo fiber and carbon fiber with silane coupling agent;S3, bamboo fiber and carbon fiber after surface treatment are mixed with resin, and form bamboo fiber composite material;S4, mixed composite material is injected into the mold of unmanned aerial wing, and carries out mould pressing forming and heat solidification treatment;S5, to the unmanned aerial wing of demoulding is polished and is handled, carries out multilayer coating spraying and solidification treatment;The bamboo fiber of the application provides lightweight and toughness as main component, the strength and durability of composite material are improved as reinforcing phase by carbon fiber, the interface bonding force between fiber and resin is enhanced by the use of silane coupling agent, and the corrosion resistance and wear resistance of unmanned aerial wing are further improved by multilayer coating spraying.

Description

Technical Field

[0001] This invention relates to the field of bamboo fiberboard technology, and more particularly to a method for preparing reinforced and toughened bamboo fiber drone wings. Background Technology

[0002] Agricultural drones are unmanned aerial vehicles specifically designed for agricultural applications, playing a crucial role in agricultural operations and farmland information gathering. Agricultural operations include pesticide spraying and seed sowing, while farmland information gathering involves soil monitoring and crop growth monitoring. By incorporating plant protection spraying systems, agricultural drones can achieve automated, precise control, and small-batch spraying of pesticides. Compared to traditional pesticide spraying methods, drone spraying efficiency can be significantly increased by 8-10 times, while saving 30%-50% of pesticides and 90% of water. This not only improves operational efficiency but also helps reduce the potential harm of pesticides to the environment and human health.

[0003] Bamboo fiber, a natural cellulose fiber extracted from bamboo, exhibits unique advantages in the preparation of agricultural drone wings due to its light weight and straight, dense fiber structure. Drone wings made from bamboo fiber can achieve better weight reduction, thereby reducing the overall weight of the drone and improving flight efficiency. Bamboo fiber also has a certain strength and toughness, which can ensure that the wings are not easily broken or deformed when subjected to external forces.

[0004] However, when performing pesticide spraying operations, bamboo fiber drone wings need to possess strong load-bearing capacity to ensure that the wings can support the weight of the pesticide tank and remain stable during flight. Simultaneously, because pesticides are corrosive, bamboo fiber drone wings also need to have anti-corrosion properties to extend the wing's lifespan and protect the internal structure from corrosion. Therefore, it is necessary to improve the strength and corrosion resistance of bamboo fiber in the fabrication of drone wings to meet the requirements of pesticide spraying.

[0005] Therefore, it is necessary to improve the preparation of bamboo fiber drone wings in the existing technology to solve the above problems. Summary of the Invention

[0006] This invention overcomes the shortcomings of the prior art and provides a method for preparing reinforced and toughened bamboo fiber drone wings, aiming to solve the problems of improving the strength and corrosion resistance of drone wings prepared from bamboo fiber in the prior art.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is: a method for preparing reinforced and toughened bamboo fiber drone wings, comprising the following steps;

[0008] S1. Cut bamboo fiber and carbon fiber and add them to the fiber mixer for uniform mixing;

[0009] S2, surface treatment of the mixed bamboo fibers and carbon fibers with a silane coupling agent;

[0010] S3, mixing the surface treated bamboo fibers and carbon fibers with a resin to form a bamboo fiber composite material;

[0011] S4, injecting the mixed bamboo fiber composite material into a mold of a UAV wing for mold pressing and heat setting treatment;

[0012] S5, polishing the demolded UAV wing, multi-layer paint spraying and curing treatment.

[0013] In a preferred embodiment of the present application, in step S1, the mixing mass ratio of the bamboo fibers to the carbon fibers is 2.3-4:1; the length of the bamboo fibers is 10-25 mm, the diameter of the bamboo fibers is 20-30 μm; the length of the carbon fibers is 1-6 mm, the diameter of the carbon fibers is 5-10 μm; the rotating speed of the fiber mixer is 800-1000 r / min, and the mixing time is 20-30 min.

[0014] In a preferred embodiment of the present application, in step S2, the mixture of the bamboo fibers and the carbon fibers is mixed with a silane coupling agent solution with a concentration of 0.5%-1.5%, the mass ratio of the mixture to the silane coupling agent is 1:0.01-0.03, the water bath heating temperature is 50-70℃, the mixing time is 2-4 h, and the stirring speed is 300-500 r / min.

[0015] In a preferred embodiment of the present application, in step S3, the mass ratio of the mixture of the bamboo fibers and the carbon fibers to the resin is 1:1.2-1.5, the mixing temperature is 25-30℃, the stirring speed is 200-400 r / min, the mixing time is 15-30 min, and the resin is one or a mixture of more than one of epoxy resin, polyurethane resin and phenolic resin.

[0016] In a preferred embodiment of the present application, in step S4,

[0017] S41, the bamboo fiber composite material is injected into the mold at a rate of 50-100 g / min, and the vacuum degree is -0.9 to -0.95 mbar;

[0018] S42, the mold pressing temperature is 100-150℃, the mold pressing pressure is 8-10 MPa, and the mold pressing time is 1-2 h during the mold pressing treatment;

[0019] S43, multi-stage heat setting treatment is performed simultaneously with the mold pressing treatment;

[0020] S44, the heat set bamboo fiber composite material is cooled to 20℃ at a rate of 20℃ / h and subjected to demolding treatment.

[0021] In a preferred embodiment of the present application, in step S43, the multi-stage heat curing treatment comprises:

[0022] The heating temperature of the primary curing stage is 70-100 DEG C, and the heating time is 5-15 min;

[0023] The heating temperature of the intermediate curing stage is 100-130 DEG C, and the heating time is 0.5-1 h;

[0024] The heating temperature of the final curing stage is 130-150 DEG C, and the heating time is 1-4 h.

[0025] In a preferred embodiment of the present application, in step S5, the rough sandpaper with a mesh size of 80-120 is used for polishing for 15-20 min, and then the fine sandpaper with a mesh size of 240-400 is used for polishing for 20-30 min.

[0026] In a preferred embodiment of the present application, in step S5, the multi-layer coating is sprayed as follows:

[0027] The bottom layer is sprayed with an epoxy primer, the solid content of the epoxy primer is 40%-60%, the spraying pressure is 0.3-0.6 MPa, and after the spraying is completed, curing is performed at 60-80 DEG C, and the curing time is 1-2 h;

[0028] The intermediate layer is sprayed with polytetrafluoroethylene, the solid content of the polytetrafluoroethylene is 10%-15%, the spraying pressure is 0.4-0.7 MPa, and after the spraying is completed, curing is performed at 200-260 DEG C, and the curing time is 0.5-1 h;

[0029] The top layer is sprayed with a polytetrafluoroethylene and liquid crystal polymer blend, the solid content is 15-20%, the spraying pressure is 0.4-0.7 MPa, and after the spraying is completed, curing is performed at 150-200 DEG C, and the curing time is 15-60 min.

[0030] In a preferred embodiment of the present application, the preparation of the polytetrafluoroethylene and liquid crystal polymer blend comprises: mixing liquid crystal polymer, polytetrafluoroethylene, a compatibilizer and an antioxidant in a mass ratio of 2-4:1:0.2-0.8:0.02-0.05, the mixing temperature is 320-400 DEG C, the stirring speed is 200-600 r / min, and the stirring time is 20-40 min.

[0031] The present application solves the defects in the background art, and has the following beneficial effects:

[0032] (1) The present application provides a method for preparing a reinforced and toughened bamboo fiber unmanned aerial wing, bamboo fiber as the main component provides light weight and toughness, carbon fiber as the reinforcing phase improves the strength and durability of the composite material, the use of silane coupling agent enhances the interfacial bonding force between the fiber and the resin, and the spraying of multi-layer paint further improves the corrosion resistance and wear resistance of the unmanned aerial wing.

[0033] (2) The present application adopts multi-layer paint spraying technology, including epoxy primer, polytetrafluoroethylene intermediate layer and polytetrafluoroethylene and liquid crystal polymer blend topcoat, which improves the corrosion resistance and wear resistance of the unmanned aerial wing, the epoxy primer provides strong adhesion between the coating and the composite material, providing a good adhesion foundation for the subsequent coating, enhancing the overall strength and durability of the coating system, the polytetrafluoroethylene intermediate layer provides excellent corrosion resistance and wear resistance for the unmanned aerial wing, and at the same time, as an intermediate layer, it provides a solid support for the topcoat, the polytetrafluoroethylene and liquid crystal polymer blend topcoat forms a dense three-dimensional network structure inside the coating under high temperature, further improving the protective performance and mechanical strength of the coating, and prolonging the corrosion resistance of the unmanned aerial wing to pesticides.

[0034] (3) The present application adopts the mixing of bamboo fiber and carbon fiber, combined with the uniform mixing operation of the fiber mixing machine, effectively improving the strength and toughness of the unmanned aerial wing, the combination of bamboo fiber and carbon fiber fully utilizes the light weight and toughness of bamboo fiber and the high strength characteristics of carbon fiber, avoiding the high cost of using all carbon fiber, using carbon fiber as the reinforcing phase of bamboo fiber, through the uniform mixing of the fiber mixing machine, ensuring the uniform dispersion and mixing of the two fibers, reducing the damage to the physical properties of the fibers, so as to prepare a lightweight and high-strength unmanned aerial wing

[0035] (4) The present application adopts multi-stage heat treatment method during molding and heat treatment process, effectively controls the curing process of the composite material, the primary curing stage makes the resin preliminary crosslinking, the intermediate curing stage improves the crosslinking density and reduces the residual stress, and the final curing stage ensures the complete curing of the resin, the multi-stage heat treatment method can optimize the performance of bamboo fiber composite material, improve the strength, toughness and durability of the unmanned aerial wing.

[0036] (5) The present application treats the mixed bamboo fiber and carbon fiber with silane coupling agent, which enhances the interfacial bonding force between the fiber and the resin, the silane coupling agent has good fiber affinity and resin affinity, which can firmly bond the fiber and the resin together, avoiding the interface defects in the composite material, and improving the overall performance of the composite material. BRIEF DESCRIPTION OF DRAWINGS

[0037] In order to make the technical solutions in the embodiments of the present application or the prior art clearer, the accompanying drawings needed in the embodiments or prior art description will be briefly introduced. Obviously, the accompanying drawings in the following description only represent some embodiments of the present application, and all other drawings obtained by those of ordinary skill in the art without any creative effort belong to the protection scope of the present application.

[0038] Figure 1 is a flow chart of the preferred embodiment of the present application; DETAILED DESCRIPTION

[0039] The technical solutions in the embodiments of the present application will be described clearly and completely in combination with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments only represent some embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without any creative effort belong to the protection scope of the present application.

[0040] In the following description, many specific details are set forth in order to provide a thorough understanding of the present application. However, the present application can be practiced without the specific details, other than those described in the specification, and therefore the scope of the present application is not limited to the specific embodiments disclosed in the specification.

[0041] In the description of the present application, it should be noted that, unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connecting" should be understood in a broad sense, for example, can be fixed connection, can also be detachable connection, or integrally connected; can be mechanical connection, can also be electrical connection; can be directly connected, can also be indirectly connected through an intermediate medium, can be the communication inside two elements. For those of ordinary skill in the art, the specific meaning of the above terms in the present application can be understood through specific circumstances.

[0042] A preparation method of a reinforced and toughened bamboo fiber unmanned aerial vehicle wing, comprising the following steps:

[0043] S1, cutting bamboo fibers and carbon fibers, and adding them into a fiber mixing machine for uniform mixing;

[0044] S2, surface treating the mixed bamboo fibers and carbon fibers with a silane coupling agent;

[0045] S3, mixing the surface treated bamboo fibers and carbon fibers with resin to form a bamboo fiber composite material;

[0046] S4, injecting the mixed bamboo fiber composite material into a mold of the unmanned aerial vehicle wing for mold pressing and heat setting treatment;

[0047] S5, polishing the demolded unmanned aircraft wing, performing multi-layer paint spraying and curing treatment.

[0048] Specifically, in step S1, the mixing mass ratio of bamboo fiber and carbon fiber is 2.3-4:1; the length of the bamboo fiber is 10-25 mm, and the diameter of the bamboo fiber is 20-30 μm; the length of the carbon fiber is 1-6 mm, and the diameter of the carbon fiber is 5-10 μm; the rotating speed of the fiber mixing machine is 800-1000 r / min, and the mixing time is 20-30 min, so as to ensure uniform dispersion and mixing of the bamboo fiber and the carbon fiber and reduce damage to the physical properties of the fiber. In the composite material, the bamboo fiber is the main component, and the carbon fiber acts as a reinforcing phase, which helps to maintain the lightweight of the bamboo fiber composite material, and at the same time, the carbon fiber further improves the strength and durability of the bamboo fiber composite material.

[0049] The longer fiber length helps to form a stronger fiber network in the composite material, improving the strength and toughness of the material; the addition of chopped carbon fiber to the bamboo fiber composite material helps to maintain the integrity of the structure when subjected to impact load, prevent crack propagation and damage, through its high impact resistance; uniform distribution of the chopped carbon fiber helps to homogenize the stress and reduce stress concentration, thereby enhancing the durability of the material; thanks to the high strength and high modulus characteristics of the carbon fiber, the overall mechanical properties of the bamboo fiber composite material are significantly improved.

[0050] Specifically, in step S2, the mixture of bamboo fiber and carbon fiber is mixed with a silane coupling agent solution with a concentration of 0.5%-1.5%, the mass ratio of the mixture to the silane coupling agent is 1:0.01-0.03, the water bath heating temperature is 50-70℃, the mixing time is 2-4 h, and the stirring speed is 300-500 r / min;

[0051] The silane coupling agent is a kind of low molecular organic silicon compound with special structure. In the mixture of bamboo fiber and carbon fiber, the organic functional group of the silane coupling agent reacts with the functional group on the surface of the bamboo fiber and the carbon fiber to form a chemical bond, which helps to enhance the interaction between the fibers and improve the overall performance of the mixture of bamboo fiber and carbon fiber; the silane coupling agent improves the polarity of the fiber surface and forms a chemical bond, enhancing the interfacial bonding force between the fiber and the resin matrix, making it easier to mix and infiltrate with the resin matrix, thereby improving the bonding strength.

[0052] Specifically, in step S3, the mass ratio of the mixture of bamboo fiber and carbon fiber to resin is 1:1.2-1.5; the mixing temperature is 25-30℃, so as to ensure the fluidity of the resin and the uniformity of the mixture, and at the same time, avoid premature curing of the resin due to too high temperature; the stirring speed is 200-400 r / min; the mixing time is 15-30 min; and the resin is uniformly wrapped around the fiber to form a uniform composite material.

[0053] The resin is one or a mixture of epoxy resin, polyurethane resin and phenolic resin;

[0054] Through the mixing of resin and fiber, the high strength of bamboo fiber and carbon fiber and the adhesion of resin are combined, the resin uniformly wraps around the fiber, fills the voids of bamboo fiber and carbon fiber, and forms a uniform composite material, which helps to improve the mechanical properties and overall quality of the composite material.

[0055] Specifically, in step S4, the bamboo fiber composite material needs to be in a vacuum environment when it is injected into the mold at a rate of 50-100 g / min, with a vacuum degree of -0.9 to -0.95 mbar, to exclude air in the injected liquid and air in the mold, to prevent bubbles from existing in the composite material after molding. The mold pressing temperature is 100-150℃, the mold pressing pressure is 8-10MPa, and the mold pressing time is 1-2h; to ensure that the composite material is fully filled in the mold.

[0056] The heat treatment adopts a multi-stage heat treatment method:

[0057] The heating temperature in the primary curing stage is 70-100℃, and the heating time is 5-15min; so that the resin is preliminarily crosslinked to form a preliminary network structure;

[0058] The heating temperature in the intermediate curing stage is 100-130℃, and the heating time is 0.5-1h; to increase the crosslinking density and reduce the residual stress in the resin, and to enhance the cohesion of the material;

[0059] The heating temperature in the final curing stage is 130-150℃, and the heating time is 1-4h, to ensure that the resin is completely cured to form a highly crosslinked network structure, providing the final performance required by the composite material.

[0060] After heat curing, the bamboo fiber composite material is cooled to 20℃ at a rate of 20℃ / h to avoid thermal stress and material deformation that may be caused by rapid cooling, and is subjected to demolding treatment.

[0061] During the curing process, the molecular chains of the resin are connected to each other through chemical bonding or physical entanglement to form a three-dimensional network structure, which improves the mechanical strength and stability of the bamboo fiber composite material. If the curing is not complete, there may be uncured resin areas in the composite material, which will reduce the overall performance of the composite material.

[0062] Specifically, in step S5, the polishing treatment is polished with 80-120 mesh coarse sandpaper for 15-20min to remove burrs, unevenness and small defects on the surface of the unmanned aerial vehicle wing, and then polished with 240-400 mesh fine sandpaper for 20-30min to ensure the smoothness and flatness of the surface of the unmanned aerial vehicle wing, providing a good substrate for coating spraying.

[0063] Specifically, in step S5, the multi-layer coating is sprayed as follows:

[0064] The bottom layer is sprayed with an epoxy primer, the solid content of the epoxy primer is 40%-60%, the spraying pressure is 0.3-0.6 MPa, and after spraying, curing is carried out at 60-80°C, the curing time is 1-2h; the epoxy primer provides strong adhesion between the coating system and the bamboo fiber composite material, ensuring the durability and stability of the coating, the solid content of the epoxy primer is 40%-60%, which helps to form a thick bottom layer, providing a solid and stable foundation for the subsequent coating.

[0065] The middle layer is sprayed with polytetrafluoroethylene, the solid content of the polytetrafluoroethylene is 10%-15%, the spraying pressure is 0.4-0.7 MPa, and after spraying, curing is carried out at 200-260°C, the curing time is 0.5-1h; polytetrafluoroethylene provides excellent corrosion resistance and wear resistance, forming a uniform and dense protective layer, prolonging the service life of the unmanned aerial vehicle wing. As the middle layer, polytetrafluoroethylene supports the top layer coating.

[0066] The top layer is sprayed with a polytetrafluoroethylene and liquid crystal polymer blend, the solid content is 15-20%, the spraying pressure is 0.4-0.7 MPa, and after spraying, curing is carried out at 150-200°C, the curing time is 15-60min; the top layer coating combines the wear resistance of polytetrafluoroethylene and the high wear resistance of liquid crystal polymer, further improving the protective performance and mechanical strength of the coating.

[0067] Preparation of polytetrafluoroethylene and liquid crystal polymer blend: mix liquid crystal polymer, polytetrafluoroethylene, compatibilizer and antioxidant with a mass ratio of 2-4:1:0.2-0.8:0.02-0.05, the mixing temperature is 320-400°C, the stirring speed is 200-600r / min, and the stirring time is 20-40min; liquid crystal polymer has excellent fluidity after melting at high temperature, forming thermal migration; the result of this thermal migration is that the liquid crystal polymer migrates and flows around the voids of the polytetrafluoroethylene in the polytetrafluoroethylene matrix to form microfibers, the microfibers are connected to form a dense and uniform three-dimensional network, tightly enveloping the polytetrafluoroethylene matrix, playing a reinforcing role, and limiting and preventing the strip-shaped wear of PTFE, making the wear of PTFE into fine particle wear, improving the wear resistance and mechanical strength of PTFE.

[0068] The liquid crystal polymer in the blend will also have a thermal migration effect on the polytetrafluoroethylene in the middle layer, firmly combining the middle layer coating with the top layer coating.

[0069] Example one

[0070] A preparation method of a reinforced and toughened bamboo fiber unmanned aerial wing, the specific steps are:

[0071] S1, select bamboo fiber and carbon fiber as raw materials, the length of bamboo fiber is 15mm, the diameter is 25μm; the length of carbon fiber is 3mm, the diameter is 7μm; mix bamboo fiber and carbon fiber according to the mass ratio of 3:1, add into the fiber mixing machine; set the rotating speed of fiber mixing machine to 900r / min, the mixing time is 25min, and mix uniformly.

[0072] S2, prepare a silane coupling agent solution with a concentration of 1%. Mix the mixture of bamboo fiber and carbon fiber mixed in step S1 with the silane coupling agent solution in a mass ratio of 1:0.02, and perform surface treatment under water bath heating conditions, with a water bath temperature of 60℃, a mixing time of 3h, and a stirring speed of 400r / min.

[0073] S3, select epoxy resin as the matrix resin. Mix the surface-treated bamboo fiber and carbon fiber mixture with the epoxy resin in a mass ratio of 1:1.3, set the mixing temperature to 28℃, the stirring speed to 300r / min, and the mixing time to 20min, so that the resin uniformly wraps the fibers to form a bamboo fiber composite material.

[0074] S4, inject the bamboo fiber composite material into the unmanned aerial wing mold at a rate of 70g / min, and perform mold pressing in a vacuum environment with a vacuum degree of-0.92mbar, a mold pressing temperature of 120℃, a mold pressing pressure of 9MPa, and a mold pressing time of 1.5h. Adopt a multi-stage heat treatment method: heat to 80℃ for 10min in the primary curing stage, heat to 115℃ for 45min in the intermediate curing stage, and heat to 140℃ for 2.5h in the final curing stage, then cool to 20℃ at a rate of 20℃ / h, and perform demolding treatment.

[0075] S5, polish the demolded unmanned aerial wing, first polish with 100 mesh coarse sandpaper for 18min, then polish with 320 mesh fine sandpaper for 25min.

[0076] Preparation of polytetrafluoroethylene and liquid crystal polymer blend: mix liquid crystal polymer, polytetrafluoroethylene, compatibilizer and antioxidant in a mass ratio of 3:1:0.5:0.03, mix at 360℃ for 30min, and stir at a speed of 400r / min.

[0077] Spray the bottom layer of the coating with epoxy primer, the solid content of the epoxy primer is 50%, the spraying pressure is 0.45MPa, and after spraying, solidify at 70℃ for 1.5h.

[0078] The intermediate layer coating is sprayed with polytetrafluoroethylene with a solid content of 12% and a spraying pressure of 0.55 MPa, and after the spraying is completed, it is cured at 230°C for 45 min.

[0079] The surface layer coating is sprayed with a polytetrafluoroethylene and liquid crystal polymer blend with a solid content of 17% and a spraying pressure of 0.55 MPa, and after the spraying is completed, it is cured at 175°C for 30 min.

[0080] Example Two

[0081] A method for preparing a reinforced and toughened bamboo fiber unmanned aerial wing, which is the same as that of Example One, and the difference between this embodiment and Example One is that;

[0082] In step S1, the bamboo fiber and the carbon fiber are mixed in a mass ratio of 2.3:1.

[0083] Example Three

[0084] A method for preparing a reinforced and toughened bamboo fiber unmanned aerial wing, which is the same as that of Example One, and the difference between this embodiment and Example One is that;

[0085] In step S1, the bamboo fiber and the carbon fiber are mixed in a mass ratio of 3.5:1.

[0086] Example Four

[0087] A method for preparing a reinforced and toughened bamboo fiber unmanned aerial wing, which is the same as that of Example One, and the difference between this embodiment and Example One is that;

[0088] In step S1, the bamboo fiber and the carbon fiber are mixed in a mass ratio of 4:1.

[0089] Example Five

[0090] A method for preparing a reinforced and toughened bamboo fiber unmanned aerial wing, which is the same as that of Example One, and the difference between this embodiment and Example One is that;

[0091] In step S5, the solid content of the intermediate layer coating sprayed with polytetrafluoroethylene is 10%.

[0092] Example Six

[0093] A method for preparing a reinforced and toughened bamboo fiber unmanned aerial wing, which is the same as that of Example One, and the difference between this embodiment and Example One is that;

[0094] In step S5, the solid content of the intermediate layer coating sprayed with polytetrafluoroethylene is 13%.

[0095] Example Seven

[0096] A preparation method of a reinforced and toughened bamboo fiber unmanned aerial wing, the same as that of embodiment one will not be repeated, and the difference between this embodiment and embodiment one is that

[0097] In step S5, the solid content of the intermediate layer coating sprayed polytetrafluoroethylene is 15%.

[0098] Example eight

[0099] A preparation method of a reinforced and toughened bamboo fiber unmanned aerial wing, the same as that of embodiment one will not be repeated, and the difference between this embodiment and embodiment one is that

[0100] In step S5, the solid content of the intermediate layer coating sprayed polytetrafluoroethylene is 15%.

[0101] Example nine

[0102] A preparation method of a reinforced and toughened bamboo fiber unmanned aerial wing, the same as that of embodiment one will not be repeated, and the difference between this embodiment and embodiment one is that

[0103] In step S5, the solid content of the intermediate layer coating sprayed polytetrafluoroethylene is 15%.

[0104] Example ten

[0105] A preparation method of a reinforced and toughened bamboo fiber unmanned aerial wing, the same as that of embodiment one will not be repeated, and the difference between this embodiment and embodiment one is that

[0106] In step S5, the solid content of the intermediate layer coating sprayed polytetrafluoroethylene is 15%.

[0107] Example eleven

[0108] A preparation method of a reinforced and toughened bamboo fiber unmanned aerial wing, the same as that of embodiment one will not be repeated, and the difference between this embodiment and embodiment one is that

[0109] In the preparation of the polytetrafluoroethylene and liquid crystal polymer blend, the mass ratio of liquid crystal polymer to polytetrafluoroethylene is 2.5:1.

[0110] Example twelve

[0111] A preparation method of a reinforced and toughened bamboo fiber unmanned aerial wing, the same as that of embodiment one will not be repeated, and the difference between this embodiment and embodiment one is that

[0112] In the preparation of the polytetrafluoroethylene and liquid crystal polymer blend, the mass ratio of liquid crystal polymer to polytetrafluoroethylene is 3.5:1.

[0113] Example thirteen

[0114] A method for preparing a reinforced and toughened bamboo fiber unmanned aerial wing, the same as that of embodiment one will not be repeated, the difference between this embodiment and embodiment one is that;

[0115] In the preparation of the polytetrafluoroethylene and liquid crystal polymer blend, the mass ratio of liquid crystal polymer to polytetrafluoroethylene is 4:1.

[0116] Comparative example one

[0117] A method for preparing a reinforced and toughened bamboo fiber unmanned aerial wing, the same as that of embodiment one will not be repeated, the difference between this embodiment and embodiment one is that;

[0118] In step S1, no carbon fiber is added.

[0119] Comparative example two

[0120] A method for preparing a reinforced and toughened bamboo fiber unmanned aerial wing, the same as that of embodiment one will not be repeated, the difference between this embodiment and embodiment one is that;

[0121] In step S5, no intermediate layer coating polytetrafluoroethylene is sprayed.

[0122] Comparative example three

[0123] A method for preparing a reinforced and toughened bamboo fiber unmanned aerial wing, the same as that of embodiment one will not be repeated, the difference between this embodiment and embodiment one is that;

[0124] In step S5, no intermediate layer coating polytetrafluoroethylene and liquid crystal polymer blend is sprayed.

[0125] Experimental example one

[0126] In this test example, the bamboo fiber plates prepared in embodiments one to thirteen and comparative examples one to three are selected for physical and chemical performance testing.

[0127] Samples are cut from the bamboo fiber plates prepared in the embodiments and comparative examples, and shear tests are performed according to ASTM D2344 standard: stretching at a constant stretching speed until the sample breaks, calculating the shear strength according to the maximum load and the cross-sectional area of the sample; applying periodic tension and compression to the sample within the elastic range, recording the stress and strain, and calculating the slope from the linear part of the stress-strain curve, i.e. the elastic modulus.

[0128] Samples are cut from the bamboo fiber plates prepared in the embodiments and comparative examples, mixed pesticides are selected as the corrosion medium, the immersion time is set to 48h, the temperature is 20℃, the mass of the sample before and after immersion is recorded, and the mass loss ratio of the sample is calculated.

[0129] Table 1 Physical properties of different experimental bamboo fiber composites

[0130]

[0131]

[0132]

[0133] From the data in the table, when the mixing ratio of bamboo fiber and carbon fiber is 3:1, the composite material exhibits the highest shear strength and elastic modulus, indicating that the reinforcing effect of carbon fiber is significant; when the solid content of the intermediate layer coating polytetrafluoroethylene is 12%, the concentration of the surface layer coating polytetrafluoroethylene is 17%, and the ratio of the polytetrafluoroethylene and liquid crystal polymer blend is 3:1, the mass loss after corrosion is the smallest, and the shear strength and elastic modulus are also enhanced compared to other ratios.

[0134] Examples 1 to 4 show the influence of different mixing ratios of bamboo fiber and carbon fiber on the performance of bamboo fiber composite material. With the increase of the proportion of bamboo fiber, the shear strength and elastic modulus show a normal distribution trend. Carbon fiber provides additional strength and rigidity, but too much carbon fiber will cause uneven dispersion between fibers, affecting the overall performance of the composite material.

[0135] Examples 1 and 5 to 7 show the influence of the solid content of the intermediate layer polytetrafluoroethylene on the performance. Properly increasing the content of polytetrafluoroethylene can improve the shear strength to a certain extent, but too high content may cause uneven coating, making the surface coating unable to adhere well, and affecting the overall corrosion performance.

[0136] Examples 1 and 8 to 13 show the influence of the solid content of polytetrafluoroethylene and the ratio of liquid crystal polymer and polytetrafluoroethylene in the surface layer coating. Within a certain range, the increase of solid content has a positive effect on performance, but too high solid content will make the coating brittle and reduce mechanical properties. When the proportion of liquid crystal polymer is moderate, too high or too low proportion will affect the performance of the coating.

[0137] Based on the ideal embodiments of the present application, through the above description, relevant personnel can make various changes and modifications without deviating from the scope of the technical idea of the present application. The technical scope of the present application is not limited to the contents of the specification, and must be determined by the scope of the claims.

Claims

1. A method for the preparation of reinforced and toughened bamboo fiber unmanned aerial wing characterized by, The method comprises the steps of: S1, cutting bamboo fibers and carbon fibers, and adding them into a fiber mixing machine for uniform mixing; S2, surface treating the mixed bamboo fibers and carbon fibers with a silane coupling agent; S3, mixing the surface treated bamboo fibers and carbon fibers with resin to form a bamboo fiber composite material; S4, injecting the mixed bamboo fiber composite material into a mold of a UAV wing for mold pressing and heat setting treatment; S5, polishing the demolded UAV wing, and performing multi-layer coating spraying and solidification treatment; In step S1, the mixing mass ratio of the bamboo fibers to the carbon fibers is 2.3-4:1; the length of the bamboo fibers is 10-25 mm, and the diameter of the bamboo fibers is 20-30 μm; the length of the carbon fibers is 1-6 mm, and the diameter of the carbon fibers is 5-10 μm; the rotating speed of the fiber mixing machine is 800-1000 r / min, and the mixing time is 20-30 min; The preparation of the polytetrafluoroethylene and liquid crystal polymer blended liquid comprises: mixing liquid crystal polymer, polytetrafluoroethylene, a compatible agent and an antioxidant with a mass ratio of 2-4:1:0.2-0.8:0.02-0.05, a mixing temperature of 320-400 ℃, a stirring speed of 200-600 r / min and a stirring time of 20-40 min; The multi-layer coating comprises: spraying an epoxy primer as a bottom layer, spraying polytetrafluoroethylene as an intermediate layer, and spraying a polytetrafluoroethylene and liquid crystal polymer blended liquid as a surface layer.

2. The method according to claim 1, wherein the method is characterized by: In step S2, the mixture of the bamboo fibers and the carbon fibers is mixed with a silane coupling agent solution with a concentration of 0.5%-1.5%, the mass ratio of the mixture to the silane coupling agent is 1:0.01-0.03, the water bath heating temperature is 50-70 ℃, the mixing time is 2-4 h, and the stirring speed is 300-500 r / min.

3. A method of making a reinforced and toughened bamboo fiber drone wing as claimed in claim 1, wherein: In step S3, the mass ratio of the mixture of the bamboo fibers and the carbon fibers to the resin is 1:1.2-1.5, the mixing temperature is 25-30 ℃, the stirring speed is 200-400 r / min, the mixing time is 15-30 min, and the resin is one or a mixture of more than one of an epoxy resin, a polyurethane resin and a phenolic resin.

4. The method of claim 1, wherein the method is characterized by: In step S4, S41, the bamboo fiber composite material is injected into the mold at a rate of 50-100 g / min, and the vacuum degree is -0.9 to -0.95 mbar; S42, during the mold pressing treatment, the mold pressing temperature is 100-150 ℃, the mold pressing pressure is 8-10 MPa, and the mold pressing time is 1-2 h; S43, the multi-stage heat setting treatment is performed at the same time as the mold pressing treatment: S44, after the heat setting, the bamboo fiber composite material is cooled to 20 ℃ at a rate of 20 ℃ / h, and demolding treatment is performed.

5. The method for preparing a reinforced and toughened bamboo fiber UAV wing according to claim 4, characterized in that: In step S43, the multi-stage heat setting treatment comprises: In the primary curing stage, the heating temperature is 70-100 ℃, and the heating time is 5-15 min; In the intermediate curing stage, the heating temperature is 100-130 ℃, and the heating time is 0.5-1 h; In the final curing stage, the heating temperature is 130-150 ℃, and the heating time is 1-4 h.

6. The method of claim 1, wherein the method is characterized by: In step S5, the surface is polished with 80-120 mesh coarse sandpaper for 15-20 minutes, and then polished with 240-400 mesh fine sandpaper for 20-30 minutes.

7. The method of claim 1, wherein the method is characterized by: In step S5, the multi-layer coating is sprayed as follows: The base layer is sprayed with an epoxy primer, the solid content of the epoxy primer being 40%-60%, the spraying pressure being 0.3-0.6 MPa, and the curing being performed at 60-80°C after spraying, the curing time being 1-2 hours; The intermediate layer is sprayed with polytetrafluoroethylene, the solid content of the polytetrafluoroethylene being 10%-15%, the spraying pressure being 0.4-0.7 MPa, and the curing being performed at 200-260°C after spraying, the curing time being 0.5-1 hour; The surface layer is sprayed with a blend of polytetrafluoroethylene and liquid crystal polymer, the solid content being 15-20%, the spraying pressure being 0.4-0.7 MPa, and the curing being performed at 150-200°C after spraying, the curing time being 15-60 minutes.

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