WO2021022777A1

WO2021022777A1 - Nano composite thin film having infrared absorption function, and manufacturing method therefor and application thereof

Info

Publication number: WO2021022777A1
Application number: PCT/CN2019/129758
Authority: WO
Inventors: 张学同; 吕婧
Original assignee: 中国科学院苏州纳米技术与纳米仿生研究所
Priority date: 2019-08-06
Filing date: 2019-12-30
Publication date: 2021-02-11
Also published as: CN110318257A

Abstract

The present application discloses a nano composite thin film having an infrared absorption function, a manufacturing method therefor and an application thereof. The nano composite thin film having an infrared absorption function comprises a porous thin film and an infrared absorption substance, the porous thin film having a connected three-dimensional network-like structure formed by mutually overlapping nanofibers and having a strong capillary force, and the infrared absorption substance being at least loaded within the three-dimensional network-like structure of the porous thin film. The nano composite thin film having an infrared absorption function provided in the present application has a wide infrared absorption band and a high infrared absorption rate, has a low cost and a simple preparation process, and can easily be produced on a large scale. The nano composite thin film can be directly used for filtering and thermal insulation and anti-infrared radiation, and can also overlap with the porous thin film to form a combined structure for thermal management or anti-infrared detection, having wide application prospects.

Description

Nano composite film with infrared absorption function and its manufacturing method and application

Technical field

This application relates to an infrared absorbing film, in particular to a nano composite film with infrared absorbing function and its manufacturing method and application, belonging to the technical field of nano new materials.

Background technique

Infrared absorbing materials refer to special functional materials that have strong absorption of infrared light in a certain band or certain bands. It can be a single compound or a composite of two or more materials. Infrared absorbing materials can be used to absorb the infrared radiation of the target to resist infrared detection, and can also shield the light source in the infrared region or prevent heat loss to play a role in heat insulation.

Traditional infrared absorbing materials are mostly powders, such as tungsten bronze, vanadium oxide, etc. The preparation process of such materials is complicated and it is difficult to process into large-size devices. The infrared absorption film has the advantages of light weight, small thickness, detachability, etc., so it is widely used. Therefore, researchers continue to strive to improve the film-forming properties of infrared absorbing materials. At present, there are two commonly used methods. One is to physically mix infrared absorbing material powders with polymers that can easily form films. For example, CN201711396606 discloses A thermoplastic polyurethane elastomer (TPU) film with infrared absorption function and a preparation method thereof. The infrared absorption material polyaniline, polypyrrole, polycarbonate, polyvinylpyrrolidone, TPU particles, and nano silica are mixed and extruded , The TPU film is obtained, the film has good flexibility and mechanical properties, but the physical mixing has the problem of uneven dispersion of infrared absorbing substances, and the infrared absorption rate is only 60%-75%. Another method to improve the film-forming properties of infrared absorbing substances is the chemical compound method. For example, CN201811226654 uses the hydrolysis process of ethyl orthosilicate and the sol-gel process of polyvinyl alcohol and nano-silica to prepare infrared absorbing materials. The flexible composite film, but only in the 3μm-3.4μm and 8μm-10μm wave band with higher absorption rate.

In addition, by using the capillary action of porous materials to adsorb infrared absorbing substances, infrared absorbing materials with specific shapes can be prepared. For example, CN105369380A discloses a phase-change temperature-regulating fiber, which absorbs and blends porous absorbent materials, polymer phase-change materials and substances with far-infrared absorption function, and then mixes them with cellulose ionic liquid to prepare spinning dope, using solvent method The phase-change temperature-regulating fiber was prepared. The phase-change temperature-regulating fiber absorbs both far-infrared light and visible light. However, the infrared absorption performance of the 3μm-15μm infrared waveband and the film-forming properties of the spinning dope were not studied. In view of the demand for infrared absorbing films in the fields of light filtering, heat insulation, infrared radiation prevention, thermal management and anti-infrared reconnaissance, there is an urgent need to develop an infrared absorbing film with simple process, low cost, and high infrared absorption rate in the 3μm-15μm band.

Summary of the invention

The main purpose of this application is to provide a nano-composite film with infrared absorption function and its manufacturing method and application to overcome the deficiencies in the prior art.

In order to achieve the foregoing invention objectives, the technical solutions adopted in this application include:

On the one hand, the embodiments of the present application provide a nanocomposite film with infrared absorption function, which includes a porous film and an infrared absorbing substance. The porous film has a connected three-dimensional network structure formed by overlapping nanofibers with each other. Capillary force, the infrared absorbing substance is loaded at least in the three-dimensional network structure of the porous film.

Further, the infrared absorbing substance is distributed on the surface of the nanofiber and the internal pores of the porous film.

Further, the nanofibers include any one or a combination of two or more of aramid nanofibers, cellulose nanofibers, and polyimide nanofibers, but are not limited thereto.

Further, the porous film has a thickness of 100-1000 μm, a density of 0.01-0.10 g/cm ³ , a porosity of 80-99.8%, and a thermal conductivity of 0.02-0.06 W/mK.

Further, the diameter of the nanofibers in the porous film is 2-100 nm.

Further, the content of the infrared absorbing substance in the nanocomposite film is 1-99wt%, preferably 30-98wt%.

Further, the infrared absorbing substance includes any one or a combination of two or more of polyethylene glycol, polyol, fatty amine, higher fatty alcohol, and higher fatty acid, but is not limited thereto.

Further, the infrared absorption rate of the nanocomposite film with infrared absorption function in the 3 μm-15 μm infrared band is adjustable, and the absorption rate is 50%-99.8%, preferably 90%-99.8%.

Further, the thickness of the nanocomposite film with infrared absorption function is 100-250 μm, and the tensile strength is 0.1-300 MPa.

On the other hand, the embodiments of the present application also provide a method for manufacturing the aforementioned nanocomposite film with infrared absorption function, which includes:

Providing a porous film having a connected three-dimensional network structure formed by overlapping nanofibers;

Filling the molten infrared absorbing substance into the three-dimensional network structure of the porous film to obtain the nanocomposite film with infrared absorbing function, or,

The infrared absorbing substance solution is filled into the three-dimensional network structure of the porous film, and the nano composite film with infrared absorbing function is obtained after drying treatment.

In some more specific embodiments, the manufacturing method may include: placing the infrared absorbing material in a vacuum oven and heating it to above the melting temperature of the infrared material, immersing the porous film in the molten infrared absorbing material, and The porous film immersed in the molten infrared absorbing material is placed in a vacuum oven for 1-24 hours. Through capillary action, the infrared absorbing material is loaded into the three-dimensional network structure of the porous film, and the excess infrared absorbing material on the surface is taken out and removed , And then obtain the nanocomposite film with infrared absorption function.

In some more specific embodiments, the manufacturing method may further include: first dissolving the infrared absorbing material in a solvent to form an infrared absorbing material solution, immersing the porous film in the infrared absorbing material solution, and leaving it to stand for 1- After 24h, through capillary action, the infrared absorbing material is loaded into the three-dimensional network structure of the porous film, and the excess infrared absorbing material on the surface is taken out and removed. After freeze drying or atmospheric drying treatment, the described nanometer with infrared absorption function is obtained. Composite film.

Wherein, the concentration of the infrared absorbing substance solution is 1-90% by weight, and the solvent in the infrared absorbing substance solution includes any one or more of water, ethanol, tert-butanol, acetone, and nitrogen methyl pyrrolidone Combination, but not limited to this.

The nano-composite film with infrared absorption function provided in the present application has a simple preparation process, mild and controllable conditions, easy realization of large-scale production, and high infrared absorption rate.

The embodiments of the present application also provide the application of the described nanocomposite film with infrared absorption function in the fields of light filtering and heat insulation, infrared radiation prevention, thermal management, and infrared reconnaissance resistance.

For example, the nanocomposite film with infrared absorption function can be directly used for light filtering and heat insulation and infrared radiation prevention due to its high infrared absorption rate.

The embodiment of the present application also provides a combined structure that can resist infrared detection, which includes a laminated heat insulation layer and the nanocomposite film with infrared absorption function, and the heat insulation layer is a porous film.

Further, the porous film has a connected three-dimensional network structure formed by overlapping a plurality of nanofibers, and the nanofibers include any one of aramid nanofibers, cellulose nanofibers, and polyimide nanofibers. Or a combination of two or more, but not limited to this.

Further, the combined structure capable of resisting infrared detection includes 1-5 layers of the heat insulation layer, the thickness of the heat insulation layer is 100-1000 μm, and the thermal conductivity is 0.02-0.06 W/m·K.

The embodiment of the present application also provides a method for using a combined structure capable of resisting infrared detection, which includes: covering the combined structure capable of resisting infrared detection on a high-temperature target, wherein the infrared absorbing function The nanocomposite film is arranged on the side away from the high-temperature target.

The nanocomposite film with infrared absorption function in the present application can also be tailored according to the size of different targets, and can be coated on irregular surfaces.

Among them, the porous film is the heat insulation layer, which can reduce the temperature of the high-temperature target object to match the ambient temperature; the nanocomposite film with infrared absorption function has high infrared absorption rate, and the infrared light emitted by the high-temperature target cannot pass through, so it covers this A high-temperature target with a combined structure is fused with the background in infrared photos, which can counter infrared reconnaissance.

With the above technical solutions, the nanocomposite film with infrared absorption function provided by the present application is composed of a porous film loaded with infrared absorbing material, and the porous film is formed by overlapping nanofibers with each other, and has a connected three-dimensional network structure with adjustable The density, porosity, thermal conductivity, etc., and the capillary force is strong. The infrared absorbing substance is adsorbed on the surface of the nanofibers and the pores of the porous film. The infrared absorption function nano composite film has a wide infrared absorption band, high infrared absorption rate, and a very broad application prospect.

Compared with the prior art, the nanocomposite film with infrared absorption function provided by the present application has a wider infrared absorption band and a higher infrared absorption rate, at the same time, it has low cost, simple preparation process, easy to achieve large-scale production, and can be directly It is used for filtering light and heat insulation and preventing infrared radiation. It can also be superimposed with porous film to form a combined structure for thermal management or anti-infrared reconnaissance. The application prospect is very broad.

Description of the drawings

In order to more clearly describe the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings that need to be used in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only These are some embodiments described in this application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative work.

Fig. 1 is a schematic structural diagram of a nanocomposite film with infrared absorption function in a typical embodiment of the present application;

2a-2c are respectively scanning electron micrographs of a nanocomposite film with infrared absorption function obtained in Example 1, Example 2, and Example 3 of the present application;

3 is a TG curve of a nanocomposite film with infrared absorption function obtained in Example 4 of the present application;

4 is an FT-IR spectrum of a nanocomposite film with infrared absorption function obtained in Example 5 to Example 8 of the present application;

FIG. 5 is an infrared photograph of a nano composite film with infrared absorption function obtained in Example 9 of the present application covering a heating plate;

Fig. 6 is an infrared photograph of a composite structure of a porous film and a nanocomposite film with infrared absorption function obtained in Example 10 of the present application and covered on a heating plate.

detailed description

In view of the shortcomings in the prior art, the inventor of this case was able to propose the technical solution of the application after long-term research and extensive practice. The technical solution, its implementation process and principle will be further explained as follows.

The technical solution of the present application will be further described in detail below through several embodiments in conjunction with the drawings. However, the selected embodiments are only used to illustrate the application, and do not limit the scope of the application, and those skilled in the art can make adjustments according to actual conditions.

Example 1

A polyethylene glycol aqueous solution with a mass fraction of 30% was prepared, and an aramid nanofiber porous film with a thickness of 200μm, a porosity of 95%, a density of 29mg/cm ³ and a thermal conductivity of 0.036W/m·K was placed on it. In the polyethylene glycol aqueous solution, stand for 12 hours and then take it out, remove the excess polyethylene glycol aqueous solution on the surface, and dry under normal pressure to obtain a nano composite film with infrared absorption function. FIG. 2a shows the SEM photo of the nanocomposite film with infrared absorption function obtained in this embodiment, and other parameters are shown in Table 1.

Example 2

A 50% mass fraction of cetyl alcohol aqueous solution was prepared, and a aramid nanofiber porous film with a thickness of 500 μm, a porosity of 95%, a density of 29 mg/cm ³ and a thermal conductivity of 0.036 W/m·K was placed on the ten In the hexanol aqueous solution, stand for 12 hours and then take it out, remove the excess cetyl alcohol aqueous solution on the surface, and dry under normal pressure to obtain a nano composite film with infrared absorption function. FIG. 2b shows the SEM photo of the nanocomposite film with infrared absorption function obtained in this embodiment, and other parameters are shown in Table 1.

Example 3

Heat the stearic acid in an oven until it melts completely, and immerse the aramid nanofiber porous film with a thickness of 1000μm, a porosity of 95%, a density of 29mg/cm ³ and a thermal conductivity of 0.036W/m·K to the molten state And put it in a vacuum oven at 80℃ for 12h, then take it out, put it on the filter paper, and put it back in the vacuum oven at 80℃. The filter paper absorbs the excess stearic acid on the film surface and remove it from the oven after 6h. Take it out and cool down at room temperature to obtain a nanocomposite film with infrared absorption function. FIG. 2c shows the SEM photo of the nanocomposite film with infrared absorption function obtained in this embodiment, and other parameters are shown in Table 1.

Example 4

Heat polyethylene glycol in an oven until it melts completely, and immerse the aramid nanofiber porous film with a thickness of 500μm, a porosity of 95%, a density of 29mg/cm ³ and a thermal conductivity of 0.036W/m·K to melt. And put it in a vacuum oven at 80℃ for 12h, then take it out, put it on the filter paper, and put it back in the vacuum oven at 80℃. The filter paper absorbs the excess polyethylene glycol on the surface of the film. After 6h Take it out of the oven and cool at room temperature to obtain a nanocomposite film with infrared absorption function. FIG. 3 shows the TG curve of the nanocomposite film with infrared absorption function obtained in this embodiment, and other parameters are shown in Table 1.

Example 5

The cellulose nanofiber porous film with a thickness of 100μm, a porosity of 90%, a density of 42mg/cm ³ and a thermal conductivity of 0.038W/m·K was immersed in the molten polyethylene glycol and kept at 80℃ Put it in a vacuum oven for 12 hours and then take it out, place it on the filter paper, and then put it back in the vacuum oven at 80°C. The filter paper absorbs the excess polyethylene glycol on the surface of the film. After 6 hours, it is taken out of the oven and cooled at room temperature to obtain an infrared absorption function. Nano composite film. FIG. 4 shows the infrared transmittance of the nanocomposite film with infrared absorption function obtained in this embodiment, and other parameters are shown in Table 1.

Example 6

The cellulose nanofiber porous film with a thickness of 150μm, a porosity of 90%, a density of 42mg/cm ³ and a thermal conductivity of 0.038W/m·K was immersed in the molten polyethylene glycol and kept at 80℃ Put it in the vacuum oven for 12 hours and then take it out, place it on the filter paper, and then put it back in the vacuum oven at 80°C. The filter paper absorbs the excess polyethylene glycol on the surface of the film. After 6 hours, it is taken out of the oven and cooled at room temperature to achieve infrared absorption. Nanocomposite film. FIG. 4 shows the infrared transmittance of the nanocomposite film with infrared absorption function obtained in this embodiment, and other parameters are shown in Table 1.

Example 7

The cellulose nanofiber porous film with a thickness of 200μm, a porosity of 90%, a density of 42mg/cm ³ and a thermal conductivity of 0.038W/m·K is immersed in the molten polyethylene glycol, and a vacuum oven at 80°C After standing for 12h, take it out, put it on the filter paper, and put it back into the vacuum oven at 80℃. The filter paper absorbs the excess polyethylene glycol on the surface of the film. After 6h, it is taken out of the oven and cooled at room temperature to obtain a nanocomposite with infrared absorption function. film. FIG. 4 shows the infrared transmittance of the nanocomposite film with infrared absorption function obtained in this embodiment, and other parameters are shown in Table 1.

Example 8

The cellulose nanofiber porous film with a thickness of 250μm, a porosity of 90%, a density of 42mg/cm ³ and a thermal conductivity of 0.038W/m·K is immersed in the molten polyethylene glycol, and a vacuum oven at 80°C After standing for 12h, take it out, put it on the filter paper, and put it back into the vacuum oven at 80℃. The filter paper absorbs the excess polyethylene glycol on the surface of the film. After 6h, it is taken out of the oven and cooled at room temperature to obtain a nanometer with infrared absorption function. Composite film. FIG. 4 shows the infrared transmittance of the nanocomposite film with infrared absorption function obtained in this embodiment, and other parameters are shown in Table 1.

Example 9

A cellulose nanofiber porous film with a thickness of 200μm, a porosity of 85%, a density of 48mg/cm ³ and a thermal conductivity of 0.042W/m·K was placed in the molten eicosane mixture and placed in an oven at 80°C. After 12h, take it out and place it on filter paper. Place it in a vacuum oven at 80°C for 6h to remove excess eicosane on the surface. Cool at room temperature to obtain a nanocomposite film with infrared absorption function. The nano-composite film with infrared absorption function is wrapped on an electric heating plate, and a voltage of 3V is applied. The temperature of the heating plate gradually rises. The infrared camera is used to photograph it. Figure 5 shows the infrared absorption function obtained in this embodiment. The infrared photo of the nanocomposite film covering the heating plate, please refer to Table 1 for other parameters.

Example 10

A polyamide nanofiber porous film with a thickness of 200μm, a porosity of 90%, a density of 43mg/cm ³ and a thermal conductivity of 0.04W/m·K is placed in the molten hexadecylamine mixture in an oven at 80°C After standing for 12 hours, take it out, and remove excess hexadecylamine on the surface at 80°C to obtain a nanocomposite film with infrared absorption function. Cover the aforementioned polyamide nanofiber porous film on an electric heating plate, and then coat a layer of nanocomposite film with infrared absorption function, apply a voltage of 3V, the temperature of the heating plate gradually rises, and use an infrared camera to photograph it, Figure 6 Shows the infrared photo of the porous film obtained in this embodiment and the nanocomposite film covering combination structure with infrared absorption function on the heating plate. For other parameters, please refer to Table 1.

Table 1. Structure and performance parameters of the nanocomposite film with infrared absorption function obtained in Examples 1-10

Through Examples 1-10, it can be found that the infrared absorption film obtained by the above technical solution of the application has excellent shape stability, high infrared absorption material loading, high infrared absorption rate, etc.; and the preparation process is simple and easy Realize mass production.

In addition, the inventor of the present case also conducted experiments with the other raw materials and conditions listed in this specification with reference to the methods of Examples 1-10, and also obtained good shape stability, high infrared absorption material loading, and high infrared Infrared absorption film with excellent performance such as absorptivity.

It should be understood that the above-mentioned embodiments only illustrate the technical ideas and features of the application, and their purpose is to enable those familiar with the technology to understand the content of the application and implement them accordingly, and cannot limit the protection scope of the application. All equivalent changes or modifications made according to the spirit and essence of this application shall be covered by the protection scope of this application.

Claims

A nano-composite film with infrared absorption function, which is characterized by comprising a porous film and an infrared absorbing material. The porous film has a connected three-dimensional network structure formed by overlapping nanofibers, and the infrared absorbing material is at least loaded on the In the three-dimensional network structure of the porous film.
The nanocomposite film with infrared absorption function according to claim 1, wherein the infrared absorption material is distributed on the surface of the nanofibers and the internal pores of the porous film; and/or, the nanofibers include Any one or a combination of two or more of aramid nanofibers, cellulose nanofibers, and polyimide nanofibers; and/or, the porous film has a thickness of 100-1000 μm and a density of 0.01-0.10 g/ cm 3 , the porosity is 80-99.8%, and the thermal conductivity is 0.02-0.06W/mK; and/or, the diameter of the nanofibers in the porous film is 2-100nm; and/or, the infrared absorption function The content of the infrared absorbing material in the nanocomposite film is 1-99wt%, preferably 30-98wt%; and/or, the infrared absorbing material includes polyethylene glycol, polyol, fatty amine, higher fatty alcohol, higher fatty acid Any one or a combination of two or more of them.
The nanocomposite film with infrared absorption function according to claim 1, wherein the infrared absorption band of the nanocomposite film with infrared absorption function is 3-15 μm, and the infrared absorption rate is 50-99.8%, preferably 90 %-99.8%; and/or, the thickness of the nanocomposite film with infrared absorption function is 100-250 μm, and the tensile strength is 0.1-300 MPa.
The manufacturing method of the nanocomposite film with infrared absorption function according to any one of claims 1 to 3, which is characterized by comprising:

Providing a porous film having a connected three-dimensional network structure formed by overlapping nanofibers;

Filling the molten infrared absorbing substance into the three-dimensional network structure of the porous film to obtain the nanocomposite film with infrared absorbing function, or,

The infrared absorbing substance solution is filled into the three-dimensional network structure of the porous film, and the nano composite film with infrared absorbing function is obtained after drying treatment.
The manufacturing method according to claim 4, characterized in that it comprises: placing the porous film in a molten infrared absorbing material, leaving it to stand for 1-24 hours and then taking it out to obtain the nanocomposite with infrared absorbing function film.
The manufacturing method according to claim 4, characterized in that it comprises: placing the porous film in an infrared absorbing material solution, letting it stand for 1-24 hours, and then taking it out and drying to obtain the nanocomposite film with infrared absorbing function And/or, the concentration of the infrared absorbing substance solution is 1-90wt%; and/or, the solvent in the infrared absorbing substance solution includes any of water, ethanol, tert-butanol, acetone, and nitrogen methyl pyrrolidone One or a combination of two or more.
The use of the nanocomposite film with infrared absorption function according to any one of claims 1 to 3 in the fields of light filtering and heat insulation, infrared radiation prevention, thermal management and anti-infrared reconnaissance.
A combined structure capable of resisting infrared detection, characterized in that it comprises a laminated heat insulation layer and the nanocomposite film with infrared absorption function according to any one of claims 1 to 3, and the heat insulation layer is porous Membrane, the porous membrane has a connected three-dimensional network structure formed by overlapping nanofibers.
The combined structure capable of resisting infrared detection according to claim 8, wherein the nanofibers comprise any one or more of aramid nanofibers, cellulose nanofibers, and polyimide nanofibers. And/or, the combined structure that can resist infrared detection includes 1-5 layers of the heat insulation layer; preferably, the thickness of the heat insulation layer is 100-1000 μm, and the thermal conductivity is 0.02-0.06W /m·K.
A method for using a combined structure capable of resisting infrared detection, characterized in that it comprises: covering the combined structure capable of resisting infrared detection of claim 8 or 9 on a high-temperature target, wherein the infrared absorbing function The nanocomposite film is arranged on the side away from the high-temperature target.