A lightweight, high-strength transparent material

Abstract

The present invention discloses a lightweight, high-strength transparent material comprising a nanomaterial framework and a resin filled within the framework. To ensure the material's light transmittance, the refractive index of the resin matches that of the rigid elements. More importantly, the nanomaterial framework is composed of an orderly assembly of two-dimensional rigid elements, which are chemically bonded to the resin to reduce the interface between inorganic and organic materials. The resulting lightweight, high-strength transparent material exhibits lightness, high strength, high modulus, high toughness, and high transparency, and can be produced on a large scale.

Description

Technical Field

[0001] The present invention relates to a new high-performance material, in particular to a light-weight, high-strength and transparent material. Background Art

[0002] From electronic display screens, windshields, optical fibers to submarine observation windows and bulletproof glass, transparent materials are widely used in daily production and life as well as in the military and other fields. These application scenarios require that the materials have not only excellent optical properties, but also tough mechanical properties so that they can withstand wear and stress concentration during use. Currently, commonly used transparent materials are inorganic glass and transparent polymers such as polymethyl methacrylate, polystyrene, and polycarbonate. However, inorganic glass is prone to brittle fracture, while transparent polymers have a low modulus and are prone to wear. These problems will affect the reliability of transparent materials during long-term use. Therefore, the development of bulk materials that have high strength, toughness, and wear resistance while maintaining optical transparency is crucial to the realization of next-generation electronic devices and structural components.

[0003] Composite materials have long been favored because they can combine the multiple properties of single-component materials. In particular, some bio-composite materials assemble originally weaker building blocks through a hierarchical structure to form a variety of unique properties. For example, the unique "brick-mud" structure of shells enables them to achieve high-strength and high-toughness mechanical properties, and also provides new ideas for the preparation of lightweight, high-strength composite materials.

[0004] In recent years, researchers have developed a variety of methods to prepare high-strength, transparent shell-like composite materials, including filtration and centrifugation. To achieve good optical properties in composite materials, it is often necessary to select organic and inorganic phases with matching refractive indices. For example, by adding a dopant, phenanthrene, to the organic phase, polymethyl methacrylate (PMMA), the refractive index can be adjusted to match that of the inorganic phase, glass nanosheets, thereby achieving transparent optical properties. Filtration can produce a glass nanosheet skeleton with an oriented structure. This is then sintered to form a bridge structure, and then filled with phenanthrene-doped PMMA to produce a composite material. However, this method produces a poorly oriented skeleton. The low degree of orientation introduces a large number of inorganic-organic interfaces within the composite material, which in turn affects further improvements in the material's transmittance and mechanical properties. Furthermore, the filtration method limits the large-scale production of composite materials. The centrifugation method utilizes the shear force of the centrifugal process to orient the glass nanosheets in PMMA. However, this method suffers from difficulties in increasing the filling amount and low orientation. Although high transmittance is achieved, the improvement in mechanical properties is limited. Furthermore, the centrifugation method is limited by the limitations of the centrifugal equipment and is difficult to achieve on a large scale. Therefore, there is an urgent need to develop a new method for large-scale preparation of lightweight, high-strength transparent materials that can achieve high transmittance while meeting the requirements of excellent mechanical properties. Summary of the Invention

[0005] The purpose of the present invention is to provide a light-weight, high-strength and transparent material to address the deficiencies of the prior art.

[0006] The objectives of the present invention are achieved through the following technical solutions: a lightweight, high-strength transparent material comprising a nanomaterial skeleton and a resin filled in the nanomaterial skeleton; to ensure the light transmittance of the material, the refractive index of the resin matches the refractive index of the rigid element; more importantly, the nanomaterial skeleton is orderly assembled from two-dimensional rigid elements, and the two-dimensional rigid elements are connected to the resin through chemical bonds to reduce the interface between inorganic and organic matter.

[0007] The present invention can use transparent rigid elements, such as glass nanosheets and mica nanosheets.

[0008] In order to match the refractive index of the resin with that of the rigid element, the refractive index of the resin is generally adjusted by a dopant; the dopant is a small molecule organic compound containing electrons, such as phenanthrene and biphenyl. This electron-rich small molecule organic compound contains a large number of easily polarizable p electrons, which can increase the refractive index.

[0009] The filling method of the above-mentioned resin can be: the resin is obtained by injecting a solution of a precursor into the skeleton and then polymerizing it; before injecting the precursor, the two-dimensional rigid elements of the skeleton are surface modified so that the two-dimensional rigid elements form a chemical bond connection with the resin; the precursor is a prepolymer resin or a high molecular monomer.

[0010] For example, the aforementioned chemical bond connection is achieved through the following two-step method: the nanomaterial skeleton composed of glass sheets is first treated with a silane coupling agent to connect double bonds on the surface; then a precursor solution containing the monomer methyl methacrylate and the initiator azobisisobutyronitrile is injected between the glass sheet skeleton layers to simultaneously initiate a polymerization reaction, thereby achieving a chemical bond connection between the glass sheet and polymethyl methacrylate.

[0011] In certain preferred embodiments, a three-step process is used to further reduce the interface between inorganic and organic materials. For example, a nanomaterial skeleton composed of glass sheets is first treated with a silane coupling agent to attach double bonds to the surface; then, it is placed in a precursor solution containing the monomer methyl methacrylate and the initiator azobisisobutyronitrile, and a short chain of polymethyl methacrylate is attached to the surface of the glass sheet; finally, the resulting skeleton material is placed in a new methyl methacrylate precursor solution, which is re-injected into the interlayer of the glass sheets, and then a polymerization reaction is initiated to achieve a chemical bond connection between the glass sheets and the polymethyl methacrylate.

[0012] When the refractive index of the resin needs to be adjusted, the dopant can be dispersed into the precursor solution.

[0013] The prepolymer resin of the present invention includes epoxy resin, acrylic resin, phenolic resin, urea-formaldehyde resin and the like; the high molecular monomer includes methyl methacrylate, styrene, acrylonitrile and the like.

[0014] The present invention utilizes gel-induced assembly of a two-dimensional nanomaterial framework, specifically as follows: two-dimensional rigid primitives and a gel component are dispersed in water to form an assembly solution; a substrate capable of releasing charged particles is placed in the assembly solution, and the two-dimensional rigid primitives are assembled along the surface of the substrate; the substrate and gel component are removed to obtain a nanomaterial framework composed of two-dimensional rigid primitives, the two-dimensional rigid primitives being oriented along the surface of the substrate; the two-dimensional rigid primitives can form an electrostatic interaction with the charged particles; and the gel component can form a gel under the induction of the charged particles. In the present invention, the gel component can form a gel under the induction of the charged particles, which synchronizes the diffusion of the charged particles with the formation of the gel. The large number of charged particles at the gel interface makes the interface electrically charged, continuously attracting nanosheets of opposite charge to migrate toward the interface. When the nanosheets are parallel to the gel surface, they have the maximum contact area and reach the most stable state, thus aligning the nanosheets parallel to the gel interface. Once the nanosheets are oriented at the gel interface, as the charged particles further diffuse, the nanosheets are fixed. The charged particles continue to diffuse forward perpendicular to the substrate, further orienting and fixing the subsequent nanosheets.

[0015] Experiments have shown that the volume fraction of two-dimensional rigid elements is below 20 vol%. If the content is too high, the steric hindrance between the nanosheets will be relatively large, affecting the turning of the nanosheets in space and reducing the degree of orientation.

[0016] Because assembly units are assembled by charged particles released from the substrate, those skilled in the art can foresee that the concentration of charged particles released from the substrate will affect the thickness of the aligned assembly. A higher concentration of charged particles results in a thicker assembly; experiments have shown that ordered assembly can be achieved at a concentration of 0.1 mol / L. Those skilled in the art can adjust the concentration of charged particles released from the substrate based on desired product thickness.

[0017] In the present invention, the content of the gel component is subject to the following prerequisites: ① The concentration cannot be too low, otherwise, gel formation cannot be achieved under the induction of the charged particles; ② The concentration cannot be too high, otherwise, the viscosity of the assembly solution is too high, resulting in orientation resistance. Generally, the viscosity of the assembly solution should be below 500 mPa·s. It is common knowledge in the art to formulate the required concentrations of the various assembly solution components based on these two prerequisites.

[0018] In addition, since the formation speed of the gel is directly related to the release speed of the charged particles of the substrate, it has been proved through experiments that when the formation speed of the gel is below 0.2 mm / min, the effective orientation induction of the gel for the assembly unit can be guaranteed. For example, for divalent calcium ions, under adsorption conditions, the concentration of the charged particles adsorbed by the substrate is set to below 5 mol / L, which can ensure that the speed of gel formation is below 0.2 mm / min; and for trivalent iron ions, under adsorption conditions, the concentration of the charged particles adsorbed by the substrate is set to below 1 mol / L to ensure that the speed of gel formation is below 0.2 mm / min. Those skilled in the art can regulate the concentration of the adsorbed charged particles by detecting the formation speed of the gel, or regulate the electrochemical reaction speed (such as the current size, for the metal that releases the charged particles in situ in the reaction), so as to achieve the best promoting effect of the gel.

[0019] In certain preferred embodiments of the present invention, the skeleton material is compressed and densified to obtain a dense skeleton. The resulting skeleton is uniaxially compressed at a pressure of 100 MPa to 400 MPa for a period of time to obtain a skeleton with a volume fraction of approximately 60 vol%. The composite material can be obtained by filling the resin in the same manner. The dense skeleton further improves the strength and modulus of the composite material.

[0020] In the present invention, the charged particles are selected from cations including: Na + , Ca 2+ 、Zn 2+ 、Ba 2+ 、Cu 2+ 、Fe 3+ 、Al 3+ 、Zr 4+ etc., but not limited to.

[0021] In the present invention, the gel component is selected from carboxyl polyelectrolytes: sodium alginate, pectin, cellulose, carboxyl PU, carboxylated chitosan, sodium polygalacturonate, etc., but is not limited thereto.

[0022] In the present invention, the substrate surface is a plane or a curved surface, or any other irregular shape.

[0023] In the present invention, the methods for removing the gel components include: physical high-temperature burning and chemical dissociation.

[0024] Compared with the prior art, the present invention has the following beneficial effects: light weight, high strength, high modulus, high toughness, high transparency, and can be produced in large areas and on a large scale. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is an optical image of the assembled calcium alginate hydrogel on a glass sheet with an oriented structure;

[0026] Figure 2 This is an optical image of the glass sheet calcium alginate composite material with an oriented structure after drying;

[0027] Figure 3 This is an SEM image of the cross section of a glass sheet calcium alginate composite material with an oriented structure;

[0028] Figure 4 This is an optical image of a glass flake polymethyl methacrylate composite transparent material with an oriented structure, wherein the volume fraction of the glass flake is about 20 vol%;

[0029] Figure 5 This is an optical image of a glass flake polymethyl methacrylate composite transparent material with an oriented structure, wherein the volume fraction of the glass flake is about 55 vol%;

[0030] Figure 6 This is an SEM image of the cross section of a disordered glass sheet calcium alginate composite material. DETAILED DESCRIPTION

[0031] In order to further illustrate the technical means and effects adopted by the present invention to achieve the predetermined purpose of the invention, the specific implementation methods, structures, features and effects of the present invention are described in detail below in conjunction with the accompanying drawings and preferred embodiments.

[0032] In the description of the present invention, it should be understood that the terms "plane", "xy plane", "front and back", "left and right", "vertical direction", "normal", "up and down", "upward", "downward", etc., indicating orientations or positional relationships, are orientations or positional relationships, which are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0033] Since the concentration of the assembly units, the viscosity of the assembly liquid, and the concentration of charged particles in the solution adsorbed on the substrate can all be adjusted according to needs through simple experiments, in the following embodiments, unless otherwise specified, the concentration of the assembly units is calculated to be 0-20 vol%, the viscosity of the assembly liquid is tested to be below 500 mPa·s, the concentration of charged particles adsorbed on the substrate is above 0.1 mol / L, and the gel speed is ensured to be below 0.2 mm / min.

[0034] Example 1:

[0035] (1) 95 g of a glass sheet (approximately 30 μm in diameter and 0.8 μm in thickness) and 125 g of a 2 wt% sodium alginate aqueous solution were added to 125 ml of water and stirred vigorously for 1 h. The volume fraction of the glass sheet was 12.5 vol%, the mass fraction of the sodium alginate was 0.5 wt%, and the viscosity of the assembly solution was below 500 mPa·s.

[0036] (2) Apply 1 mol / L calcium chloride solution to the surface of the filter paper to adsorb positive charges on the surface of the filter paper.

[0037] (3) Place the filter paper with positive charges adsorbed on the surface in the glass slide / sodium alginate dispersion and remove it after assembling for 5 minutes.

[0038] (4) The assembled material is separated from the filter paper, and its optical photograph is as follows Figure 1 As shown, and placed in a 60℃ oven and dried for 4 hours to obtain a glass sheet calcium alginate composite material with an oriented structure. The filling amount of glass sheets in the composite material is about 20vol%. The optical photograph is shown in FIG. Figure 2 As shown, its SEM photo is as Figure 3 shown.

[0039] (5) The dried glass sheet calcium alginate composite material is burned at 500° C. to remove the organic components, thereby obtaining a glass sheet skeleton material with an oriented structure.

[0040] (6) Add 50 ml of silane coupling agent methacryloxytrimethoxysilane to 50 ml of anhydrous ethanol and stir vigorously for 2 h.

[0041] (7) The skeleton material was placed in the solution obtained in (6) for 3 days, and the skeleton material was taken out from the solution and placed in an oven at 60° C. for drying for 3 hours to obtain a surface-modified skeleton material.

[0042] (8) 0.1 g of azobisisobutyronitrile and 2 g of phenanthrene were added to 9.4 g of methyl methacrylate and stirred vigorously for 10-30 min to obtain a precursor solution of methyl methacrylate.

[0043] (9) The skeleton material obtained in (7) is placed in a precursor solution of methyl methacrylate, heated in a water bath at 50°C for 30 min, a short chain of polymethyl methacrylate is attached to the surface of the skeleton, and then the skeleton material is removed from the precursor solution.

[0044] (10) The skeleton material obtained in (9) was placed in a new methyl methacrylate precursor solution, heated in a 50°C water bath for 3 days, then heated in a 70°C water bath for 3 days, and finally post-cured in a 90°C oven for 4 hours to obtain a light-weight, high-strength, transparent composite material. The filling amount of the glass sheet was about 20 vol%, and the optical photograph was as follows: Figure 4 shown.

[0045] (11) Optical characterization test

[0046] The obtained lightweight and high-strength composite material was tested for transmittance in the visible light band, and the average transmittance in the 400-760 nm band was 80%.

[0047] (12) Mechanical properties characterization test

[0048] The obtained lightweight and high-strength composite material was polished into strips about 1 mm thick and 20 mm long, and a three-point bending test was performed with a span of 16 mm. The bending strength was 180 MPa and the bending modulus was 14 GPa.

[0049] Example 2:

[0050] (1) 95 g of a glass sheet (approximately 30 μm in diameter and 0.8 μm in thickness) and 125 g of a 2 wt% sodium alginate aqueous solution were added to 125 ml of water and stirred vigorously for 1 h. The volume fraction of the glass sheet was 12.5 vol%, the mass fraction of the sodium alginate was 0.5 wt%, and the viscosity of the assembly solution was below 500 mPa·s.

[0051] (2) Dip-coat the surface of the filter paper with 0.5 mol / L calcium chloride solution to allow the surface of the filter paper to adsorb positive charges.

[0052] (3) Place the filter paper with positive charges adsorbed on the surface in the glass slide / sodium alginate dispersion and remove it after assembling for 5 minutes.

[0053] (4) The assembled material was separated from the filter paper and placed in an oven at 60°C for 2 hours to obtain a glass sheet calcium alginate composite material with an oriented structure. The filling amount of the glass sheet in the composite material was about 20 vol%.

[0054] (5) The dried glass sheet calcium alginate composite material is burned at 500° C. to remove the organic components, thereby obtaining a glass sheet skeleton material with an oriented structure.

[0055] (6) The skeleton material is placed in a mold and uniaxially compressed at 100 MPa at room temperature until the volume fraction of the glass sheet is approximately 55 vol%.

[0056] (7) Add 10 ml of silane coupling agent methacryloxytrimethoxysilane to 50 ml of anhydrous ethanol and stir vigorously for 2 h.

[0057] (8) The skeleton material was placed in the solution obtained in (7) for 3 days, and the skeleton material was taken out from the solution and placed in an oven at 60°C for drying for 2 hours to obtain a surface-modified skeleton material.

[0058] (9) 0.04 g of azobisisobutyronitrile and 2 g of phenanthrene were added to 9.4 g of methyl methacrylate and stirred vigorously for 10 min to obtain a precursor solution of methyl methacrylate.

[0059] (10) The skeleton material obtained in (8) is placed in a precursor solution of methyl methacrylate, heated in a water bath at 50°C for 30 min, a short chain of polymethyl methacrylate is attached to the surface of the skeleton, and then the skeleton material is removed from the precursor solution.

[0060] (11) The skeleton material obtained in (10) was placed in a new methyl methacrylate precursor solution, heated in a 50°C water bath for 1 day, then heated in a 70°C water bath for 1 day, and finally post-cured in a 90°C oven for 6 hours to obtain a light-weight, high-strength transparent composite material. The filling amount of the glass sheet was about 55 vol%, and the optical photograph is shown in FIG. Figure 5 shown.

[0061] (12) Optical characterization test

[0062] The light transmittance of the obtained lightweight and high-strength composite material was tested in the visible light band, and the average light transmittance in the 400-760 nm band was 60%.

[0063] (13) Mechanical properties characterization test

[0064] The obtained lightweight, high-strength composite material was polished into strips about 1 mm thick and 20 mm long, and a three-point bending test was performed with a span of 16 mm. The bending strength was 320 MPa and the bending modulus was 60 GPa.

[0065] Example 3:

[0066] (1) 95 g of glass flakes (approximately 30 μm in diameter and 0.8 μm in thickness) were added to 125 ml of water. Sodium alginate was then slowly added while the viscosity was monitored. When the viscosity of the assembly solution reached approximately 500 mPa·s, the addition was stopped, completing the preparation of the assembly solution. The volume fraction of the glass flakes was measured to be 12.5 vol%.

[0067] (2) Dip-coat the filter paper surface with 5 mol / L calcium chloride solution to allow the filter paper surface to adsorb positive charges.

[0068] (3) Place the filter paper with positive charges adsorbed on the surface in the glass slide / sodium alginate dispersion and remove it after assembling for 5 minutes.

[0069] (4) The assembled material was separated from the filter paper and placed in an oven at 60°C for 2 hours to obtain a glass sheet calcium alginate composite material with an oriented structure. The filling amount of the glass sheet in the composite material was about 20 vol%.

[0070] (5) The dried glass sheet calcium alginate composite material is burned at 500° C. to remove the organic components, thereby obtaining a glass sheet skeleton material with an oriented structure.

[0071] (6) The skeleton material is placed in a mold and uniaxially compressed at 400 MPa at room temperature until the volume fraction of the glass sheet is approximately 60 vol%.

[0072] (7) Add 2 g of silane coupling agent methacryloxytrimethoxysilane to 100 ml of anhydrous ethanol and stir vigorously for 2 h.

[0073] (8) The skeleton material was placed in the solution obtained in (7) for 2-3 days, and the skeleton material was taken out from the solution and placed in an oven at 60°C for drying for 2 hours to obtain a surface-modified skeleton material.

[0074] (9) 0.1 g of azobisisobutyronitrile and 2 g of phenanthrene were added to 9.4 g of methyl methacrylate and stirred vigorously for 10 min to obtain a precursor solution of methyl methacrylate.

[0075] (10) Place the skeleton material obtained in (8) in a precursor solution of methyl methacrylate, heat it in a water bath at 50°C for 30 minutes, attach a short chain of polymethyl methacrylate to the surface of the skeleton, and then remove the skeleton material from the precursor solution.

[0076] (11) The skeleton material obtained in (10) was placed in a new methyl methacrylate precursor solution, heated in a 50°C water bath for 1 day, then heated in a 70°C water bath for 3 days, and finally post-cured in a 90°C oven for 4 hours to obtain a lightweight, high-strength, transparent composite material. The glass flake filling amount was approximately 60 vol%.

[0077] (12) Optical characterization test

[0078] The obtained lightweight and high-strength composite material was tested for transmittance in the visible light band, and the average transmittance in the 400-760 nm band was 50%.

[0079] (13) Mechanical properties characterization test

[0080] The obtained lightweight, high-strength composite material was polished into strips about 1 mm thick and 20 mm long, and a three-point bending test was performed with a span of 16 mm. The bending strength was 200 MPa and the bending modulus was 40 GPa.

[0081] Comparative Example 1:

[0082] (1) Dissolve 2 g of glass flakes (diameter approximately 30 μm, thickness approximately 0.8 μm) in 10 g of water and stir vigorously for 1 h.

[0083] (2) The solution obtained in (1) was poured into a mold and allowed to stand for 24 hours. The supernatant was then poured off, the mold was removed, and the mold was placed in a 60°C oven and dried for 2 hours to obtain a glass sheet skeleton material with an irregular structure. The SEM photograph of the material is shown in FIG. Figure 6 shown.

[0084] (3) 0.04 g of azobisisobutyronitrile and 1 g of phenanthrene were added to 9.4 g of methyl methacrylate and stirred vigorously for 30 min to obtain a precursor solution of methyl methacrylate.

[0085] (4) The skeleton material obtained in (2) was placed in a methyl methacrylate precursor solution, heated in a 50°C water bath for 1 day, then heated in a 70°C water bath for 1 day, and finally post-cured in a 90°C oven for 4 hours to obtain a glass sheet polymethyl methacrylate composite material. The glass sheet filling amount was approximately 20 vol%.

[0086] (5) Optical characterization test

[0087] The obtained glass sheet polymethyl methacrylate composite material was tested for transmittance in the visible light band, and the average transmittance in the 400-760 nm band was 40%.

[0088] (6) Mechanical properties characterization test

[0089] The obtained glass sheet polymethyl methacrylate composite material was polished into a specimen with a thickness of about 1 mm and a length of about 20 mm. A three-point bending test was performed with a span of 16 mm. The bending strength was 100 MPa and the bending modulus was 7 GPa.

[0090] Comparative Example 2 - Two-step method:

[0091] (1) 95 g of a glass sheet (approximately 30 μm in diameter and 0.8 μm in thickness) and 125 g of a 2 wt% sodium alginate aqueous solution were added to 125 ml of water and stirred vigorously for 1 h. The volume fraction of the glass sheet was 12.5 vol%, the mass fraction of the sodium alginate was 0.5 wt%, and the viscosity of the assembly solution was below 500 mPa·s.

[0092] (2) Dip-coat the surface of the filter paper with a 2 mol / L calcium chloride solution to allow the surface of the filter paper to adsorb positive charges.

[0093] (3) Place the filter paper with positive charges adsorbed on the surface in the glass slide / sodium alginate dispersion and remove it after assembling for 5 minutes.

[0094] (4) The assembled material was separated from the filter paper and placed in an oven at 60°C for 4 hours to obtain a glass sheet calcium alginate composite material with an oriented structure. The filling amount of the glass sheet in the composite material was about 20 vol%.

[0095] (5) The dried glass sheet calcium alginate composite material is burned at 500° C. to remove the organic components, thereby obtaining a glass sheet skeleton material with an oriented structure.

[0096] (6) Add 5 ml of silane coupling agent methacryloxytrimethoxysilane to 100 ml of anhydrous ethanol and stir vigorously for 2 h.

[0097] (7) The skeleton material was placed in the solution obtained in (6) for 3 days, and the skeleton material was taken out from the solution and placed in an oven at 60° C. for drying for 3 hours to obtain a surface-modified skeleton material.

[0098] (8) 0.1 g of azobisisobutyronitrile and 2 g of phenanthrene were added to 9.4 g of methyl methacrylate and stirred vigorously for 10-30 min to obtain a precursor solution of methyl methacrylate.

[0099] (9) The skeleton material obtained in (7) was placed in the precursor solution obtained in (8), heated in a 50°C water bath for 3 days, then heated in a 70°C water bath for 3 days, and finally post-cured in a 90°C oven for 4 hours to obtain a lightweight, high-strength transparent composite material. The glass flake filling amount was approximately 20 vol%.

[0100] (10) Optical characterization test

[0101] The obtained lightweight and high-strength composite material was tested for transmittance in the visible light band, and the average transmittance in the 400-760 nm band was 70%.

[0102] (11) Mechanical properties characterization test

[0103] The obtained lightweight and high-strength composite material was polished into strips about 1 mm thick and 20 mm long, and a three-point bending test was performed with a span of 16 mm. The bending strength was 120 MPa and the bending modulus was 10 GPa.

[0104] Example 4

[0105] (1) 152 g of mica flakes (about 50 μm in diameter and 1 μm in thickness) and 125 g of a 2 wt% sodium alginate aqueous solution were added to 125 ml of water and stirred vigorously for 1 h. The volume fraction of the mica flakes was 20 vol%, the mass fraction of the sodium alginate was 0.5 wt%, and the viscosity of the assembly solution was below 500 mPa·s.

[0106] (2) Dip-coat the filter paper surface with 0.1 mol / L barium chloride solution to allow the filter paper surface to adsorb positive charges.

[0107] (3) Place the filter paper with positive charge adsorbed on the surface in the mica sheet / sodium alginate dispersion and remove it after assembling for 5 minutes.

[0108] (4) The assembled material was separated from the filter paper and placed in a 60°C oven for drying for 2 hours to obtain a mica sheet calcium alginate composite material with an oriented structure. The filling amount of the mica sheet in the composite material was about 20 vol%.

[0109] (5) The dried mica sheet calcium alginate composite material is burned at 500° C. to remove the organic components, thereby obtaining a mica sheet skeleton material with an oriented structure.

[0110] (6) The mica sheet skeleton with an oriented structure was surface-modified by silane coupling with KH-560, that is, it was immersed in a solution containing KH-560: ethanol: water = 1:95:5 mass ratio at 50°C for 24 hours to achieve interface modification.

[0111] (7) An epoxy resin (100 parts by weight of bisphenol F, 100 parts by weight of methylhexahydrophthalic anhydride, and 1 part by weight of 2,4,6-tris(dimethylaminomethyl)phenol) was vacuum-filled and cured at 100°C for 12 hours. A light, high-strength, transparent resin was obtained after curing.

[0112] (8) Optical characterization test

[0113] The obtained lightweight and high-strength composite material was tested for transmittance in the visible light band, and the average transmittance in the 400-760 nm band was 50%.

[0114] (9) Mechanical properties characterization test

[0115] The obtained lightweight and high-strength composite material was polished into strips about 1 mm thick and 20 mm long, and a three-point bending test was performed with a span of 16 mm. The bending strength was 180 MPa and the bending modulus was 14 GPa.

[0116] The above description is merely a preferred embodiment of the present invention and does not constitute any form of limitation to the present invention. Although the present invention has been disclosed as above in terms of a preferred embodiment, it is not intended to limit the present invention. Any person skilled in the art can, without departing from the scope of the technical solution of the present invention, make some changes or modifications to equivalent embodiments using the technical contents disclosed above. However, any brief modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. Lightweight, high-strength and transparent material, characterized by: The invention comprises a nanomaterial skeleton and a resin filled in the nanomaterial skeleton; the nanomaterial skeleton is composed of two-dimensional rigid elements, the surfaces of the two-dimensional rigid elements are connected to the resin through chemical bonds; the refractive index of the resin matches the refractive index of the rigid elements to achieve transparent optical properties; the rigid elements are glass nanosheets or mica nanosheets; The nanomaterial skeleton is prepared by the following method: dispersing two-dimensional rigid elements and gel components in water to form an assembly liquid, wherein the volume fraction of the two-dimensional rigid elements is less than 20 vol%; placing a substrate capable of releasing charged particles in the assembly liquid, and assembling the two-dimensional rigid elements along the surface of the substrate; removing the substrate and the gel components to obtain a nanomaterial skeleton composed of two-dimensional rigid elements, wherein the two-dimensional rigid elements are oriented along the surface of the substrate; wherein the two-dimensional rigid elements can form an electrostatic attraction with the charged particles; and the gel component can form a gel under the induction of the charged particles.

2. The lightweight, high-strength transparent material according to claim 1, characterized in that: The refractive index of the resin is adjusted by a dopant to match the refractive index of the rigid element so as to achieve transparent optical properties; the dopant is a small molecule organic substance containing electrons.

3. The lightweight, high-strength transparent material according to claim 2, characterized in that: The electron-containing small molecule organic dopant is phenanthrene or biphenyl.

4. The lightweight, high-strength transparent material according to claim 1, characterized in that: The resin is obtained by injecting a solution of a precursor into a skeleton and then polymerizing it; before injecting the precursor, the two-dimensional rigid elements of the skeleton are surface modified so that the two-dimensional rigid elements form a chemical bond connection with the resin; the precursor is a prepolymer resin or a high molecular monomer.

5. The lightweight, high-strength transparent material according to claim 4, characterized in that: The precursor solution contains a dopant, which is a small molecule organic substance containing electrons.

6. The lightweight, high-strength transparent material according to claim 4, characterized in that: The prepolymer resin includes epoxy resin, acrylic resin, phenolic resin and urea-formaldehyde resin; the high molecular monomer includes methyl methacrylate, styrene and acrylonitrile.

7. The lightweight, high-strength transparent material according to claim 1, characterized in that: The charged particles are selected from cations including: Na + , Ca 2+ 、Zn 2+ 、Ba 2+ 、Cu 2+ 、Fe 3+ 、Al 3+ 、Zr 4+ .

8. The lightweight, high-strength transparent material according to claim 1, characterized in that: The gel component is selected from carboxyl polyelectrolyte: sodium alginate, pectin, cellulose, carboxyl PU, carboxylated chitosan, sodium polygalacturonate.

9. The lightweight, high-strength transparent material according to claim 1, characterized in that: The substrate surface is a plane or a curved surface, or any other irregular shape.

10. The light-weight, high-strength transparent material according to claim 1, characterized in that: Methods for removing gel components include: physical high-temperature burning and chemical dissociation.

11. The light-weight, high-strength transparent material according to claim 1, characterized in that: The method also includes compressing and densifying the skeleton material to obtain a dense skeleton.

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