A lightweight strong fiber composite material imitating the scales of coelacanth and a method for preparing the same

Abstract

The present application belongs to the field of bionic composite material structure engineering, and discloses a light and tough fiber composite material imitating the scales of coelacanth and a preparation method thereof. The composite material comprises a polymer matrix and a double-helix structure fiber layer skeleton embedded in the polymer matrix, wherein the double-helix structure fiber layer skeleton comprises a plurality of hole structure fiber layers, the hole structure fiber layers are arranged in a double-helix and stacked in sequence, each hole structure fiber layer comprises a plurality of first fibers and a plurality of second fibers filled between layers, and the diameter of the second fibers is smaller than that of the first fibers. The double-helix structure and inter-beam fibers of the scales of coelacanth are imitated, the hole structure fiber layers are stacked, isotropy in multiple directions of the fiber layer plane is increased, the stacked arrangement disperses and expands cracks, and the strength and impact resistance of the composite material are improved. The second fibers act as adhesive materials, constrain the delamination of the hole structure fiber layers, enhance the interlayer bonding performance, and obtain a fiber composite material with light weight and high toughness.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of bionic engineering composite materials, and particularly relates to a light-weight and strong-tough fiber composite material imitating the scales of a coelacanth and a preparation method thereof. BACKGROUND

[0002] Composite materials can improve or overcome the weaknesses of single materials, fully exert the advantages of each material, and are widely applied in the fields of national defense industry, aerospace, rail transportation, and building engineering, and have broad market prospects and great development potential. Among them, fiber composite materials are one of the most widely used composite materials due to their high specific strength, high specific modulus, corrosion resistance, and easy design. However, there are still many major problems and challenges in the research of fiber composite materials at present.

[0003] Traditional fiber composite materials have a laminated structure, poor interlaminar bonding, low interlaminar shear strength, and are prone to delamination failure. The laminated angle is single, and when subjected to impact load, cracks are easily transmitted between layers, fibers are easily broken, and other damages occur, resulting in insufficient overall toughness of the fiber composite material. Therefore, developing fiber composite materials that meet the requirements of strength and toughness is one of the important tasks of modern material engineering, and on this basis, lightweight of fiber composite materials is also a problem to be solved. SUMMARY

[0004] The present application aims to provide a light-weight and strong-tough fiber composite material imitating the scales of a coelacanth and a preparation method thereof to solve the problems raised in the background. The present application imitates the double helix structure and interlaminar fiber of the scales of a coelacanth, uses a directional freeze casting method to construct a fiber layer skeleton with a double helix structure, and combines with interlaminar second fibers to solve the problems of poor mechanical properties and delamination failure caused by the single laminated angle of traditional fiber composite materials.

[0005] The technical solutions of the present application are as follows:

[0006] In a first aspect of the present application, a light-weight and strong-tough fiber composite material imitating the scales of a coelacanth is provided, which comprises:

[0007] a fiber layer skeleton with a double helix structure and a polymer matrix; the fiber layer skeleton with a double helix structure is embedded in the polymer matrix;

[0008] The fiber layer skeleton with a double helix structure comprises: a plurality of hole structure fiber layers, a plurality of the hole structure fiber layers are arranged in a double helix and stacked in sequence, the hole structure fiber layer comprises: a plurality of first fibers, there are a plurality of second fibers in the hole structure of the hole structure fiber layer and between adjacent two hole structure fiber layers, the diameter of the second fibers is smaller than the diameter of the first fibers.

[0009] The lightweight and strong fiber composite material imitating the scales of coelacanth, wherein the fiber layer skeleton in the double helix structure comprises a plurality of fiber layer groups in orthogonal double-layer hole structures, and the fiber layer groups in orthogonal double-layer hole structures are arranged in a periodic manner from top to bottom in a clockwise rotation of 30 degrees.

[0010] The lightweight and strong fiber composite material imitating the scales of coelacanth, wherein the fiber layer groups in orthogonal double-layer hole structures imitate the scales of coelacanth, and the fiber layer groups in orthogonal double-layer hole structures are arranged in a periodic manner from top to bottom in a clockwise rotation of 30 degrees.

[0011] The lightweight and strong fiber composite material imitating the scales of coelacanth, wherein the second fibers between the two adjacent hole structure fiber layers imitate the interlaced fibers in the scales of coelacanth and are used as adhesive materials.

[0012] The lightweight and strong fiber composite material imitating the scales of coelacanth, wherein the first fibers have a length of microns and are selected from one or more of carbon fibers, cellulose fibers, aramid fibers, basalt fibers, glass fibers, and carbon nanotubes.

[0013] The lightweight and strong fiber composite material imitating the scales of coelacanth, wherein the second fibers are selected from organic fibers or inorganic fibers, and the length of the second fibers is less than the length of the first fibers in the same piece.

[0014] The lightweight and strong fiber composite material imitating the scales of coelacanth, wherein the polymer matrix is selected from thermosetting resins or thermoplastic resins.

[0015] In a second aspect, the embodiment of the present application provides a preparation method of the lightweight and strong fiber composite material imitating the scales of coelacanth, wherein the method comprises the following steps:

[0016] Providing a polymer solution, a mixed solution of second fibers, and a mixed solution of a plurality of portions of first fibers;

[0017] For each portion of the mixed solution of the first fibers, a directional freeze casting method is used to inject the mixed solution of the first fibers into a first mold, freeze, and demold to obtain a hole structure fiber layer frozen sample;

[0018] All the hole structure fiber layer frozen samples are sequentially stacked in a second mold in a double helix, and the mixed solution of the second fibers is injected into the second mold, frozen, and demolded to obtain a double helix structure fiber layer skeleton after freeze-drying;

[0019] The polymer solution is vacuum cast in the double helix structure fiber layer skeleton, and a lightweight and strong fiber composite material imitating the scales of coelacanth is obtained after solidification.

[0020] The preparation method of the light-weight and strong fiber composite material imitating the scales of coelacanth, wherein the first mold comprises a substrate and a three-dimensional tube arranged on the substrate; the thermal conductivity of the substrate is 2000 times or more than that of the three-dimensional tube; for each portion of the mixed solution of the first fibers, the mixed solution of the first fibers is injected into the first mold and frozen, and a pore structure fiber layer frozen sample is obtained after demolding, comprising:

[0021] For each portion of the mixed solution of the first fibers, a release agent is sprayed in the first mold, the mixed solution of the first fibers is injected into the first mold, and the substrate is placed on the surface of a cold source for freezing and demolding to obtain a pore structure fiber layer frozen sample.

[0022] The preparation method of the light-weight and strong fiber composite material imitating the scales of coelacanth, wherein the first mold comprises a substrate and a three-dimensional tube arranged on the substrate; the thermal conductivity of the substrate is 2000 times or more than that of the three-dimensional tube; for each portion of the mixed solution of the first fibers, the mixed solution of the first fibers is injected into the first mold and frozen, and a pore structure fiber layer frozen sample is obtained after demolding, comprising:

[0023] All the pore structure fiber layer frozen samples are stacked into the second mold, and the angle θ of each pore structure fiber layer frozen sample is:

[0024]

[0025] Wherein, θ represents the angle of the pore structure fiber layer frozen sample, α represents the rotation angle, and n represents the layer number of the pore structure fiber layer frozen sample;

[0026] The mixed solution of the second fibers is injected into the second mold and frozen, and a fiber layer skeleton frozen sample is obtained after demolding;

[0027] The fiber layer skeleton frozen sample is cut and freeze-dried to obtain a double-helix structure fiber layer skeleton.

[0028] The beneficial effects of the present application are as follows:

[0029] This invention provides a lightweight, high-strength fiber composite material inspired by coelacanth scales and its preparation method. The biomimetic coelacanth scale double-helix structure is achieved by preparing a single-layer porous fiber layer through directional cryogenic casting, arranging and stacking them according to an orthogonal double-helix "Bouligand" structure. The interlayer gaps are filled with micro / nanofiber as a bonding material, forming a unified fiber skeleton structure. The orthogonal double-layer porous fiber layer provides isotropy in multiple directions, preventing unidirectional crack propagation, increasing crack propagation paths, and consuming more impact energy during fiber debonding, pull-out, and fracture. Simultaneously, the randomly distributed micro / nanofiber in the interlayers provides a certain degree of constraint on the single-layer porous fiber layer, producing more complex crack tip morphologies and suppressing interlayer delamination. Furthermore, the porous structure of the fiber layer itself is lightweight and exhibits a certain degree of flexible elastic strain under external loads, absorbing some energy. In summary, this invention, by setting a double-helix fiber layer skeleton and using randomly distributed micro / nanofiber to constrain the single-layer porous fiber layer, obtains a lightweight, high-strength, and tough fiber composite material. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the overall structure of a lightweight and strong fiber composite material that mimics the scales of a coelacanth, according to the present invention.

[0031] Figure 2 for Figure 1 A schematic diagram of the fiber layer assembly with orthogonal double-layer pore structure in region A;

[0032] Figure 3 A schematic diagram of the double helix structure arrangement of a lightweight and tough fiber composite material that mimics the scales of a coelacanth.

[0033] Figure 4 This is a cross-sectional view of a fiber layer assembly with an orthogonal double-layer pore structure.

[0034] Figure 5 for Figure 4 Enlarged schematic diagram of the structure in area B;

[0035] Figure 6 for Figure 5 Enlarged schematic diagram of the structure in area C;

[0036] Figure 7 This is a schematic diagram of a lightweight and tough fiber composite polymer matrix for imitating coelacanth scales according to the present invention.

[0037] Explanation of reference numerals in the attached figures:

[0038] 10. Double helix fiber layer skeleton; 11. Porous fiber layer; 12. Porous fiber layer; 13. Inter-bundle fiber layer; 110. First fiber; 130. Second fiber; 20. Polymer matrix. Detailed Implementation

[0039] The technical solutions of the present invention will be further described in detail below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0040] Traditional fiber composites are prone to interlaminar crack propagation under impact loads, leading to delamination failure and poor interlaminar toughness. However, many natural materials exhibit a combination of lightweight, high strength, and high toughness, providing insights for the design and fabrication of composite materials. Inspired by the scales of the coelacanth, this invention extracts the double-helix "Bouligand" structure from these scales and uses directional cryogenic casting to prepare a fiber layer skeleton with a double-helix "Bouligand" structure. Single-layer porous fiber layers are orthogonally laid perpendicular to the pore axis to form an orthogonal double-layer porous fiber layer assembly, which rotates in a step pattern across the entire thickness to form a double-helix "Bouligand" structure. This structure can significantly increase the crack propagation path, prevent the propagation of translaminar cracks in the interlaminar plane, and promote the dispersion of more stress to adjacent layers, thus enhancing the material's toughness. The interlaminar constraint characteristics of the fibers between the coelacanth scale bundles are extracted, and micro / nanofibers are randomly distributed between layers to prevent crack propagation, inhibit fiber layer delamination, and effectively improve interlaminar toughness, thereby achieving a balance between strength and toughness.

[0041] The coelacanth, often called a "living fossil" of the ocean, has existed for approximately 400 million years. Research has revealed that its resistance to predators is due to the rare double-helix "Bouligand" structure of its scales. The adjacent fiber layers of the coelacanth's scales are orthogonally arranged, providing excellent penetration resistance and effectively resisting the intrusion of predator teeth. Upon impact, the collagen fibers in the scales bridge, stretch, delaminate, and break to absorb some of the impact energy. The double-helix "Bouligand" structure allows the collagen fibers to be widely distributed in multiple directions. Under tension, the collagen fibers deflect and slide to withstand greater loads. Unique inter-bundle fibers exist between the collagen fiber layers of the scales, acting as an adhesive to inhibit delamination. Even in relatively weaker interlayers, a certain degree of sliding occurs to enhance toughness. The coelacanth effectively resists predator attacks and enhances its survival ability through its unique double-helix "Bouligand" structure.

[0042] Inspired by the scales of the coelacanth, this invention provides a lightweight and strong fiber composite material that mimics the scales of the coelacanth, such as... Figures 1-7 As shown. Figure 1 and Figure 4As shown, the fiber composite material comprises: a double helix structure fiber layer skeleton 10 and a polymer matrix 20, the double helix structure fiber layer skeleton 10 is embedded in the polymer matrix 20. The double helix structure fiber layer skeleton 10 comprises: a plurality of hole structure fiber layers (11, 12), a plurality of hole structure fiber layers (11, 12) are arranged in a double helix structure, the hole structure fiber layer (11, 12) comprises: a plurality of first fibers 110, a plurality of second fibers 130 exist in the hole structure of the adjacent two hole structure fiber layers (11, 12) and between the adjacent two hole structure fiber layers (11, 12), and the diameter of the second fiber 130 is smaller than the diameter of the first fiber 110.

[0043] Specifically, the double helix structure fiber layer skeleton 10 is formed by a plurality of hole structure fiber layers (11, 12) stacked in sequence, specifically in a double helix structure, the odd layer hole structure fiber layer is spirally stacked in sequence, the even layer hole structure fiber layer is spirally stacked in sequence, and then the double helix structure is formed. The hole structure fiber layer (11, 12) comprises a plurality of first fibers 110, the hole structure in the hole structure fiber layer penetrates through both ends of the hole structure fiber layer, and the hole structure can be multiple, which can be randomly distributed or arrayed. A plurality of second fibers 130 exist between the adjacent two hole structure fiber layers, and a plurality of second fibers 130 can also exist in the hole structure of the hole structure fiber layer. The diameter of the second fiber 130 is smaller than the diameter of the first fiber 110.

[0044] Specifically, the double helix structure fiber layer skeleton 10 increases isotropy from multiple directions, the misaligned hole structure fiber layers disperse the propagation of cracks, promote their propagation in multiple hole structure fiber layers, prolong the crack propagation path, and significantly improve the fracture toughness; when subjected to tensile, bending or shear stress, the double helix structure fiber layer can adjust the rotation angle to a certain extent, adapt to the stress dispersed in the plane, and when the stress increases and cracks appear, the fiber is stretched along the direction of crack propagation, delaminated from the polymer matrix 20, and broken. A large number of first fibers exist in the hole structure fiber layer, which greatly enhances the energy dissipation capacity of the material; the hole structure fiber layer arranged in a double helix structure can significantly enhance the penetration resistance of the material and avoid catastrophic failure. The second fibers 130 are randomly distributed between the adjacent two hole structure fiber layers, which can constrain the hole structure fiber layer, inhibit the excessive rotation of the hole structure fiber layer and cause delamination failure, effectively prevent crack propagation, increase crack deflection, and enhance material strength and toughness.

[0045] The second fibers 130 between the adjacent two hole structure fiber layers are similar to the inter-beam fibers in the scales of the coelacanth, which can be used as adhesive materials.

[0046] As Figure 1 and Figure 7As shown, the polymer matrix 20 comprises a thermosetting resin or a thermoplastic resin, which is molded at a preset curing temperature, pressure and time.

[0047] As shown, the fiber layer skeleton 10 of the double helix structure comprises a plurality of fiber layer groups of orthogonal double-layer hole structures, which are arranged in sequence from top to bottom with a rotation period, and each fiber layer group of the orthogonal double-layer hole structure comprises two hole structure fiber layers, and the hole axes of the two hole structure fiber layers are orthogonal. Figure 1 Figure 2 As shown, the fiber layer skeleton 10 of the double helix structure comprises a plurality of fiber layer groups of orthogonal double-layer hole structures, which are arranged in sequence from top to bottom with a rotation period, and each fiber layer group of the orthogonal double-layer hole structure comprises two hole structure fiber layers, and the hole axes of the two hole structure fiber layers are orthogonal.

[0048] Specifically, two hole structure fiber layers can be a fiber layer group of orthogonal double-layer hole structure, the odd-numbered hole structure fiber layers are sequentially spiraled, and the even-numbered hole structure fiber layers are sequentially spiraled, but the rotation angle of the odd-numbered hole structure fiber layers is the same as that of the even-numbered hole structure fiber layers, the included angle between the odd-numbered hole structure fiber layers and the corresponding even-numbered hole structure fiber layers is fixed, for example, the odd-numbered hole structure fiber layers and the corresponding even-numbered hole structure fiber layers are stacked in an orthogonal manner (the odd-numbered hole structure fiber layers and the corresponding even-numbered hole structure fiber layers belong to one fiber layer group of orthogonal double-layer hole structure). Then the angle θ of each hole structure fiber layer is:

[0049]

[0050] Wherein, θ represents the angle of the hole structure fiber layer, α represents the rotation angle, and n represents the layer number of the hole structure fiber layer.

[0051] The fiber layer group of the orthogonal double-layer hole structure is a bionic chambered spine fish scale, and the fiber layer group of the orthogonal double-layer hole structure is arranged in sequence from top to bottom with a rotation period of 30° clockwise.

[0052] Specifically, the fiber layer skeleton 10 of the double helix structure is arranged in sequence from top to bottom with a rotation period of the fiber layer group of the orthogonal double-layer hole structure, and the rotation angle α can be 30° clockwise to imitate the chambered spine fish scale, the rotation period is an integer multiple of 180°, and the period number is greater than or equal to 1. The rotation angle of the hole structure fiber layer is 0°, 90°, 30°, 120°, 60°, 150°, 90°, 180°, 120°, 210°, 150°, 240°, 180°, 270° in sequence. Specifically, as shown in the figure, the fiber layer group of the orthogonal double-layer hole structure is arranged in sequence from top to bottom with a rotation period of 30° clockwise, and the rotation period is 180°. There are 7 fiber layer groups of the orthogonal double-layer hole structure in total. The two hole structure fiber layers in the fiber layer group of the orthogonal hole structure are arranged orthogonally based on the hole axis direction, as shown in the figure. Figure 3 Figure 4 ​​The hole structure fiber layer 11 and the hole structure fiber layer 12 are orthogonally arranged, and are essentially the same, and the difference only exists in the arrangement angle. The hole structure fiber layer comprises a plurality of first fibers 110, and is similar to a honeycomb structure as a whole. The hole structure is randomly distributed or arranged, can greatly reduce the material mass, and achieves the purpose of lightweight performance. The length of the first fiber 110 is micron level, and can be less than or equal to 1 micron. The first fiber can be one or more of carbon fiber, cellulose fiber, aramid fiber, basalt fiber, glass fiber and carbon nanotube.

[0053] As shown in Figure 5 , inspired by the inter-bundle fibers of the coelacanth scale, the inter-bundle fiber layer 13 is arranged between the double helix structure fiber layers and acts as an adhesive material. Specifically, as shown in Figure 6 , the inter-bundle fiber layer 13 comprises a plurality of second fibers 130, which can be organic fibers and inorganic fibers. In a certain specific sample, the size of the second fiber 130 is smaller than that of the first fiber 110 in the hole structure fiber layer. The second fiber 130 is randomly distributed between all the hole structure fiber layers, and plays a role in restraining the hole structure fiber layer. It can inhibit the hole structure fiber layer from over-rotating and thus delaminating and failing, effectively prevent crack propagation, increase crack deflection and deflection, and enhance material strength and toughness.

[0054] The application also provides a preparation method of the lightweight and tough fiber composite material imitating the coelacanth scale, comprising the following steps:

[0055] S1, providing a polymer solution, a mixed solution of second fibers and a mixed solution of a plurality of first fibers;

[0056] S2, for each portion of the mixed solution of the first fibers, the mixed solution of the first fibers is injected into a first mold and frozen, and a hole structure fiber layer frozen sample is obtained after demolding;

[0057] S3, all the hole structure fiber layer frozen samples are sequentially stacked in a second mold in a double helix, and the mixed solution of the second fibers is injected into the second mold and frozen. After demolding, a double helix structure fiber layer skeleton is obtained after freeze-drying;

[0058] S4, vacuum casting the polymer solution in the double helix structure fiber layer skeleton, and solidifying to obtain the lightweight and tough fiber composite material imitating the coelacanth scale.

[0059] Specifically, the polymer solution comprises a polymer and a corresponding solvent, the polymer comprises an epoxy resin, and the epoxy resin can be E51 epoxy resin (including A glue and B glue). The mixed solution of the first fibers comprises the first fibers, a binder, a dispersant, a rheological agent, and a corresponding solvent. The mixed solution of the second fibers comprises the second fibers, a binder, a dispersant, a rheological agent, and a corresponding solvent. The mixed solution of the first fibers is divided into several portions, and each portion of the mixed solution of the first fibers forms a pore structure fiber layer frozen sample, and each pore structure fiber layer frozen sample is prepared by the same method. The plurality of pore structure fiber layer frozen samples are sequentially stacked in a double helix, and the mixed solution of the second fibers is injected, so that the mixed solution of the second fibers is immersed in all the pore structure fiber layers. The mixed solution of the second fibers can be filled between the adjacent two pore structure fiber layer frozen samples, and can also be filled in the pores of the peripheral part of the pore structure fiber layer frozen sample in contact with the mixed solution of the second fibers. When the mixed solution of the second fibers is injected, the pore structure fiber layer frozen sample will not (massively) thaw due to the low temperature of the pore structure fiber layer frozen sample. In order to make the mixed solution of the second fibers fully filled, the mixed solution of the second fibers can be heated to a preset temperature (such as 30-60 DEG C) before being injected into the second mold. The mixed solution of the second fibers will not freeze immediately after contacting the pore structure fiber layer frozen sample, and still has a certain flowability, which is convenient for full filling. After the mixed solution of the second fibers is frozen, it is demolded and freeze-dried to obtain a double-helix structure fiber layer skeleton. The solvent (including the solvent in the mixed solution of the first fibers and the solvent in the mixed solution of the second fibers) is removed by freeze-drying. The double-helix structure fiber layer skeleton does not contain the solvent. Finally, the polymer solution is poured into the double-helix structure fiber layer skeleton, and a lightweight and strong fiber composite material imitating the scales of a coelacanth is obtained after the polymer is solidified.

[0060] The binder comprises at least one of polyvinyl alcohol (PVA) and polyethylene glycol (PEG); the dispersant comprises at least one of an anionic dispersant, a non-ionic dispersant, and a high-molecular dispersant; and the rheological agent comprises at least one organic rheological agent.

[0061] The first mold comprises a substrate and a three-dimensional pipe arranged on the substrate, and the thermal conductivity of the three-dimensional pipe is far less than the thermal conductivity of the substrate, and the thermal conductivity of the substrate is 2000 times or more than the thermal conductivity of the three-dimensional pipe.

[0062] The step S2 specifically comprises:

[0063] S21, for each portion of the mixed solution of the first fibers, spraying a release agent in the first mold, injecting the mixed solution of the first fibers into the first mold, and placing the substrate on the surface of the cold source to be frozen and demolded to obtain a pore structure fiber layer frozen sample.

[0064] Specifically, the hole structure fiber layer frozen sample is prepared by using the method of directional freeze casting, so that the first fibers are arranged in the freezing process, thereby improving the strength and toughness of the composite material. The first mold can be prepared by using 3D printing technology, and the material used is a plastic with a low thermal conductivity, for example, polylactic acid (PLA). The substrate is located on the surface of the cold source, and the substrate will quickly cool down due to its large thermal conductivity. The stereotube cannot cool down quickly due to its small thermal conductivity. The part of the stereotube close to the substrate cools down first, and the part of the stereotube far from the substrate cools down later, thereby forming a temperature field with a gradient. The mixed solution of the first fibers is oriented and frozen, the ice crystals grow along the length direction of the stereotube, and the first fibers are excluded and pressed between the ice crystals to form the oriented hole structure fiber layer skeleton.

[0065] The step S3 specifically includes:

[0066] S31, stack all the hole structure fiber layer frozen samples into the second mold, and the angle θ of each hole structure fiber layer frozen sample is:

[0067]

[0068] wherein θ represents the angle of the hole structure fiber layer frozen sample, α represents the rotation angle, and n represents the layer number where the hole structure fiber layer frozen sample is located.

[0069] S32, inject the mixed solution of the second fibers into the second mold and freeze, and demold to obtain a fiber layer skeleton frozen sample;

[0070] S33, cut the fiber layer skeleton frozen sample and freeze dry to obtain a double helix structure fiber layer skeleton.

[0071] Specifically, the second mold can be a silica gel mold. When the hole structure fiber layer frozen samples are stacked, the angles of the hole structure fiber layer frozen samples are not completely the same. The hole structure fiber layer frozen samples of odd layers are rotated in sequence, the hole structure fiber layer frozen samples of even layers are rotated in sequence, and the angles between the hole structure fiber layer frozen samples of odd layers and the corresponding hole structure fiber layer frozen samples of even layers are different by 90°. After obtaining the fiber layer skeleton frozen sample, the fiber layer skeleton frozen sample is cut. Since the hole structure fiber layer frozen sample is a cube, after rotation, the non-overlapping part can be cut off, and the overlapping part is reserved. Finally, freeze drying is performed to obtain a double helix structure fiber layer skeleton.

[0072] Specific application examples:

[0073] (1) A single-layer pore structure fiber layer was prepared by directional freeze casting method. A 3D printed PLA material rectangular tube mold with dimensions of 60 mm long, 1 mm wide, and 60 mm high was used. The mold was sprayed with a release agent and adhered to the surface of a copper sheet to obtain a directional freeze casting mold. An appropriate amount of micron-sized carbon fiber powder, binder, dispersant, and rheological agent were dissolved in water, magnetically stirred until uniform, and ultrasonically degassed to obtain a fiber mixture solution. The fiber mixture solution was injected into the mold and placed on the surface of a -90°C cold source for freezing. After freezing, the mold was removed in a -20°C refrigerator to obtain a single-layer pore structure fiber layer freeze sample. Fourteen single-layer pore structure fiber layer freeze samples were prepared using the above method.

[0074] (2) A double helix structure fiber layer skeleton was prepared by secondary freeze casting method. The 14-layer single-layer pore structure fiber layer freeze sample obtained in the previous step was stacked and arranged from top to bottom at angles of 0°, 90°, 30°, 120°, 60°, 150°, 90°, 180°, 120°, 210°, 150°, 240°, 180°, and 270°, and placed in a silica gel mold.

[0075] An appropriate amount of carbon nanotubes, binder, dispersant, and rheological agent were dissolved in water, stirred until uniform, and ultrasonically degassed to obtain a carbon nanotube mixture solution. The carbon nanotube mixture solution was heated to 40°C and poured into the silica gel mold, with the liquid surface level with the uppermost single-layer pore structure fiber layer. The mold was placed in a -20°C refrigerator until the entire freeze was complete, then removed. The freeze sample was cut into a strip-shaped test sample size and placed in a freeze dryer for 72 hours to obtain a double helix structure fiber layer skeleton.

[0076] (3) E51 epoxy resin was vacuum cast into the prepared double helix structure fiber layer skeleton. According to a 3:1 mass ratio, low viscosity E51 epoxy resin A and B were mixed and cast onto the double helix structure fiber layer skeleton. Vacuum was maintained for 1 hour, and the mixture was cured at 60°C for 4 hours to obtain a lightweight and tough fiber composite material resembling a cavity-based spine fish scale.

[0077] In summary, the present application provides a lightweight and strong fiber composite material imitating the scales of coelacanth and a preparation method thereof, comprising a fiber layer skeleton with double helix structure and a polymer matrix. The fiber layer skeleton with double helix structure imitates the unique orthogonal double helix arrangement of collagen fibers in the scales of coelacanth and the loosely packed inter-beam fibers between the collagen fiber layers, a single-layer pore structure fiber layer is prepared by a freeze casting method, is arranged according to the arrangement order of the collagen fibers in the scales of coelacanth, and the micro-nano fibers are randomly arranged between the fiber layers by secondary freeze casting as a bonding material between the fiber layers. This structure not only has the characteristics of ultra-lightness, but also greatly absorbs impact energy when subjected to impact load, the fibers in the single-layer pore structure fiber layer slide, bridge and stretch, the orthogonal double-layer "Bouligand" structure effectively disperses stress, and cracks are forced to conduct and deflect in multiple fiber layers, thereby effectively preventing crack propagation and enhancing material strength and toughness. The lightweight and strong fiber composite material imitating the scales of coelacanth can achieve the performance of lightweight, high strength and toughness, solves the defects of single layering and easy delamination of impact of traditional fiber composite materials, and provides a new idea for the design and preparation of new high-performance fiber composite materials.

[0078] Although the embodiments of the present application have been shown and described, it will be understood by those skilled in the art that modifications and changes can be made without departing from the principles and spirit of the present application, and all such modifications and changes shall fall within the scope of protection of the appended claims of the present application.

Claims

1. A lightweight strong fibrous composite material imitating scales of coelacanth, characterized by, The application relates to a lightweight and high-strength fiber composite material imitating a coelacanth scale. The fiber layer framework of the double helix structure is embedded in the polymer matrix. The fiber layer framework of the double helix structure comprises a plurality of hole structure fiber layers which are arranged in a double helix in sequence, the hole structure fiber layer comprises a plurality of first fibers, a plurality of second fibers are arranged in the hole structure of the hole structure fiber layer and between adjacent two hole structure fiber layers, and the diameter of the second fibers is smaller than that of the first fibers. The fiber layer framework of the double helix structure comprises a plurality of fiber layer groups of orthogonal double-layer hole structures, the fiber layer groups of the orthogonal double-layer hole structures are arranged in a rotating cycle from top to bottom, the fiber layer group of the orthogonal double-layer hole structure comprises two hole structure fiber layers, and the hole axis directions of the two hole structure fiber layers are orthogonal; the second fibers between adjacent two hole structure fiber layers imitate the inter-beam fibers in a coelacanth scale and are used as adhesive materials. The fiber layer group of the orthogonal double-layer hole structure imitates a coelacanth scale, and the fiber layer group of the orthogonal double-layer hole structure is arranged in a 30-degree clockwise rotation layer by layer from top to bottom.

2. The lightweight strong fibrous composite material that imitates scales of coelacanths according to claim 1, characterized in that, The length of the first fibers is micron level, and the first fibers are selected from one or more of carbon fibers, cellulose fibers, aramid fibers, basalt fibers, glass fibers and carbon nanotubes.

3. The lightweight strong fibrous composite material that imitates scales of coelacanths according to claim 1, characterized in that, The second fibers are selected from organic fibers or inorganic fibers.

4. The lightweight strong fibrous composite material that imitates scales of coelacanths according to claim 1, characterized in that, The polymer matrix is selected from thermosetting resins or thermoplastic resins.

5. The lightweight strong fibrous composite material that imitates scales of coelacanths according to claim 1, characterized in that, The application relates to a lightweight and high-strength fiber composite material imitating a coelacanth scale.

6. A process for the production of a lightweight strong fibrous composite material imitating scales of coelacanths according to any one of claims 1 to 5, characterized in that, The application relates to a lightweight and high-strength fiber composite material imitating a coelacanth scale. The application relates to a lightweight and high-strength fiber composite material imitating a coelacanth scale. The application relates to a lightweight and high-strength fiber composite material imitating a coelacanth scale. The first mold comprises a substrate and a three-dimensional pipe arranged on the substrate; the thermal conductivity coefficient of the substrate is 2000 times or higher than that of the three-dimensional pipe; for each portion of the first fiber mixed solution, the first fiber mixed solution is injected into the first mold and frozen, and the hole structure fiber layer frozen sample is obtained after demolding. For each portion of the first fiber mixed solution, a demolding agent is sprayed in the first mold, the first fiber mixed solution is injected into the first mold, and the substrate is placed on the surface of a cold source to be frozen and demolded, so that the hole structure fiber layer frozen sample is obtained.

7. The process for the production of light weight strong fibrous composites of imitated coelacanth scale according to claim 6, characterized in that, The application relates to a lightweight and high-strength fiber composite material imitating a coelacanth scale. The application relates to a lightweight and high-strength fiber composite material imitating a coelacanth scale.

8. The process for the production of light weight strong fibrous composites emulating scales of acanthodian fish as claimed in claim 7 wherein, The application relates to a lightweight and high-strength fiber composite material imitating a coelacanth scale. The all-pore structure fibrous layer cold sample pieces are stacked into the second mold, and the angle of each all-pore structure fibrous layer cold sample piece is 0° ​ is: ； wherein, ​ denotes the angle of the hole structure fiber layer frozen sample, α denotes the rotation angle, n denotes the layer number where the hole structure fiber layer frozen sample is located; After the second fiber mixed solution is injected into the second mold, the second fiber mixed solution is frozen, and the fiber layer skeleton frozen sample is demolded; The fiber layer skeleton frozen sample is cut and freeze-dried to obtain a fiber layer skeleton with a double helix structure.

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