A high-strength, high-temperature-resistant and ultraviolet-resistant composite film imitating mussel structure and preparation method thereof

Abstract

The invention provides a high-strength, high-temperature-resistant and ultraviolet-resistant composite membrane with a mussel-like structure and a preparation method thereof. Basalt flakes are used as raw materials, and hydrochloric acid is used for preliminary surface etching. Then, strontium ions, tetrabutylammonium ions and cetylpyridinium ions are used for exchange with magnesium ions between basalt flakes to form a multi-layer structure of the basalt flakes. Then, ball milling is used to realize liquid-phase peeling of the basalt flakes, and finally basalt nanosheets are formed by shedding. After basalt nanosheets are doped into aramid nanofibers, vacuum self-assembly and filtration are performed to form a membrane to obtain a high-strength, high-temperature-resistant and ultraviolet-resistant composite membrane with a mussel-like structure. The invention adopts a simple, effective and easy-to-operate preparation method to prepare the high-strength / high-temperature-resistant / ultraviolet-resistant composite membrane with a mussel-like structure. The raw materials are low-cost, no large-scale equipment is required, and industrialization is relatively easy to achieve, thereby improving the possibility of industrialized mass production.

Description

Technical Field

[0001] The invention belongs to the field of polymer composite materials, and in particular relates to a high-strength, high-temperature-resistant and ultraviolet-resistant composite film with a mussel-like structure and a preparation method thereof. Background Art

[0002] Aramid nanofibers are prepared by dissolving and regenerating para-aramid fibers. Through intramolecular and intermolecular bonding, a highly transparent aramid nanofiber film can be obtained, which has excellent mechanical properties and thermal stability. Therefore, aramid nanofibers have broad application prospects in electromagnetic shielding materials, heat-resistant filter media, battery separators, flexible electrodes and biological tissues. However, due to its special chemical structure, the aramid nanofiber membrane has a low degree of heat resistance and UV resistance, which limits its application as a high-performance composite membrane in high-tech fields such as military, aerospace, and high-end insulation, where materials have high heat resistance and UV resistance.

[0003] In recent years, with the rapid development of the military industry and high-end manufacturing industry, the industry has been continuously transformed and upgraded, and high-performance composite membranes have gradually developed towards super-strong, super-tough, high and low temperature resistance, and UV resistance. The stability, safety and application environment of the composite membrane also put forward greater tests on its performance and environmental adaptability. In order to overcome the shortcomings of the above-mentioned aramid nanofiber composite membrane with low heat resistance temperature and weak UV shielding performance, the present invention provides an aramid nanofiber doped basalt nanosheet high temperature resistant / UV-resistant composite membrane and a preparation method thereof. Basalt flakes are a new type of flake material. They are a new type of material processed by special processes such as high-temperature melting, clarification, homogenization molding, and screening of natural basalt ore with excellent performance. They present a transparent or dark green flaky structure, with a thickness of generally about 3μm and a size of generally between 25μm and 3mm. Since the content of iron oxide, titanium dioxide, aluminum oxide, and calcium oxide in basalt flakes is high, and the content of alkaline oxides is low, the basalt flakes can not only produce a shielding effect, but also have unique advantages in high and low temperature resistance, acid and alkali resistance, and corrosion resistance. As an important member of high-performance fibers, aramid nanofibers have excellent properties such as high strength and modulus, good toughness, light weight, acid and alkali resistance, and excellent insulation properties. They can be used to produce composite membranes with high strength and rich functional groups by filtration. However, at present, there are few studies on high-temperature / UV-resistant composite membranes prepared by doping aramid nanofibers with basalt nanosheets in this field. It is urgent to find a method for preparing high-temperature / UV-resistant composite membranes doped with aramid nanofibers and basalt nanosheets to fill the current technical gap in the industry. Summary of the invention

[0004] In view of the problems existing in the prior art, the present invention provides a simple and feasible method for preparing a composite insulating film of aramid nanofiber doped with basalt nanosheets to fill the current technical gap in the industry. The present invention uses basalt flakes as raw materials, performs preliminary surface etching with hydrochloric acid, removes some metal oxides and impurities on its surface, and forms a rough structure on its surface, and then uses strontium ions, tetrabutylammonium ions, and hexadecylpyridinium ions to exchange with magnesium ions between basalt flakes, and finally causes the basalt flakes to expand in a direction perpendicular to the plane of the flakes, so that the basalt flakes form a multi-layer structure, and then the mechanical force generated by ball milling realizes the liquid phase peeling of the basalt flakes, and finally falls off to form basalt nanosheets. In addition, para-aramid short fibers are prepared into aramid nanofibers through a potassium hydroxide system, and finally a high-strength / high-temperature-resistant / ultraviolet-resistant composite film with a mussel-like structure is formed through vacuum self-assembly.

[0005] The present invention is achieved through the following technical solutions:

[0006] A method for preparing a high-strength, high-temperature-resistant and ultraviolet-resistant composite film imitating a mussel structure, characterized in that it comprises the following steps:

[0007] (1) Preparation of basalt nanosheets: placing basalt flakes in a hydrochloric acid solution, stirring at a set temperature to perform a surface etching reaction, and filtering and washing to neutrality after the reaction is completed to obtain a basalt flake with preliminary surface etching; placing the basalt flake with preliminary surface etching in a strontium chloride, tetrabutylammonium bromide, and cetylpyridinium bromide solution, performing an ion exchange reaction at a set temperature, and filtering and washing after the reaction is completed to obtain an ion-exchanged basalt flake; preparing the ion-exchanged basalt flakes into a mixed suspension, and then subjecting the mixed suspension to a ball milling machine treatment, allowing the mixed suspension to stand, taking out the upper turbid liquid, and drying the mixed suspension to obtain a basalt nanosheet A;

[0008] (2) Surface modification of basalt nanosheets: stirring the basalt nanosheets A and a mixture of hydrogen peroxide / ammonia / deionized water to react, modifying the surface of the basalt nanosheets A to obtain polyhydroxylated basalt nanosheets B;

[0009] (3) Preparation of aramid nanofibers: Potassium hydroxide and deionized water are mixed to obtain a potassium hydroxide solution, and then para-aramid chopped fibers are immersed in the potassium hydroxide solution. After that, a dimethyl sulfoxide solution is added and stirred to react at room temperature. After the reaction is completed, a mixture of ethanol and deionized water is added to carry out a protonation reduction reaction, and after repeated washing, aramid nanofibers are obtained.

[0010] (4) Preparation of insulating film: The polyhydroxy basalt nanosheets B and aramid nanofibers are ball-milled and then filtered to form a film, and then dried to obtain a high-strength / high-temperature-resistant / ultraviolet-resistant composite film with a mussel-like structure.

[0011] Preferably, the dosage ratio of basalt flakes to hydrochloric acid solution in step (1) is 0.4 g:30 mL, the hydrochloric acid concentration is 4 moL / L, the water bath reaction temperature is 80° C., and the reaction time is 24 h.

[0012] Preferably, the concentration of the strontium chloride solution in step (1) is 0.1 mol / L to 1 mol / L, the concentration of the tetrabutylammonium bromide solution is 0.5 mol / L to 2 mol / L, the concentration of the cetylpyridinium bromide solution is 0.5 mol / L to 2 mol / L, the dosage ratio of the basalt flakes for preliminary surface etching to the strontium chloride solution is 1.0 g: 50 mL to 200 mL; the dosage ratio of the basalt flakes for preliminary surface etching to the tetrabutylammonium bromide solution is 1.0 g: 20 mL to 100 mL; the dosage ratio of the basalt flakes for preliminary surface etching to the cetylpyridinium bromide solution is 1.0 g: 20 mL to 80 mL; the ion exchange reaction temperature is 80°C, the stirring rate is 1000 rpm, and the reaction time is 6 h.

[0013] Preferably, the mass ratio of the ion-exchanged basalt flakes to water in the mixed suspension in step (1) is 0.1 g: 20 mL to 50 mL. The dispersion and pulverization treatment in step (3) uses a ball mill, the ball milling mechanical treatment time is 0.2 h to 0.6 h, and the standing time is 24 h.

[0014] Preferably, the mass ratio of the basalt nanosheets A, hydrogen peroxide, ammonia water and deionized water mixed solution in step (2) is 0.2 to 1:1:1:20. The reaction temperature is room temperature.

[0015] Preferably, in the potassium hydroxide solution in the step (3), the ratio of potassium hydroxide to deionized water is 1.5 g:20 mL, and the ratio of the para-aramid chopped fibers to dimethyl sulfoxide is 1 g:500 mL; and in the protonation reduction reaction in the step (3), the ratio of ethanol to deionized water is 100 mL:100 mL.

[0016] Preferably, the amount of basalt nanosheets B added in step (4) is 0.1wt% to 5.0wt% of the solid content of the aramid nanofibers;

[0017] Preferably, the mixing methods in step (4) are magnetic stirring, mechanical stirring and ball milling respectively; the stirring rates of the magnetic stirring and mechanical stirring are 500 rpm to 1500 rpm, and the stirring time is 0.5 to 2 h; and the ball milling time is 10 min to 30 min.

[0018] A method for preparing a high-strength, high-temperature-resistant and ultraviolet-resistant composite film with a mussel-like structure is prepared by the above-mentioned preparation method.

[0019] Preferably, the tensile strength of the high-strength, high-temperature-resistant and UV-resistant composite film with the mussel-like structure is 162.8 MPa to 269.4 MPa.

[0020] Compared with the prior art, the present invention has the following beneficial technical effects:

[0021] The present invention provides a high-strength, high-temperature-resistant and ultraviolet-resistant composite membrane with a mussel-like structure and a preparation method thereof. Low-cost basalt flakes are used as raw materials, and preliminary surface etching is performed with hydrochloric acid to remove metal oxides and impurities on the surface, so that a rough structure is formed on the surface. Strontium ions, tetrabutylammonium ions, and hexadecylpyridinium ions are exchanged with magnesium ions between basalt flakes through ion reverse osmosis, and finally the basalt flakes expand in a direction perpendicular to the plane of the flakes, so that the basalt flakes form a multi-layer structure, and then the liquid phase peeling of the basalt flakes is achieved through the mechanical force generated by ball milling, and finally basalt nanosheets are formed; in addition, a chemical method is used to perform nano-processing on para-aramid chopped fibers to obtain aramid nanofibers. After that, basalt nanosheets are doped in the aramid nanofibers, and then vacuum self-assembly and filtration are performed to form a membrane to obtain a high-strength, high-temperature-resistant and ultraviolet-resistant composite membrane with a mussel-like structure. This invention can enrich the preparation system of basalt nanosheets, provide new ideas for the preparation of basalt nanosheets, and provide theoretical guidance for the mechanical enhancement of basalt nanomaterials. The high-strength / high-temperature-resistant / ultraviolet-resistant composite film with a mussel-like structure prepared by the present invention has excellent strength, high-temperature resistance and ultraviolet resistance, making it have strong development prospects in the fields of aerospace and military industry.

[0022] Furthermore, the present invention adopts a simple, effective and easy-to-operate preparation method to prepare a high-strength / high-temperature-resistant / ultraviolet-resistant composite film with a mussel-like structure. The raw materials are cheap, no large-scale equipment is required, and industrialization is relatively easy to achieve, thereby increasing the possibility of industrial mass production. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 The cross-sectional morphology diagrams of the composite films prepared in Examples 1, 2, 3, 7, 8, and 9; Figure (a) is Example 1, Figure (b) is Example 2, Figure (c) is Example 3, Figure (d) is Example 7, Figure (e) is Example 8, and Figure (f) is Example 9;

[0024] Figure 2 Surface morphology of the composite film prepared in Example 5, Figure (a) is a microscopic morphology at 500 nm; Figure (b) is a microscopic morphology at 200 nm. DETAILED DESCRIPTION

[0025] The present invention is further described in detail below in conjunction with specific embodiments, which are intended to explain the present invention rather than to limit it.

[0026] It should be noted that the following detailed descriptions are exemplary and are intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which the present invention belongs.

[0027] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprising" and / or "including" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0028] Because basalt nanosheets have many physical properties of basalt scales, such as stable high and low temperature resistance, and have a large specific surface area and fewer surface impurities. Most importantly, basalt nanosheets have a nanostructure, and can be stacked with aramid nanofibers to form a dense layered structure. Aramid nanofibers and basalt nanosheets are closely combined through van der Waals forces and hydrogen bonds to form a mussel-like structure, which further improves its strength and density. In addition, basalt nanosheets have excellent strength, wear resistance, and acid and alkali resistance, making the resulting composite membrane have great prospects.

[0029] The embodiments of the present invention are described in further detail below:

[0030] (1) Preparation of basalt nanosheets: Weigh a certain mass of basalt flakes and place them in a three-necked flask, add hydrochloric acid solution (HCl), and the ratio of basalt flakes to hydrochloric acid solution (HCl) is 0.4g:30mL, the concentration of hydrochloric acid solution is 4moL / L, and mechanical stirring is carried out in a water bath at 80℃ for 24h to carry out surface etching reaction. After the reaction is completed, filter and wash until neutral (pH test paper test), and obtain preliminary surface-etched basalt flakes by vacuum drying, oven drying and freeze drying. Then a certain mass of the initially surface-etched basalt flakes is weighed and placed in a three-necked flask, and a prepared strontium chloride solution with a concentration of 0.1 mol / L to 1 mol / L (0.5 mol / L to 2 mol / L tetrabutylammonium bromide solution or 0.5 mol / L to 2 mol / L cetylpyridinium bromide solution) is added thereto, and the amount ratio of the initially surface-etched basalt flakes to the strontium chloride solution is 1.0 g: 50 mL to 200 mL (the amount ratio of the initially surface-etched basalt flakes to the tetrabutylammonium bromide solution is 1.0 g: 50 mL to 200 mL or the amount ratio of the initially surface-etched basalt flakes to the cetylpyridinium bromide solution is 1.0 g: 20 mL to 80 mL); the reaction temperature is 80°C, the stirring rate is 1000 rpm, and the reaction time is 6 hours. After the reaction is completed, the mixture is filtered and washed to neutrality (pH test paper test), and ion-exchanged basalt flakes are obtained by vacuum drying, oven drying and freeze drying. A certain mass of ion-exchanged basalt flakes is placed in a plastic beaker, and a certain volume of water is added thereto. The mass ratio of ion-exchanged basalt flakes to water is 0.1g:20mL~50mL. The beaker with the sample is transferred to a ball mill, a certain number of grinding balls are added to the ball mill, the ball mill is turned on, the power is adjusted to 1000W to start the reaction, and the reaction time is 0.2h~0.6h. After the reaction is completed, the sample is taken out and placed in a glass bottle for standby use. After standing for 24h, the upper turbid liquid is taken out, and basalt nanosheets are obtained by vacuum drying, oven drying and freeze drying.

[0031] (2) Surface modification of basalt nanosheets: Weigh 1.0 g of the basalt nanosheets A prepared in step (1) and place them in a three-necked flask, then add hydrogen peroxide, ammonia water, and deionized water, with the mass ratio of the basalt nanosheets A, hydrogen peroxide, ammonia water, and deionized water mixed solution being 0.2 to 1:1:1:20. Stir and react at room temperature, and after the reaction is completed, wash with deionized water and ethanol several times and store for later use.

[0032] (3) Preparation of aramid nanofibers: 1.5 g of potassium hydroxide was dissolved in 20 mL of deionized water to prepare a potassium hydroxide solution. 1 g of para-aramid chopped fibers was immersed in the potassium hydroxide solution for 1 h. 500 mL of dimethyl sulfoxide was added thereto and stirred at room temperature for 12 h. After the reaction was completed, 200 mL of a mixture of deionized water and ethanol (the mass ratio of deionized water to ethanol was 1:1) was uniformly added for protonation reduction. The fibers were repeatedly washed with deionized water and anhydrous ethanol until no excess dimethyl sulfoxide remained. The aramid nanofibers were then placed in a 4°C refrigerator for later use.

[0033] (4) Preparation of insulating film: The basalt nanosheets B with polyhydroxy groups on the surface obtained in step (2) are mixed with the aramid nanofibers in step (3), wherein the amount of basalt nanosheets B added is 0.1wt% to 5.0wt% of the solid content of the aramid nanofibers, and the mixing method is magnetic stirring, mechanical stirring, and ball milling; the stirring rate of magnetic stirring and mechanical stirring is 500rpm to 1500rpm, and the stirring time is 0.5 to 2h; the ball milling time is 10min to 30min. After the reaction is completed, the film is filtered and dried to obtain a high-strength, high-temperature-resistant, and UV-resistant composite film with a mussel-like structure.

[0034] The present invention is further described in detail below in conjunction with embodiments:

[0035] Example 1

[0036] A high-strength, high-temperature-resistant and ultraviolet-resistant composite film imitating a mussel structure and a preparation method thereof, comprising the following steps:

[0037] (1) Preparation of basalt nanosheets: Weigh a certain mass of basalt flakes and place them in a three-necked flask, add hydrochloric acid solution (HCl) thereto, and the ratio of basalt flakes to hydrochloric acid solution (HCl) is 0.4g:30mL, the concentration of hydrochloric acid solution is 4mol / L, and mechanical stirring is carried out in a water bath at 80℃ for 24h for surface etching reaction. After the reaction is completed, filter and wash until neutral (pH test paper test), and obtain basalt flakes with preliminary surface etching by vacuum drying, oven drying and freeze drying. Then weigh a certain mass of basalt flakes with preliminary surface etching and place them in a three-necked flask, add a prepared strontium chloride solution with a concentration of 0.1mol / L, and the ratio of basalt flakes with preliminary surface etching to strontium chloride solution is 1.0g:50mL; the reaction temperature is 80℃, the stirring rate is 1000rpm, and the reaction time is 6h. After the reaction is completed, the mixture is filtered and washed to neutrality (pH test paper test), and ion-exchanged basalt flakes are obtained by vacuum drying, oven drying and freeze drying. A certain mass of ion-exchanged basalt flakes is placed in a plastic beaker, and a certain volume of water is added thereto. The mass ratio of ion-exchanged basalt flakes to water is 0.1g:50mL. The beaker with the sample is transferred to a ball mill, a certain number of grinding balls are added to the ball mill, the ball mill is turned on, the power is adjusted to 1000W to start the reaction, and the reaction time is 0.2h. After the reaction is completed, the sample is taken out and placed in a glass bottle for standby use. After standing for 24h, the upper turbid liquid is taken out and basalt nanosheets are obtained by vacuum drying.

[0038] (2) Surface modification of basalt nanosheets: Weigh 1.0 g of the basalt nanosheets A prepared in step (1) and place them in a three-necked flask, then add hydrogen peroxide, ammonia water, and deionized water, with the mass ratio of basalt nanosheets A, hydrogen peroxide, ammonia water, and deionized water mixed solution being 1:1:1:20. Stir and react at room temperature, and after the reaction is completed, wash with deionized water and ethanol several times and store for later use.

[0039] (3) Preparation of aramid nanofibers: 1.5 g of potassium hydroxide was dissolved in 20 mL of deionized water to prepare a potassium hydroxide solution. 1 g of para-aramid chopped fibers was immersed in the potassium hydroxide solution for 1 h. 500 mL of dimethyl sulfoxide was added thereto and stirred at room temperature for 12 h. After the reaction was completed, 200 mL of a mixture of deionized water and ethanol (the mass ratio of deionized water to ethanol was 1:1) was uniformly added for protonation reduction. The fibers were repeatedly washed with deionized water and anhydrous ethanol until no excess dimethyl sulfoxide remained. The aramid nanofibers were then placed in a 4°C refrigerator for later use.

[0040] (4) Preparation of insulating film: The basalt nanosheets B with polyhydroxy groups on the surface obtained in step (2) are mixed with the aramid nanofibers in step (3), wherein the amount of basalt nanosheets B added is 0.1wt% of the solid content of the aramid nanofibers, and the mixing method is magnetic stirring, the stirring rate is 500 rpm, and the stirring time is 0.5 h. After the reaction is completed, the film is filtered and dried to obtain a high-strength, high-temperature, and UV-resistant composite film with a mussel-like structure.

[0041] Figure 1 a is a SEM image of the cross section of the composite membrane in step (1), Figure 1 It can be found that the composite film presents a mussel-like structure, but there is still agglomeration. As shown in Table 1, after the above-prepared nanosheets are added to the aramid nanofiber solution to prepare a composite film, the ultraviolet transmittance of the composite film is lower than that of the pure ANF film, the tensile strength at room temperature is 164.52MPa, and the tensile strength when heated to 400°C is 132.54MPa, and the strength reduction rate is 19.44%, which is lower than the strength reduction rate of the pure ANF film (51.19%).

[0042] Example 2

[0043] A high-strength, high-temperature-resistant and ultraviolet-resistant composite film imitating a mussel structure and a preparation method thereof, comprising the following steps:

[0044] (1) Preparation of basalt nanosheets: Weigh a certain mass of basalt flakes and place them in a three-necked flask, add hydrochloric acid solution (HCl) thereto, and the ratio of basalt flakes to hydrochloric acid solution (HCl) is 0.4g:30mL, the concentration of hydrochloric acid solution is 4mol / L, and the surface etching reaction is carried out by mechanical stirring for 24h in a water bath at 80℃. After the reaction is completed, filter and wash until neutral (pH test paper test), and obtain the basalt flakes with preliminary surface etching by vacuum drying, oven drying and freeze drying. Then weigh a certain mass of the basalt flakes with preliminary surface etching and place them in a three-necked flask, add the prepared strontium chloride solution with a concentration of 0.5mol / L, and the ratio of the basalt flakes with preliminary surface etching to the strontium chloride solution is 1.0g:100mL; the reaction temperature is 80℃, the stirring rate is 1000rpm, and the reaction time is 6h. After the reaction is completed, the mixture is filtered and washed to neutrality (pH test paper test), and ion-exchanged basalt flakes are obtained by vacuum drying, oven drying and freeze drying. A certain mass of ion-exchanged basalt flakes is placed in a plastic beaker, and a certain volume of water is added thereto. The mass ratio of ion-exchanged basalt flakes to water is 0.1g:30mL. The beaker with the sample is transferred to a ball mill, a certain number of grinding balls are added to the ball mill, the ball mill is turned on, the power is adjusted to 1000W to start the reaction, and the reaction time is 0.4h. After the reaction is completed, the sample is taken out and placed in a glass bottle for standby use. After standing for 24h, the upper turbid liquid is taken out and basalt nanosheets are obtained by oven drying.

[0045] (2) Surface modification of basalt nanosheets: Weigh 1.0 g of the basalt nanosheets A prepared in step (1) and place them in a three-necked flask, then add hydrogen peroxide, ammonia water, and deionized water, the mass ratio of the basalt nanosheets A, hydrogen peroxide, ammonia water, and deionized water mixture being 0.5:1:1:20. Stir and react at room temperature, and after the reaction is completed, wash with deionized water and ethanol several times and store for later use.

[0046] (3) Preparation of aramid nanofibers: 1.5 g of potassium hydroxide was dissolved in 20 mL of deionized water to prepare a potassium hydroxide solution. 1 g of para-aramid chopped fibers was immersed in the potassium hydroxide solution for 1 h. 500 mL of dimethyl sulfoxide was added thereto and stirred at room temperature for 12 h. After the reaction was completed, 200 mL of a mixture of deionized water and ethanol (the mass ratio of deionized water to ethanol was 1:1) was uniformly added for protonation reduction. The fibers were repeatedly washed with deionized water and anhydrous ethanol until no excess dimethyl sulfoxide remained. The aramid nanofibers were then placed in a 4°C refrigerator for later use.

[0047] (4) Preparation of insulating film: The basalt nanosheets B with polyhydroxy groups on the surface obtained in step (2) are mixed with the aramid nanofibers in step (3), wherein the amount of basalt nanosheets B added is 0.5 wt% of the solid content of the aramid nanofibers, and the mixing method is ball milling; the ball milling time is 30 min. After the reaction is completed, the film is filtered and dried to obtain a high-strength, high-temperature, and UV-resistant composite film with a mussel-like structure.

[0048] Figure 1 b is the SEM image of the cross section of the composite membrane in step (1), Figure 1 b It can be found that the composite membrane has an obvious mussel-like structure. As shown in Table 1, after the above-prepared nanosheets are added to the aramid nanofiber solution to prepare the composite membrane, the ultraviolet transmittance of the composite membrane is further reduced to 0.65, the tensile strength at room temperature is 189.78MPa, and the tensile strength when heated to 400°C is 161.55MPa, and the strength reduction rate is 14.88%, which is lower than the strength reduction rate of the pure ANF membrane (51.19%).

[0049] Example 3

[0050] A high-strength, high-temperature-resistant and ultraviolet-resistant composite film imitating a mussel structure and a preparation method thereof, comprising the following steps:

[0051] (1) Preparation of basalt nanosheets: Weigh a certain mass of basalt flakes and place them in a three-necked flask, add hydrochloric acid solution (HCl) thereto, and the ratio of basalt flakes to hydrochloric acid solution (HCl) is 0.4g:30mL, the concentration of hydrochloric acid solution is 4moL / L, and mechanical stirring is carried out for 24h in a water bath at 80℃ for surface etching reaction. After the reaction is completed, filter and wash until neutral (pH test paper test), and obtain basalt flakes with preliminary surface etching by vacuum drying, oven drying and freeze drying. Then weigh a certain mass of basalt flakes with preliminary surface etching and place them in a three-necked flask, add a prepared strontium chloride solution with a concentration of 1mol / L, and the ratio of basalt flakes with preliminary surface etching to strontium chloride solution is 1.0g:200mL; the reaction temperature is 80℃, the stirring rate is 1000rpm, and the reaction time is 6h. After the reaction is completed, the mixture is filtered and washed to neutrality (pH test paper test), and ion-exchanged basalt flakes are obtained by vacuum drying. A certain mass of ion-exchanged basalt flakes is placed in a plastic beaker, and a certain volume of water is added thereto. The mass ratio of ion-exchanged basalt flakes to water is 0.1g:20mL. The beaker with the sample is transferred to a ball mill, a certain number of grinding balls are added to the ball mill, the ball mill is turned on, the power is adjusted to 1000W to start the reaction, and the reaction time is 0.6h. After the reaction is completed, the sample is taken out and placed in a glass bottle for standby use. After standing for 24h, the upper turbid liquid is taken out and basalt nanosheets are obtained by freeze drying.

[0052] (2) Surface modification of basalt nanosheets: Weigh 1.0 g of the basalt nanosheets A prepared in step (1) and place them in a three-necked flask, then add hydrogen peroxide, ammonia water, and deionized water, with the mass ratio of basalt nanosheets A, hydrogen peroxide, ammonia water, and deionized water mixed solution being 0.2:1:1:20. Stir and react at room temperature, and after the reaction is completed, wash with deionized water and ethanol several times and store for later use.

[0053] (3) Preparation of aramid nanofibers: 1.5 g of potassium hydroxide was dissolved in 20 mL of deionized water to prepare a potassium hydroxide solution. 1 g of para-aramid chopped fibers was immersed in the potassium hydroxide solution for 1 h. 500 mL of dimethyl sulfoxide was added thereto and stirred at room temperature for 12 h. After the reaction was completed, 200 mL of a mixture of deionized water and ethanol (the mass ratio of deionized water to ethanol was 1:1) was uniformly added for protonation reduction. The fibers were repeatedly washed with deionized water and anhydrous ethanol until no excess dimethyl sulfoxide remained. The aramid nanofibers were then placed in a 4°C refrigerator for later use.

[0054] (4) Preparation of insulating film: The basalt nanosheets B with polyhydroxy groups on the surface obtained in step (2) are mixed with the aramid nanofibers in step (3), wherein the amount of basalt nanosheets B added is 1.0wt% of the solid content of the aramid nanofibers, and the mixing method is ball milling; the ball milling time is 30 min. After the reaction is completed, the film is filtered and dried to obtain a high-strength, high-temperature, and UV-resistant composite film with a mussel-like structure.

[0055] Figure 1 c is the SEM image of the cross section of the composite membrane in step (1), Figure 1 c It can be found that the composite membrane has a very obvious mussel-like structure and a clear layered structure. As shown in Table 1, after the above-prepared nanosheets are added to the aramid nanofiber solution to prepare a composite membrane, the ultraviolet transmittance of the composite membrane is further reduced to 0.21, the tensile strength at room temperature is 254.92MPa, and the tensile strength when heated to 400°C is 240.98MPa, and the strength reduction rate is 5.47%, which is lower than the strength reduction rate of the pure ANF membrane (51.19%).

[0056] Example 4

[0057] A high-strength, high-temperature-resistant and ultraviolet-resistant composite film imitating a mussel structure and a preparation method thereof, comprising the following steps:

[0058] (1) Preparation of basalt nanosheets: Weigh a certain mass of basalt flakes and place them in a three-necked flask, add hydrochloric acid solution (HCl) thereto, and the ratio of basalt flakes to hydrochloric acid solution (HCl) is 0.4g:30mL, the concentration of hydrochloric acid solution is 4mol / L, and mechanical stirring is carried out for 24h in a water bath at 80℃ for surface etching reaction. After the reaction is completed, filter and wash until neutral (pH test paper test), and obtain basalt flakes with preliminary surface etching by vacuum drying, oven drying and freeze drying. Then weigh a certain mass of basalt flakes with preliminary surface etching and place them in a three-necked flask, add tetrabutylammonium bromide solution with a concentration of 0.5mol / L, and the ratio of basalt flakes with preliminary surface etching to tetrabutylammonium bromide solution is 1.0g:50mL; the reaction temperature is 80℃, the stirring rate is 1000rpm, and the reaction time is 6h. After the reaction is completed, the mixture is filtered and washed to neutrality (pH test paper test), and then dried in an oven to obtain ion-exchanged basalt flakes. A certain mass of ion-exchanged basalt flakes is placed in a plastic beaker, and a certain volume of water is added thereto. The mass ratio of ion-exchanged basalt flakes to water is 0.1g:50mL. The beaker with the sample is transferred to a ball mill, a certain number of grinding balls are added to the ball mill, the ball mill is turned on, the power is adjusted to 1000W to start the reaction, and the reaction time is 0.2h. After the reaction is completed, the sample is taken out and placed in a glass bottle for standby use. After standing for 24h, the upper turbid liquid is taken out and basalt nanosheets are obtained by vacuum drying.

[0059] (2) Surface modification of basalt nanosheets: Weigh 1.0 g of the basalt nanosheets A prepared in step (1) and place them in a three-necked flask, then add hydrogen peroxide, ammonia water, and deionized water, with the mass ratio of basalt nanosheets A, hydrogen peroxide, ammonia water, and deionized water mixed solution being 1:1:1:20. Stir and react at room temperature, and after the reaction is completed, wash with deionized water and ethanol several times and store for later use.

[0060] (3) Preparation of aramid nanofibers: 1.5 g of potassium hydroxide was dissolved in 20 mL of deionized water to prepare a potassium hydroxide solution. 1 g of para-aramid chopped fibers was immersed in the potassium hydroxide solution for 1 h. 500 mL of dimethyl sulfoxide was added thereto and stirred at room temperature for 12 h. After the reaction was completed, 200 mL of a mixture of deionized water and ethanol (the mass ratio of deionized water to ethanol was 1:1) was uniformly added for protonation reduction. The fibers were repeatedly washed with deionized water and anhydrous ethanol until no excess dimethyl sulfoxide remained. The aramid nanofibers were then placed in a 4°C refrigerator for later use.

[0061] (4) Preparation of insulating film: The basalt nanosheets B with polyhydroxy groups on the surface obtained in step (2) are mixed with the aramid nanofibers in step (3), wherein the amount of basalt nanosheets B added is 0.5wt% of the solid content of the aramid nanofibers, and the mixing method is mechanical stirring at a stirring rate of 1000 rpm for 2 hours. After the reaction is completed, the film is filtered and dried to obtain a high-strength, high-temperature-resistant and UV-resistant composite film with a mussel-like structure.

[0062] It can be seen from Table 1 that after the prepared nanosheets are added to the aramid nanofiber solution to prepare a composite membrane, the UV transmittance of the composite membrane is further reduced to 0.79, the tensile strength is 173.63 MPa at room temperature, and the tensile strength is 145.38 MPa when heated to 400°C, with a strength reduction rate of 16.27%, which is mainly because the amount of nanosheets added is reduced and no obvious mussel-like structure is formed.

[0063] Example 5

[0064] A high-strength, high-temperature-resistant and ultraviolet-resistant composite film imitating a mussel structure and a preparation method thereof, comprising the following steps:

[0065] (1) Preparation of basalt nanosheets: Weigh a certain mass of basalt flakes and place them in a three-necked flask, add hydrochloric acid solution (HCl) thereto, and the ratio of basalt flakes to hydrochloric acid solution (HCl) is 0.4g:30mL, the concentration of hydrochloric acid solution is 4mol / L, and mechanical stirring is carried out for 24h in a water bath at 80℃ for surface etching reaction. After the reaction is completed, filter and wash until neutral (pH test paper test), and obtain basalt flakes with preliminary surface etching by vacuum drying, oven drying and freeze drying. Then weigh a certain mass of basalt flakes with preliminary surface etching and place them in a three-necked flask, add tetrabutylammonium bromide solution with a concentration of 1.0mol / L, and the ratio of basalt flakes with preliminary surface etching to tetrabutylammonium bromide solution is 1.0g:100mL; the reaction temperature is 80℃, the stirring rate is 1000rpm, and the reaction time is 6h. After the reaction is completed, the mixture is filtered and washed to neutrality (pH test paper test), and ion-exchanged basalt flakes are obtained by vacuum drying, oven drying and freeze drying. A certain mass of ion-exchanged basalt flakes is placed in a plastic beaker, and a certain volume of water is added thereto. The mass ratio of ion-exchanged basalt flakes to water is 0.1g:30mL. The beaker with the sample is transferred to a ball mill, a certain number of grinding balls are added to the ball mill, the ball mill is turned on, the power is adjusted to 1000W to start the reaction, and the reaction time is 0.4h. After the reaction is completed, the sample is taken out and placed in a glass bottle for standby use. After standing for 24h, the upper turbid liquid is taken out and basalt nanosheets are obtained by freeze drying.

[0066] (2) Surface modification of basalt nanosheets: Weigh 1.0 g of the basalt nanosheets A prepared in step (1) and place them in a three-necked flask, then add hydrogen peroxide, ammonia water, and deionized water, the mass ratio of the basalt nanosheets A, hydrogen peroxide, ammonia water, and deionized water mixture being 0.5:1:1:20. Stir and react at room temperature, and after the reaction is completed, wash with deionized water and ethanol several times and store for later use.

[0067] (3) Preparation of aramid nanofibers: 1.5 g of potassium hydroxide was dissolved in 20 mL of deionized water to prepare a potassium hydroxide solution. 1 g of para-aramid chopped fibers was immersed in the potassium hydroxide solution for 1 h. 500 mL of dimethyl sulfoxide was added thereto and stirred at room temperature for 12 h. After the reaction was completed, 200 mL of a mixture of deionized water and ethanol (the mass ratio of deionized water to ethanol was 1:1) was uniformly added for protonation reduction. The fibers were repeatedly washed with deionized water and anhydrous ethanol until no excess dimethyl sulfoxide remained. The aramid nanofibers were then placed in a 4°C refrigerator for later use.

[0068] (4) Preparation of insulating film: The basalt nanosheets B with polyhydroxy groups on the surface obtained in step (2) are mixed with the aramid nanofibers in step (3), wherein the amount of basalt nanosheets B added is 1.0 wt% of the solid content of the aramid nanofibers, and the mixing method is ball milling; the ball milling time is 15 min. After the reaction is completed, the film is filtered and dried to obtain a high-strength, high-temperature, and UV-resistant composite film with a mussel-like structure.

[0069] Figure 2 is the SEM image of the composite membrane plane. Figure 2 a It can be seen that the basalt nanosheets and aramid nanofibers are well combined, and the aramid nanofibers are wrapped on the surface of the basalt nanosheets; Figure 2 b shows that the basalt nanosheets are firmly fixed by the aramid nanofibers and are tightly bonded. As shown in Table 1, after the above-prepared nanosheets are added to the aramid nanofiber solution to prepare the composite membrane, the UV transmittance of the composite membrane is further reduced to 0.19, the tensile strength at room temperature is 261.31MPa, and the tensile strength when heated to 400°C is 245.63MPa, and the strength reduction rate is 6.00%, which is mainly due to the increase in the amount of nanosheets added, forming an obvious mussel-like structure, and the bonding strength between the nanosheets and nanofibers is relatively high.

[0070] Example 6

[0071] A high-strength, high-temperature-resistant and ultraviolet-resistant composite film imitating a mussel structure and a preparation method thereof, comprising the following steps:

[0072] (1) Preparation of basalt nanosheets: Weigh a certain mass of basalt flakes and place them in a three-necked flask, add hydrochloric acid solution (HCl) thereto, and the ratio of basalt flakes to hydrochloric acid solution (HCl) is 0.4g:30mL, the concentration of hydrochloric acid solution is 4mol / L, and mechanical stirring is carried out for 24h in a water bath at 80℃ for surface etching reaction. After the reaction is completed, filter and wash until neutral (pH test paper test), and obtain basalt flakes with preliminary surface etching by vacuum drying, oven drying and freeze drying. Then weigh a certain mass of basalt flakes with preliminary surface etching and place them in a three-necked flask, add tetrabutylammonium bromide solution with a concentration of 2mol / L, and the ratio of basalt flakes with preliminary surface etching to tetrabutylammonium bromide solution is 1.0g:200mL; the reaction temperature is 80℃, the stirring rate is 1000rpm, and the reaction time is 6h. After the reaction is completed, the mixture is filtered and washed to neutrality (pH test paper test), and ion-exchanged basalt flakes are obtained by vacuum drying, oven drying and freeze drying. A certain mass of ion-exchanged basalt flakes is placed in a plastic beaker, and a certain volume of water is added thereto. The mass ratio of ion-exchanged basalt flakes to water is 0.1g:50mL. The beaker with the sample is transferred to a ball mill, a certain number of grinding balls are added to the ball mill, the ball mill is turned on, the power is adjusted to 1000W to start the reaction, and the reaction time is 0.6h. After the reaction is completed, the sample is taken out and placed in a glass bottle for standby use. After standing for 24h, the upper turbid liquid is taken out and basalt nanosheets are obtained by freeze drying.

[0073] (2) Surface modification of basalt nanosheets: Weigh 1.0 g of the basalt nanosheets A prepared in step (1) and place them in a three-necked flask, then add hydrogen peroxide, ammonia water, and deionized water, with the mass ratio of basalt nanosheets A, hydrogen peroxide, ammonia water, and deionized water mixed solution being 0.2:1:1:20. Stir and react at room temperature, and after the reaction is completed, wash with deionized water and ethanol several times and store for later use.

[0074] (3) Preparation of aramid nanofibers: 1.5 g of potassium hydroxide was dissolved in 20 mL of deionized water to prepare a potassium hydroxide solution. 1 g of para-aramid chopped fibers was immersed in the potassium hydroxide solution for 1 h. 500 mL of dimethyl sulfoxide was added thereto and stirred at room temperature for 12 h. After the reaction was completed, 200 mL of a mixture of deionized water and ethanol (the mass ratio of deionized water to ethanol was 1:1) was uniformly added for protonation reduction. The fibers were repeatedly washed with deionized water and anhydrous ethanol until no excess dimethyl sulfoxide remained. The aramid nanofibers were then placed in a 4°C refrigerator for later use.

[0075] (4) Preparation of insulating film: The basalt nanosheets B with polyhydroxy groups on the surface obtained in step (2) are mixed with the aramid nanofibers in step (3), wherein the amount of basalt nanosheets B added is 5.0 wt% of the solid content of the aramid nanofibers, and the mixing method is ball milling; the ball milling time is 30 min. After the reaction is completed, the film is filtered and dried to obtain a high-strength, high-temperature, and UV-resistant composite film with a mussel-like structure.

[0076] It can be seen from Table 1 that after the prepared nanosheets are added to the aramid nanofiber solution to obtain a composite membrane, the UV transmittance of the composite membrane is further reduced to 0.05, the tensile strength at room temperature is 261.31 MPa, and the tensile strength when heated to 400°C is 133.15 MPa, with a strength reduction rate of 7.23%. This is mainly because the amount of nanosheets added is increased, forming an obvious mussel-like structure, and the bonding strength between the nanosheets and nanofibers is relatively high.

[0077] Example 7

[0078] A high-strength, high-temperature-resistant and ultraviolet-resistant composite film imitating a mussel structure and a preparation method thereof, comprising the following steps:

[0079] (1) Preparation of basalt nanosheets: Weigh a certain mass of basalt flakes and place them in a three-necked flask, add hydrochloric acid solution (HCl) thereto, and the ratio of basalt flakes to hydrochloric acid solution (HCl) is 0.4g:30mL, the concentration of hydrochloric acid solution is 4mol / L, and mechanical stirring is carried out in a water bath at 80℃ for 24h for surface etching reaction. After the reaction is completed, filter and wash until neutral (pH test paper test), and obtain basalt flakes with preliminary surface etching by vacuum drying, oven drying and freeze drying. Then weigh a certain mass of basalt flakes with preliminary surface etching and place them in a three-necked flask, add the prepared 0.5mol / L cetylpyridinium bromide solution thereto, and the ratio of basalt flakes with preliminary surface etching to cetylpyridinium bromide solution is 1.0g:20mL; the reaction temperature is 80℃, the stirring rate is 1000rpm, and the reaction time is 6h. After the reaction is completed, the mixture is filtered and washed to neutrality (pH test paper test), and ion-exchanged basalt flakes are obtained by vacuum drying, oven drying and freeze drying. A certain mass of ion-exchanged basalt flakes is placed in a plastic beaker, and a certain volume of water is added thereto. The mass ratio of ion-exchanged basalt flakes to water is 0.1g:50mL. The beaker with the sample is transferred to a ball mill, a certain number of grinding balls are added to the ball mill, the ball mill is turned on, the power is adjusted to 1000W to start the reaction, and the reaction time is 0.2h. After the reaction is completed, the sample is taken out and placed in a glass bottle for standby use. After standing for 24h, the upper turbid liquid is taken out and basalt nanosheets are obtained by vacuum drying.

[0080] (2) Surface modification of basalt nanosheets: Weigh 1.0 g of the basalt nanosheets A prepared in step (1) and place them in a three-necked flask, then add hydrogen peroxide, ammonia water, and deionized water, with the mass ratio of basalt nanosheets A, hydrogen peroxide, ammonia water, and deionized water mixed solution being 1:1:1:20. Stir and react at room temperature, and after the reaction is completed, wash with deionized water and ethanol several times and store for later use.

[0081] (3) Preparation of aramid nanofibers: 1.5 g of potassium hydroxide was dissolved in 20 mL of deionized water to prepare a potassium hydroxide solution. 1 g of para-aramid chopped fibers was immersed in the potassium hydroxide solution for 1 h. 500 mL of dimethyl sulfoxide was added thereto and stirred at room temperature for 12 h. After the reaction was completed, 200 mL of a mixture of deionized water and ethanol (the mass ratio of deionized water to ethanol was 1:1) was uniformly added for protonation reduction. The fibers were repeatedly washed with deionized water and anhydrous ethanol until no excess dimethyl sulfoxide remained. The aramid nanofibers were then placed in a 4°C refrigerator for later use.

[0082] (4) Preparation of insulating film: The basalt nanosheets B with polyhydroxy groups on the surface obtained in step (2) are mixed with the aramid nanofibers in step (3), wherein the amount of basalt nanosheets B added is 1.0wt% of the solid content of the aramid nanofibers, and the mixing method is magnetic stirring, the stirring rate is 500 rpm, and the stirring time is 0.5 h. After the reaction is completed, the film is filtered and dried to obtain a high-strength, high-temperature, and UV-resistant composite film with a mussel-like structure.

[0083] Figure 1 d is the SEM image of the cross section of the composite membrane in step (1), Figure 1 d, it can be found that the composite membrane has an obvious mussel-like structure. As shown in Table 1, after the above-prepared nanosheets are added to the aramid nanofiber solution to prepare the composite membrane, the UV transmittance of the composite membrane is further reduced to 0.22, the tensile strength at room temperature is 259.74MPa, and the tensile strength when heated to 400°C is 241.63MPa, and the strength reduction rate is 6.97%. This is mainly because the amount of nanosheets added is increased, forming an obvious mussel-like structure, and the bonding strength between nanosheets and nanofibers is relatively high.

[0084] Example 8

[0085] A high-strength, high-temperature-resistant and ultraviolet-resistant composite film imitating a mussel structure and a preparation method thereof, comprising the following steps:

[0086] (1) Preparation of basalt nanosheets: Weigh a certain mass of basalt flakes and place them in a three-necked flask, add hydrochloric acid solution (HCl) thereto, and the ratio of basalt flakes to hydrochloric acid solution (HCl) is 0.4g:30mL, the concentration of hydrochloric acid solution is 4moL / L, and mechanical stirring is carried out for 24h in a water bath at 80℃ for surface etching reaction. After the reaction is completed, filter and wash until neutral (pH test paper test), and obtain basalt flakes with preliminary surface etching by vacuum drying, oven drying and freeze drying. Then weigh a certain mass of basalt flakes with preliminary surface etching and place them in a three-necked flask, add the prepared 1.0 concentration of hexadecylpyridinium bromide solution thereto, and the ratio of the preliminary surface etching basalt flakes to the hexadecylpyridinium bromide solution is 1.0g:50mL; the reaction temperature is 80℃, the stirring rate is 1000rpm, and the reaction time is 6h. After the reaction is completed, the mixture is filtered and washed to neutrality (pH test paper test), and then dried in an oven to obtain ion-exchanged basalt flakes. A certain mass of ion-exchanged basalt flakes is placed in a plastic beaker, and a certain volume of water is added thereto. The mass ratio of ion-exchanged basalt flakes to water is 0.1g:30mL. The beaker with the sample is transferred to a ball mill, a certain number of grinding balls are added to the ball mill, the ball mill is turned on, the power is adjusted to 1000W to start the reaction, and the reaction time is 0.4h. After the reaction is completed, the sample is taken out and placed in a glass bottle for standby use. After standing for 24h, the upper turbid liquid is taken out and basalt nanosheets are obtained by oven drying.

[0087] (2) Surface modification of basalt nanosheets: Weigh 1.0 g of the basalt nanosheets A prepared in step (1) and place them in a three-necked flask, then add hydrogen peroxide, ammonia water, and deionized water, the mass ratio of the basalt nanosheets A, hydrogen peroxide, ammonia water, and deionized water mixture being 0.5:1:1:20. Stir and react at room temperature, and after the reaction is completed, wash with deionized water and ethanol several times and store for later use.

[0088] (3) Preparation of aramid nanofibers: 1.5 g of potassium hydroxide was dissolved in 20 mL of deionized water to prepare a potassium hydroxide solution. 1 g of para-aramid chopped fibers was immersed in the potassium hydroxide solution for 1 h. 500 mL of dimethyl sulfoxide was added thereto and stirred at room temperature for 12 h. After the reaction was completed, 200 mL of a mixture of deionized water and ethanol (the mass ratio of deionized water to ethanol was 1:1) was uniformly added for protonation reduction. The fibers were repeatedly washed with deionized water and anhydrous ethanol until no excess dimethyl sulfoxide remained. The aramid nanofibers were then placed in a 4°C refrigerator for later use.

[0089] (4) Preparation of insulating film: The basalt nanosheets B with polyhydroxy groups on the surface obtained in step (2) are mixed with the aramid nanofibers in step (3), wherein the amount of basalt nanosheets B added is 3.0 wt% of the solid content of the aramid nanofibers, and the mixing method is ball milling for 20 min. After the reaction is completed, the film is filtered and dried to obtain a high-strength, high-temperature, and UV-resistant composite film with a mussel-like structure.

[0090] Figure 1 e is a SEM image of the cross section of the composite membrane in step (1), Figure 1 e It can be found that the composite membrane has a more obvious mussel-like structure, and a layered structure can be seen. As shown in Table 1, after the above-prepared nanosheets are added to the aramid nanofiber solution to prepare a composite membrane, the ultraviolet transmittance of the composite membrane is further reduced to 0.22, the tensile strength at room temperature is 259.74MPa, and the tensile strength when heated to 400°C is 241.63MPa, and the strength reduction rate is 6.97%.

[0091] Example 9

[0092] A high-strength, high-temperature-resistant and ultraviolet-resistant composite film imitating a mussel structure and a preparation method thereof, comprising the following steps:

[0093] (1) Preparation of basalt nanosheets: Weigh a certain mass of basalt flakes and place them in a three-necked flask, add hydrochloric acid solution (HCl) thereto, and the ratio of basalt flakes to hydrochloric acid solution (HCl) is 0.4g:30mL, the concentration of hydrochloric acid solution is 4moL / L, and mechanical stirring is carried out for 24h in a water bath at 80℃ for surface etching reaction. After the reaction is completed, filter and wash until neutral (pH test paper test), and obtain basalt flakes with preliminary surface etching by vacuum drying, oven drying and freeze drying. Then weigh a certain mass of basalt flakes with preliminary surface etching and place them in a three-necked flask, add the prepared 2.0 concentration of hexadecylpyridinium bromide solution thereto, and the ratio of the preliminary surface etching basalt flakes to the hexadecylpyridinium bromide solution is 1.0g:80mL; the reaction temperature is 80℃, the stirring rate is 1000rpm, and the reaction time is 6h. After the reaction is completed, the mixture is filtered and washed to neutrality (pH test paper test), and ion-exchanged basalt flakes are obtained by freeze-drying. A certain mass of ion-exchanged basalt flakes is placed in a plastic beaker, and a certain volume of water is added thereto. The mass ratio of ion-exchanged basalt flakes to water is 0.1g:20mL. The beaker with the sample is transferred to a ball mill, a certain number of grinding balls are added to the ball mill, the ball mill is turned on, the power is adjusted to 1000W to start the reaction, and the reaction time is 0.6h. After the reaction is completed, the sample is taken out and placed in a glass bottle for standby use. After standing for 24h, the upper turbid liquid is taken out and basalt nanosheets are obtained by freeze-drying.

[0094] (2) Surface modification of basalt nanosheets: Weigh 1.0 g of the basalt nanosheets A prepared in step (1) and place them in a three-necked flask, then add hydrogen peroxide, ammonia water, and deionized water, with the mass ratio of basalt nanosheets A, hydrogen peroxide, ammonia water, and deionized water mixed solution being 0.2:1:1:20. Stir and react at room temperature, and after the reaction is completed, wash with deionized water and ethanol several times and store for later use.

[0095] (3) Preparation of aramid nanofibers: 1.5 g of potassium hydroxide was dissolved in 20 mL of deionized water to prepare a potassium hydroxide solution. 1 g of para-aramid chopped fibers was immersed in the potassium hydroxide solution for 1 h. 500 mL of dimethyl sulfoxide was added thereto and stirred at room temperature for 12 h. After the reaction was completed, 200 mL of a mixture of deionized water and ethanol (the mass ratio of deionized water to ethanol was 1:1) was uniformly added for protonation reduction. The fibers were repeatedly washed with deionized water and anhydrous ethanol until no excess dimethyl sulfoxide remained. The aramid nanofibers were then placed in a 4°C refrigerator for later use.

[0096] (4) Preparation of insulating film: The basalt nanosheets B with polyhydroxy groups on the surface obtained in step (2) are mixed with the aramid nanofibers in step (3), wherein the amount of basalt nanosheets B added is 5.0 wt% of the solid content of the aramid nanofibers, and the mixing method is ball milling for 30 min. After the reaction is completed, the film is filtered and dried to obtain a high-strength, high-temperature, and UV-resistant composite film with a mussel-like structure.

[0097] Figure 1 f is the SEM image of the cross section of the composite membrane in step (1), Figure 1 It can be found that the composite membrane has a very obvious mussel-like structure. As shown in Table 1, after the above-prepared nanosheets are added to the aramid nanofiber solution to prepare the composite membrane, the ultraviolet transmittance of the composite membrane is further reduced to 0.06, the tensile strength at room temperature is 138.45MPa, and the tensile strength when heated to 400°C is 124.32MPa, and the strength reduction rate is 10.21%. This is mainly because the amount of nanosheets added is increased, forming an obvious mussel-like structure, the bonding strength of the nanosheets and nanofibers is relatively high, and the nanosheets form a good stacking structure, which can effectively block ultraviolet erosion and can better isolate heat.

[0098] Table 1 is the UV transmittance and tensile strength data of the composite insulation film doped with aramid nanofibers and basalt nanosheets at different temperatures

[0099]

[0100] Note: The blank group is a composite coating prepared by replacing the basalt nanosheets in Example 1 with basalt flakes.

Claims

1. A method for preparing a high-strength, high-temperature-resistant and UV-resistant composite film with a mussel-like structure, It is characterized in that The following steps are involved: (1) Preparation of basalt nanosheets: placing basalt flakes in a hydrochloric acid solution, stirring at a set temperature to perform a surface etching reaction, and after the reaction is completed, filtering and washing until neutral to obtain a basalt flake with a preliminary surface etching; The basalt flakes with preliminary surface etching are placed in a solution of strontium chloride, tetrabutylammonium bromide and cetylpyridinium bromide, and an ion exchange reaction is carried out at a set temperature. After the reaction is completed, the basalt flakes are filtered and washed to obtain ion-exchanged basalt flakes; the basalt flakes with ion exchange are prepared into a mixed suspension, and then mechanically treated by ball milling, and then allowed to stand, and the upper turbid liquid is taken out, and after drying, basalt nanosheets A are obtained; (2) Surface modification of basalt nanosheets: stirring the basalt nanosheets A and a mixture of hydrogen peroxide / ammonia / deionized water to react, modifying the surface of the basalt nanosheets A to obtain polyhydroxylated basalt nanosheets B; (3) Preparation of insulating film: The polyhydroxylated basalt nanosheets B are mixed with aramid nanofibers and filtered to form a film, and then dried to obtain a high-strength, high-temperature-resistant and UV-resistant composite film with a mussel-like structure.

2. A method for preparing a high-strength, high-temperature-resistant and ultraviolet-resistant composite film with a mussel-like structure according to claim 1, It is characterized in that The specific preparation process of the aramid nanofiber is as follows: Potassium hydroxide is mixed with deionized water to obtain a potassium hydroxide solution, and then the para-aramid chopped fibers are immersed in the potassium hydroxide solution. After that, a dimethyl sulfoxide solution is added and stirred to react at room temperature. After the reaction is completed, a mixed solution of ethanol and deionized water is added to carry out a protonation reduction reaction, and after repeated washing, aramid nanofibers are obtained.

3. A method for preparing a high-strength, high-temperature-resistant and ultraviolet-resistant composite film with a mussel-like structure according to claim 2, It is characterized in that The potassium hydroxide solution contains potassium hydroxide and deionized water in an amount of 1.5 g:20 mL, the para-aramid chopped fibers and dimethyl sulfoxide in an amount of 1 g:500 mL; and the protonation reduction reaction contains ethanol and deionized water in an amount of 100 mL:100 mL.

4. A method for preparing a high-strength, high-temperature-resistant and ultraviolet-resistant composite film with a mussel-like structure according to claim 1, It is characterized in that The dosage ratio of basalt flakes to hydrochloric acid solution in step (1) is 0.4 g:30 mL, the concentration of the hydrochloric acid solution is 4 mol / L, the surface etching reaction temperature is 80° C., and the surface etching reaction time is 24 h.

5. A method for preparing a high-strength, high-temperature-resistant and ultraviolet-resistant composite film with a mussel-like structure according to claim 1, It is characterized in that The concentration of the strontium chloride solution in the step (1) is 0.1 mol / L to 1 mol / L, the concentration of the tetrabutylammonium bromide solution is 0.5 mol / L to 2 mol / L, the concentration of the cetylpyridinium bromide solution is 0.5 mol / L to 2 mol / L, the amount ratio of the basalt scales for preliminary surface etching to the strontium chloride solution is 1.0 g: 50 mL to 200 mL; the amount ratio of the basalt scales for preliminary surface etching to the tetrabutylammonium bromide solution is 1.0 g: 20 mL to 100 mL; the amount ratio of the basalt scales for preliminary surface etching to the cetylpyridinium bromide solution is 1.0 g: 20 mL to 80 mL; the ion exchange reaction temperature is 80° C., and the ion exchange reaction time is 6 hours.

6. A method for preparing a high-strength, high-temperature-resistant and ultraviolet-resistant composite film with a mussel-like structure according to claim 1, It is characterized in that In the step (1), the mass ratio of the ion-exchanged basalt flakes to water in the mixed suspension is 0.1 g: 20 mL to 50 mL, and the ball milling mechanical treatment time is 0.2 h to 0.6 h.

7. The method for preparing a high-strength, high-temperature-resistant and ultraviolet-resistant composite film with a mussel-like structure according to claim 1, It is characterized in that The mass ratio of the basalt nanosheets A, hydrogen peroxide, ammonia water and deionized water mixed solution in step (2) is 0.2 to 1:1:1:

20.

8. The method for preparing a high-strength, high-temperature-resistant and ultraviolet-resistant composite film with a mussel-like structure according to claim 1, It is characterized in that The amount of basalt nanosheets B added in step (3) is 0.1 wt% to 5.0 wt% of the solid content of the aramid nanofibers.

9. A high-strength, high-temperature-resistant and UV-resistant composite film imitating the structure of mussels. It is characterized in that Prepared based on the preparation method according to any one of claims 1 to 8.

10. A high-strength, high-temperature-resistant and UV-resistant composite film with a mussel-like structure according to claim 9, It is characterized in that The tensile strength of the high-strength, high-temperature-resistant and ultraviolet-resistant composite film with the mussel-like structure is 162.8 MPa to 269.4 MPa.

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