CN115748238A - A kind of airgel-based energy-absorbing material, its preparation method and application - Google Patents

Abstract

The invention discloses an airgel-based energy-absorbing material, its preparation method and application. The airgel-based energy-absorbing material includes: a porous airgel material, which includes a connected three-dimensional porous network structure formed by overlapping nanofibers; and, loaded in the porous airgel material Energy-absorbing substances and selectively added or not added functional additives are wrapped on the nanofibers and embedded in the three-dimensional porous network structure. The preparation method includes: filling energy-absorbing substances, selectively added or not added functional additives into the porous airgel material through in-situ polymerization or solution-assisted filling, and then drying to obtain an airgel-based energy-absorbing material. Material. The airgel-based energy-absorbing material of the present invention can be prepared into any size and shape, the structure can be designed, and the preparation process is simple, and it is easy to realize large-scale production, and can be applied to shock absorption and anti-noise, impact protection, energy absorption, etc. field.

Description

A kind of airgel-based energy-absorbing material, its preparation method and application

technical field

The invention relates to an energy-absorbing material, in particular to an airgel-based energy-absorbing material, its preparation method and application, and belongs to the technical field of new nanometer materials.

Background technique

In recent years, with the continuous improvement of people's awareness of personal protection, equipment transportation or use, the demand for lightweight protective energy-absorbing materials has gradually increased. For example, in a high-risk working environment, it is necessary to do a good job of personal protection to ensure personal safety; in industrial production such as bridges and buildings, dampers are needed to dissipate unnecessary or harmful energy to the system; in automobiles, aerospace, etc. In the field, it is also necessary to absorb a large amount of impact energy to ensure the safety and normal operation of personnel, vehicles and spacecraft. Therefore, there is an urgent need to develop light and comfortable protective equipment with excellent energy-absorbing properties.

Shear thickening materials, as a typical representative of a class of materials with good energy absorption properties, have a very wide range of application scenarios. Shear thickening materials, also known as non-Newtonian fluids, usually exhibit special fluid behavior, and their most distinctive feature is the shear thickening effect, that is, under a certain range of shear rates, the The viscosity of the material will increase sharply with the increase of the shear rate. When it is not stressed, it is light and soft. At this time, it is comfortable to wear and easy to deform. When it is impacted by an external force, the material will quickly harden. It has a good ability to absorb impact energy, and after impact, the material will return to a soft state. In recent years, shear thickening materials have attracted the attention of academia and industry in the fields of human body protection due to their excellent lightness, protection, comfort and flexibility.

At present, shear thickening materials are mainly divided into the following two types:

(1) Shear thickening liquid: Shear thickening liquid is prepared by directly dispersing particles in a liquid, the particles are usually silica particles, and the liquid can be ethylene glycol, polyethylene glycol 200, etc. CN115071237A provides a composite film with a sandwich structure by placing the middle layer of the shear thickening liquid between two layers of polymer films, which can not only maintain the properties of the polymer film itself such as modulus, strength and flexibility, but also It is also able to absorb shock or vibration energy and thus has excellent toughness. CN114921083A discloses a polyurethane-polyurea double-layer shear thickening liquid microcapsule material, which can improve the impact resistance of polymer materials, and at the same time make the shear thickening liquid applied to the processing fluidity of polymer composite materials to improve improve. However, the use of shear thickening fluid often faces the following problems: ① It is difficult for particles to disperse uniformly in the liquid matrix, resulting in a decrease in performance; ② Shear thickening fluid is a liquid, and its unique rheological properties exist in a narrow concentration range, it is difficult to be applied in practical applications; ③ Shear thickening liquid is exposed to the air for a long time, and it is easy to absorb moisture in the air, thereby reducing the shear thickening performance; ④ Shear thickening liquid tends to lose It is filled into the porous material, and once the porous material is destroyed, the liquid is easy to flow out; ⑤ The temperature requirements are relatively strict, and it is easy to fail at higher or lower temperatures.

(2) Shear hardening gel: mainly refers to organopolyborosiloxane material, which can deform freely at a low shear rate. When the shear rate increases sharply, the material changes suddenly to show a hard Solid properties, the viscosity will rise sharply, and the system will undergo changes similar to phase transitions. The shear-hardening gel overcomes many shortcomings of the shear-thickening fluid, and has good thermal stability, which greatly expands the application prospects of the shear-thickening material. CN105385163A provides a preparation method of a shear-thickening gel-based shock-absorbing and energy-absorbing material, which will spontaneously change from soft to hard when subjected to impact, and absorb energy, thereby effectively playing a protective role. CN107474544A discloses a lightweight shear thickening gel, which uses hollow microspheres to modify the traditional shear thickening gel, so that the overall weight of the shear thickening gel is light and the viscosity is reduced. The same mass of shear-thickening gel is applied to the sample, and the protective effect of adding hollow microspheres is obviously enhanced. CN104862975A provides a preparation method of an anti-fragmentation fabric with a shear thickening effect, and the fabric has a good energy absorption effect. However, there are still the following problems in shear-hardening gels: ①Shear-hardening gels are limited by creep and no fixed shape, so they cannot be used alone; ②Shear-hardening gels are immersed in traditional material forms, such as In the inert aramid fiber, due to the poor bonding strength between the interface layers, interface failure is prone to occur, resulting in a decrease in performance over time; ③The volume ratio of the effective shear hardening gel is too small to function.

Based on this, it is still a challenge to develop a new type of airgel-based energy-absorbing material to overcome the deficiencies of existing shear-thickening materials to meet the requirements of light weight, comfort, softness, and good energy-absorbing performance in the practical application of protective materials. problems that urgently need to be resolved.

Contents of the invention

The main purpose of the present invention is to provide an airgel-based energy-absorbing material and its preparation method, so as to overcome the deficiencies of the prior art.

Another object of the present invention is to provide the use of the aforementioned airgel-based energy-absorbing material.

In order to realize the aforementioned object of the invention, the present invention adopts the following technical solutions:

An embodiment of the present invention provides an airgel-based energy-absorbing material, which includes:

A porous airgel material as a substrate, which includes a connected three-dimensional porous network structure formed by overlapping nanofibers;

And, the energy-absorbing substances loaded in the porous airgel material and functional additives selectively added or not added, the functional additives can strengthen the base material on the one hand, and on the other hand can introduce conductivity, properties such as heat conduction. The energy-absorbing substances and functional additives are wrapped on the nanofibers and embedded in the three-dimensional porous network structure. When the external strain rate or shear rate changes, the energy-absorbing substances can absorb and dissipate a large amount of impact energy, thereby protecting other materials or devices from damage. Wherein, the energy-absorbing substance includes any one or two or more of polydimethylsiloxane, polyborosiloxane, soft and hard phase change materials, plasticine, natural rubber, neoprene, and nitrile rubber. The combination.

The embodiment of the present invention also provides a preparation method of the aforementioned airgel-based energy-absorbing material, which includes:

Provide porous airgel materials;

By means of in-situ polymerization or solution-assisted filling, the energy-absorbing material and selectively added or not added functional additives are filled into the porous airgel material, and then dried to obtain the airgel-based energy-absorbing material.

The embodiment of the present invention also provides the application of the airgel-based energy-absorbing material in the fields of shock absorption and noise resistance, impact protection or energy absorption.

Compared with the prior art, the beneficial effects of the present invention are at least:

1) The airgel matrix structure used in the airgel-based energy-absorbing material provided by the present invention can be individually designed, and the energy-absorbing material can get rid of the restrictions of creep and no fixed shape;

(2) The airgel matrix used in the airgel-based energy-absorbing material provided by the present invention has multiple active sites inside and on the surface, and the bonding strength between the interface layers is large;

(3) The airgel matrix used in the airgel-based energy-absorbing material provided by the present invention is composed of high-performance nanofibers, which can enhance the mechanical properties of the energy-absorbing substances confined in nanometers;

(4) The mass fraction of the energy-absorbing substance in the airgel-based energy-absorbing material provided by the invention can be as high as 99%, which is beneficial to give full play to the performance of the energy-absorbing substance; at the same time, the preparation process is simple, easy to realize large-scale production, and can be applied In the fields of shock absorption and noise resistance, impact protection, energy absorption and so on.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention 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 accompanying drawings in the following description are only These are some embodiments described in the present invention. Those skilled in the art can also obtain other drawings based on these drawings without creative work.

Fig. 1 is a schematic structural view of an airgel-based energy-absorbing material in a typical embodiment of the present invention;

Fig. 2 is the thermogravimetric graph of the aramid airgel film-based energy-absorbing material obtained in Example 1 of the present invention;

Fig. 3 is the infrared spectrogram of the aramid airgel fiber-based energy-absorbing material obtained in Example 2 of the present invention;

Fig. 4 is the optical photograph of the aramid airgel honeycomb-based energy-absorbing material obtained in Example 3 of the present invention;

Fig. 5 is the optical photograph of the cellulose airgel film-based energy-absorbing material obtained in Example 4 of the present invention;

Figure 6 is an optical photo of the 3D printed cellulose airgel lattice-based energy-absorbing material obtained in Example 5 of the present invention;

Figure 7 is a quasi-static stress-strain graph of the cellulose airgel block-based energy-absorbing material obtained in Example 6 of the present invention;

Figure 8 is a photo showing the flexibility of the polyimide airgel fiber-based energy-absorbing material obtained in Example 7 of the present invention;

Fig. 9 is an internal morphology diagram of the cellulose airgel fiber-based energy-absorbing material obtained in Example 8 of the present invention;

Fig. 10 is a high-speed impact curve of the silk protein airgel film-based energy-absorbing material obtained in Example 9 of the present invention;

Fig. 11 is a high-speed impact curve of the silver nanowire airgel block-based energy-absorbing material obtained in Example 10 of the present invention.

Detailed ways

The shear hardening gel has the following problems: ①The shear hardening gel is limited by creep and has no fixed shape, so it cannot be used alone; ②The shear hardening gel is immersed in the traditional material form, such as inert aramid fiber In , due to the poor bonding strength between the interfacial layers, interface failure is prone to occur, resulting in a decrease in performance over time; ③The volume ratio of the effective shear hardening gel is too small to function. These disadvantages make the protective properties of shear hardening gels unable to meet the needs of practical applications.

In view of the deficiencies in the prior art, the inventor of this case has been able to propose the technical solution of the present invention after long-term research and extensive practice, mainly to develop a new type of airgel-based energy-absorbing material to overcome the deficiencies of existing materials, and to Meet the light weight, comfort, and good energy-absorbing performance in the practical application of protective materials, and illustrate a series of applications of this airgel-based energy-absorbing material. The technical solution, its implementation process and principle will be further explained as follows.

Specifically, as an aspect of the technical solution of the present invention, the structure of the airgel-based energy-absorbing material involved can be seen in Figure 1. The airgel-based energy-absorbing material is made of porous airgel material The substrate is loaded with energy-absorbing substances, and functional additives that are selectively added or not added. The porous airgel material has a specific and arbitrary macroscopic structure that can be designed, and the interior is formed by overlapping nanofibers, and has a connected three-dimensional porous network structure. The energy-absorbing substances and functional additives are wrapped on the nanofibers and embedded in the three-dimensional porous network structure.

Furthermore, the airgel matrix used in the airgel-based energy-absorbing material of the present invention is composed of high-performance nanofibers, which can enhance the mechanical properties of the energy-absorbing substances confined in nanometers. Moreover, there are multiple active sites inside and on the surface of the airgel matrix, and the bonding strength between the interface layers is strong.

In some preferred embodiments, the types of nanofibers constituting the porous airgel material include but are not limited to aramid nanofibers, cellulose nanofibers, polyimide nanofibers, silk protein nanofibers, silver nanofibers Any one or a combination of two or more of these.

In some preferred embodiments, the macroscopic structure of the porous airgel material includes, but is not limited to, any one or a combination of two or more of honeycomb, P-shaped, three-dimensional lattice, film, fiber, block, etc.

In some preferred embodiments, the interior of the porous airgel material has a hierarchical porous network structure, and the hierarchical porous network structure consists of micropores with a pore diameter of 2 nm or less, mesopores with a pore diameter of 2 nm to 50 nm, and pores with a pore diameter of 50 nm to 50 nm. Composed of macropores of 10 cm, the porosity of the porous airgel material is 50-99.99%, the density is 0.1-1500 mg/cm ³ , the specific surface area is 50-2500 m ² /g, and the pore volume is 0.1-15 cm ³ /g .

Furthermore, when the external strain rate or shear rate changes, the energy-absorbing substance can absorb and dissipate a large amount of impact energy, thereby protecting other materials or devices from being damaged.

In some preferred embodiments, the energy-absorbing substances include but are not limited to polydimethylsiloxane, polyborosiloxane, soft and hard phase change materials, plasticine, natural rubber, neoprene, nitrile rubber, etc. any one or a combination of two or more.

In some preferred embodiments, the content of the energy-absorbing substance in the airgel-based energy-absorbing material is 30wt%-99wt%. The mass fraction of the energy-absorbing substance in the airgel-based energy-absorbing material of the present invention can be as high as 99%, which is beneficial to give full play to the performance of the energy-absorbing substance.

In some preferred embodiments, the functional additives include but are not limited to calcium carbonate, carbon nanotubes, graphene, transition metal nitrides/carbides (MXene), metals (such as gold nanoparticles), silica particles, etc. any one or a combination of two or more. Further, the functional additives can strengthen the base material on the one hand, and can introduce properties such as electrical conductivity and heat conduction to the base material on the other hand.

Further, the content of functional additives in the airgel-based energy-absorbing material is 0wt%-30wt%.

In some preferred embodiments, the energy absorption value of the airgel-based energy-absorbing material is 0.1-1000 J/g.

Another aspect of the embodiments of the present invention provides a method for preparing an airgel-based energy-absorbing material, which includes:

Provide porous airgel materials;

By means of in-situ polymerization or solution-assisted filling, the energy-absorbing material and selectively added or not added functional additives are filled into the porous airgel material, and then dried to obtain the airgel-based energy-absorbing material.

In some preferred embodiments, the preparation method specifically includes:

(1) Select a porous airgel material with a specific macrostructure and supercapillary force as the substrate;

(2) Introduce energy-absorbing substances and functional additives into the three-dimensional porous network structure of porous airgel materials by means of in-situ polymerization or solution-assisted filling;

(3) removing excess energy-absorbing substances on the surface and drying to obtain an airgel-based composite energy-absorbing material with high energy absorption.

In some specific embodiments, the preparation method of the porous airgel material includes: at least wet spinning method, confined sol-gel reaction spinning method, freeze-dry spinning method, template method, 3D printing method The porous airgel material is prepared by any one or a combination of methods of blade coating, blade coating, but not limited thereto.

In some specific embodiments, the drying includes at least any one of freeze drying, vacuum drying, or normal pressure drying, but is not limited thereto.

In some specific embodiments, the in-situ polymerization method includes: placing the energy-absorbing material prepolymer in a reaction container, and making it contact with the porous airgel material, standing for 1h-24h, taking it out and The excess energy-absorbing material prepolymer on the surface is removed, and then the energy-absorbing material prepolymer is polymerized in situ, and then dried to prepare an airgel-based energy-absorbing material.

Further, the energy-absorbing material prepolymer may include an energy-absorbing material precursor (such as soft and hard phase change material prepolymer benzyl methacrylate monomer), an initiator (such as 1-hydroxycyclohexyl phenyl ketone photoinitiator), cross-linking agent (such as ethylene glycol dimethacrylate) and ionic liquid (such as 1-ethyl-3-methylimidazole bistrifluoromethanesulfonimide salt).

Further, the energy-absorbing material prepolymer may also include energy-absorbing material precursors (such as chloroprene monomers), emulsifiers (such as rosin acid soap emulsifiers), initiators (such as potassium persulfate), relative Molecular weight modifiers (such as n-dodecanethiol), vulcanizing agents (such as sulfur) and solvents (such as water), etc., but not limited thereto.

Further, the in-situ polymerization method specifically includes the following steps:

Put the energy-absorbing material prepolymer in the container, immerse the porous airgel material in it, let it stand for 1h to 24h, take out and remove the excess energy-absorbing material prepolymer on the surface, and then place it in a specific environment to make the energy-absorbing material The prepolymer is polymerized in situ, followed by freeze-drying, vacuum-drying or normal-pressure drying to obtain an airgel-based energy-absorbing material.

In some specific embodiments, the solution assisting filling method includes: dissolving the energy-absorbing substance in a selected solvent to form an energy-absorbing substance solution, and the concentration of the energy-absorbing substance solution is 1 wt % to 60 wt %; The porous airgel material is contacted with the energy-absorbing substance solution, left to stand for 1 hour to 24 hours, the energy-absorbing substance on the surface is taken out and removed, and then dried to obtain an airgel-based energy-absorbing material.

Further, the process of solution-assisted filling specifically includes the following steps:

Dissolve the energy-absorbing substance in the selected solvent, soak the porous airgel material into the above energy-absorbing substance solution, let it stand for 1h to 24h, take out and remove the surface energy-absorbing substance solution, freeze-dry, vacuum-dry or dry under normal pressure After that, the airgel-based energy-absorbing material is obtained.

Further, the selected solvent includes, but is not limited to, any one or a combination of two or more of water, cyclohexane, ethanol, tert-butanol, acetone, tetrahydrofuran, ethyl acetate, and the like.

The airgel-based energy-absorbing material of the present invention can be prepared into any size and shape, and the structure can be designed, and the energy-absorbing material can get rid of the restrictions of creep and no fixed shape; and it can be cut and packaged according to different sizes Over irregular surfaces. At the same time, the preparation process is simple, the conditions are mild and controllable, and it is easy to realize large-scale production.

Another aspect of the embodiment of the present invention also provides the application of the aforementioned airgel-based energy-absorbing material in the fields of shock absorption and noise resistance, impact protection, energy absorption and the like.

In summary, with the above-mentioned technical solution, the airgel-based energy-absorbing material provided by the present invention is composed of a porous airgel matrix loaded with energy-absorbing substances and functional additives, and the porous airgel matrix is formed by overlapping nanofibers. It has a continuous three-dimensional porous network structure, with adjustable macrostructure, density, porosity, specific surface area, etc., and strong capillary force. The energy-absorbing substances and functional additives are adsorbed on the nanofiber surface and pores of the porous airgel matrix. The airgel-based energy-absorbing material has high energy absorption and high sensitivity, and has wide application prospects, and can be used in the fields of shock absorption and noise resistance, impact protection, energy absorption, and the like.

In order to make the object, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be described in further detail below in conjunction with several preferred embodiments and with reference to the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention. , not all embodiments, those skilled in the art can make adjustments according to actual conditions. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention. The test method of specific condition is not indicated in the following examples, and the test method in the embodiment is all carried out according to conventional conditions. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not constitute a conflict with each other.

Example 1

This embodiment provides an aramid airgel film-based energy-absorbing material, the preparation method of which comprises the following steps:

(1) Preparation of aramid airgel film: prepare 0.5wt% aramid nanofiber dispersion liquid, and prepare aramid airgel film by scraping method.

(2) Preparation of filling material: prepare a polyborosiloxane/absolute ethanol solution with a mass fraction of 30 wt%.

(3) Preparation of aramid airgel film-based energy-absorbing material: Put the aramid nanofiber airgel film in the aforementioned solution, take it out after standing for 12 hours, and remove the excess polyborosiloxane/absolute ethanol solution on the surface , and dried under normal pressure to obtain an airgel-based composite energy-absorbing film.

FIG. 2 is the thermogravimetric curve of the aramid airgel film-based energy-absorbing material obtained in Example 1. Please refer to Table 1 for other parameters.

Example 2

This embodiment provides an aramid airgel fiber-based energy-absorbing material, the preparation method of which comprises the following steps:

(1) Preparation of aramid airgel fiber: 10wt% aramid nanofiber dispersion liquid was prepared, and aramid airgel fiber was prepared by wet spinning method.

(2) Preparation of filling material: a polyborosiloxane/tert-butanol solution with a mass fraction of 60 wt % was prepared.

(3) Preparation of aramid airgel fiber-based energy-absorbing material: put the aramid nanofiber airgel fiber in the aforementioned solution, take it out after standing for 1 hour, and remove the excess polyborosiloxane/tert-butanol solution on the surface , and vacuum-dried to obtain airgel-based composite energy-absorbing fibers.

Fig. 3 is an infrared spectrogram of the aramid airgel fiber-based energy-absorbing material obtained in Example 2. Please refer to Table 1 for other parameters.

Example 3

This embodiment provides an aramid airgel honeycomb-based energy-absorbing material, the preparation method of which comprises the following steps:

(1) Preparation of aramid airgel honeycomb: prepare 5wt% aramid nanofiber dispersion liquid, and prepare aramid airgel honeycomb by template method.

(2) Preparation of filling materials: a plasticine/cyclohexane solution with a mass fraction of 10 wt % was prepared, and 5 wt % gold nanoparticles were added as functional additives.

(3) Preparation of aramid airgel honeycomb-based energy-absorbing material: place aramid nanofiber airgel honeycomb in the aforementioned solution, take it out after standing for 24 hours, remove excess filling liquid on the surface, and dry in vacuum to obtain aramid airgel. Gel-based composite energy-absorbing honeycomb.

Fig. 4 is an optical photo of the aramid airgel honeycomb-based energy-absorbing material obtained in Example 3. For other parameters, please refer to Table 1.

Example 4

This embodiment provides a cellulose airgel film-based energy-absorbing material, the preparation method of which comprises the following steps:

(1) Preparation of cellulose airgel film: prepare 0.1wt% cellulose nanofiber dispersion liquid, and prepare cellulose airgel film by doctor blade method.

(2) Preparation of filling material: prepare a polyborosiloxane/acetone solution with a mass fraction of 10 wt%, and add 10 wt% silica powder as a functional additive.

(3) Preparation of cellulose airgel film-based energy-absorbing material: Place the cellulose nanofiber airgel film in the aforementioned energy-absorbing material, take it out after standing for 8 hours, remove the excess material on the surface, and dry it in vacuum to obtain Airgel-based composite energy-absorbing films.

Figure 5 is an optical photo of the cellulose airgel film-based energy-absorbing material obtained in Example 4, and other parameters are shown in Table 1.

Example 5

This embodiment provides a 3D printing cellulose airgel three-dimensional lattice-based energy-absorbing material, and its preparation method includes the following steps:

(1) Preparation of 3D printed cellulose airgel three-dimensional lattice: prepare 2wt% cellulose nanofiber dispersion liquid, and use direct-writing 3D printing method to prepare 3D printed cellulose airgel three-dimensional lattice structure.

(2) Preparation of filling materials: prepolymer benzyl methacrylate monomer of soft and hard phase change materials, 1-hydroxycyclohexyl phenyl ketone photoinitiator, ethylene glycol dimethacrylate crosslinking agent, 1-Ethyl-3-methylimidazole bistrifluoromethanesulfonimide salt, 30wt% calcium carbonate powder, etc. were mixed uniformly.

(3) Preparation of 3D printed cellulose airgel three-dimensional lattice-based energy-absorbing material: place the 3D printed cellulose airgel three-dimensional lattice in the aforementioned mixed solution, take it out after standing for 6 hours, and remove excess substances on the surface, then The material was cured under ultraviolet light for 10 hours to obtain an airgel-based composite energy-absorbing material.

Figure 6 is an optical photo of the 3D printed cellulose airgel lattice-based energy-absorbing material obtained in Example 5, and other parameters are shown in Table 1.

Example 6

This embodiment provides a cellulose airgel block-based energy-absorbing material, the preparation method of which comprises the following steps:

(1) Preparation of cellulose airgel block: prepare 8wt% cellulose nanofiber dispersion liquid, and prepare cellulose airgel block by direct freeze-drying method.

(2) Preparation of filling material: chop nitrile rubber, prepare a nitrile rubber/ethyl acetate solution with a mass fraction of 10wt%, then add 1wt% graphene additive, and stir evenly.

(3) Preparation of cellulose airgel block-based energy-absorbing material: Place the cellulose nanofiber airgel block in the aforementioned mixed solution, take it out after standing for 1 hour, remove excess surface matter, wash, and then put The material was placed in an oven at 90°C for 15 hours to obtain an airgel-based composite energy-absorbing block.

Fig. 7 is the quasi-static stress-strain curve of the cellulose airgel block-based energy-absorbing material obtained in Example 6. Please refer to Table 1 for other parameters.

Example 7

This embodiment provides a polyimide airgel fiber-based energy-absorbing material, the preparation method of which comprises the following steps:

(1) Preparation of polyimide airgel fibers: polyimide airgel fibers with a solid content of 10 wt% were prepared by confined spinning method.

(2) Preparation of filling material: chop the natural rubber, and prepare a natural rubber/tetrahydrofuran solution with a mass fraction of 10 wt%.

(3) Preparation of polyimide airgel fiber-based energy-absorbing material: put the polyimide airgel fiber in the aforementioned mixed solution, take it out after standing for 6 hours, remove the excess substances on the surface, wash, and then put the material Place in an oven at 90°C for 15 hours to obtain an airgel-based composite energy-absorbing block.

FIG. 8 is a photo showing the flexibility of the polyimide airgel fiber-based energy-absorbing material obtained in Example 7. Please refer to Table 1 for other parameters.

Example 8

This embodiment provides a cellulose airgel fiber-based energy-absorbing material, the preparation method of which comprises the following steps:

(1) Preparation of cellulose airgel fibers: prepare 0.1wt% cellulose nanofiber dispersion liquid, and prepare cellulose airgel fibers by wet spinning method.

(2) Preparation of filling material: add sulfur vulcanizing agent and rosin acid soap emulsifier to chloroprene to prepare oil phase; prepare water and sodium hydroxide to form water phase; then emulsify oil phase and water phase , add n-dodecanethiol relative molecular weight regulator and potassium persulfate initiator solution, and stir the system in an ice bath at 4°C.

(3) Preparation of cellulose airgel fiber-based energy-absorbing material: Place the cellulose nanofiber airgel fiber in the aforementioned mixed solution, take it out after standing for 10 minutes, remove the excess material on the surface, and then place the material at 40°C After 3 hours in the environment, the temperature was lowered, and the airgel-based composite energy-absorbing fibers were obtained after chain termination, coagulation, washing, and drying under normal pressure.

FIG. 9 is the internal morphology of the cellulose airgel fiber-based energy-absorbing material obtained in Example 8. Please refer to Table 1 for other parameters.

Example 9

This embodiment provides a silk protein airgel film-based energy-absorbing material, the preparation method of which comprises the following steps:

(1) Preparation of silk protein airgel film: prepare 0.5wt% silk protein nanofiber dispersion liquid, and prepare silk protein airgel film by scraping method.

(2) Preparation of filling material: After preparing a polydimethylsiloxane/absolute ethanol solution with a mass fraction of 1 wt%, 1 wt% of carbon nanotubes were added.

(3) Preparation of silk protein airgel film-based energy-absorbing material: place the silk protein nanofiber airgel film in the aforementioned solution, take it out after standing for 12 hours, and remove excess polydimethylsiloxane/anhydrous polydimethylsiloxane on the surface ethanol solution and dried under normal pressure to obtain an airgel-based composite energy-absorbing film.

FIG. 10 is the high-speed impact curve of the silk protein airgel film-based energy-absorbing material obtained in Example 9. For other parameters, please refer to Table 1.

Example 10

This embodiment provides a silver nanowire airgel block-based energy-absorbing material, the preparation method of which comprises the following steps:

(1) Preparation of silver nanowire airgel block: prepare 10wt% silver nanowire dispersion liquid, and prepare silver nanowire airgel block by direct drying method.

(2) Preparation of filling material: Prepare a polydimethylsiloxane/absolute ethanol solution with a mass fraction of 20 wt%, and add 1 wt% transition metal nitride/carbide (Ti ₃ C ₂ T _x MXene).

(3) Preparation of silver nanowire airgel film-based energy-absorbing material: place the silver nanowire airgel film in the aforementioned solution, take it out after standing for 12 hours, and remove excess polydimethylsiloxane/anhydrous ethanol solution, followed by washing and freeze-drying to obtain an airgel-based composite energy-absorbing block.

FIG. 11 is the high-speed impact curve of the silver nanowire airgel block-based energy-absorbing material obtained in Example 10. Please refer to Table 1 for other parameters.

The energy absorption values of airgel-based energy-absorbing materials obtained in Table 1 Examples 1-10

Comparative example 1

This comparative example provides an aramid airgel film material. Compared with Example 1, this comparative example does not add polyborosiloxane/absolute ethanol solution. The energy absorption value of the obtained material is 30J/g.

Through Examples 1-10, it can be found that the airgel-based energy-absorbing material obtained by the above-mentioned technical solution of the present invention has excellent properties such as designable structure, high loading capacity, excellent energy-absorbing effect, and simple process.

In addition, the inventors of this case also conducted experiments with other raw materials and conditions listed in this specification with reference to the methods of Examples 1-10, and similarly produced a compound with designable structure, high loading capacity, excellent energy absorption effect, and wide application. Airgel-based energy-absorbing materials.

Although the present invention has been described with reference to illustrative embodiments, it will be understood by those skilled in the art that various other changes, omissions and/or additions may be made without departing from the spirit and scope of the invention and that substantial, etc. Effects replace elements of the described embodiments. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from its scope. Therefore, it is not intended that the invention be limited to the particular embodiments disclosed for carrying out this invention, but that the invention will include all embodiments falling within the scope of the appended claims.

Claims (10)

1. An airgel-based energy-absorbing material, characterized in that it comprises: A porous airgel material as a substrate, which includes a connected three-dimensional porous network structure formed by overlapping nanofibers; And, the energy-absorbing substances loaded in the porous airgel material and the functional additives selectively added or not added, the energy-absorbing substances and functional additives are wrapped on the nanofibers and embedded and filled in the three-dimensional porous In the network structure, wherein, the energy-absorbing substance includes any one of polydimethylsiloxane, polyborosiloxane, soft and hard phase change materials, plasticine, natural rubber, neoprene, and nitrile rubber or a combination of two or more. 2. The airgel-based energy-absorbing material according to claim 1, wherein the nanofibers include aramid nanofibers, cellulose nanofibers, polyimide nanofibers, silk protein nanofibers, silver nanofibers, Any one or a combination of two or more fibers; And/or, the macroscopic structure of the porous airgel material includes any one or a combination of two or more of honeycomb, Pondez-shaped, three-dimensional lattice, film, fiber, and block; And/or, the interior of the porous airgel material has a hierarchical porous network structure, and the hierarchical porous network structure consists of micropores with a pore diameter of 2 nm or less, mesopores with a pore diameter of 2 nm to 50 nm, and large pores with a pore diameter of 50 nm to 10 cm. Pore composition, the porous airgel material has a porosity of 50-99.99%, a density of 0.1-1500 mg/cm ³ , a specific surface area of 50-2500 m ² /g, and a pore volume of 0.1-15 cm ³ /g. 3. The airgel-based energy-absorbing material according to claim 1, characterized in that: the content of energy-absorbing substances in the airgel-based energy-absorbing material is 30wt% to 99wt%; and/or, the air The content of functional additives in the gel-based energy-absorbing material is 0wt% to 30wt%; and/or, the functional additives include calcium carbonate, carbon nanotubes, graphene, transition metal nitrides, transition metal carbides, metals, bismuth Any one or a combination of two or more of the silicon oxide particles. 4. The airgel-based energy-absorbing material according to claim 1, characterized in that: the energy-absorbing value of the airgel-based energy-absorbing material is 0.1-1000 J/g. 5. The preparation method of the airgel-based energy-absorbing material according to any one of claims 1-4, characterized in that, comprising: Provide porous airgel materials; By means of in-situ polymerization or solution-assisted filling, the energy-absorbing material and selectively added or not added functional additives are filled into the porous airgel material, and then dried to obtain the airgel-based energy-absorbing material. 6. The preparation method according to claim 5, comprising: at least using wet spinning method, confined sol-gel reaction spinning method, freeze-dry spinning method, template method, 3D printing method, scraping method, etc. The porous airgel material can be prepared by any one or a combination of coating methods. 7. The preparation method according to claim 5, characterized in that it comprises: placing the energy-absorbing material prepolymer in the reaction vessel, and making it contact with the porous airgel material, standing for 1h-24h, taking out And remove the excess energy-absorbing material prepolymer on the surface, then in-situ polymerize the energy-absorbing material prepolymer, and then dry it to prepare an airgel-based energy-absorbing material; Preferably, the energy-absorbing material prepolymer includes an energy-absorbing material precursor, an initiator, a crosslinking agent and an ionic liquid, or, the energy-absorbing material prepolymer includes an energy-absorbing material precursor, an emulsifier, an initiator , relative molecular weight modifiers, vulcanizing agents and solvents. 8. The preparation method according to claim 5, characterized in that, comprising: dissolving the energy-absorbing substance in a selected solvent to form an energy-absorbing substance solution, and making the porous airgel material and the energy-absorbing substance After contacting the solution, let it stand for 1h to 24h, take out and remove the energy-absorbing substance on the surface, and then dry it to obtain an airgel-based energy-absorbing material; Preferably, the energy-absorbing substance solution has a concentration of 1 wt% to 60 wt%; Preferably, the selected solvent includes any one or a combination of two or more of water, cyclohexane, ethanol, tert-butanol, acetone, tetrahydrofuran, and ethyl acetate. 9. The preparation method according to claim 5, characterized in that: said drying comprises at least any one of freeze drying, vacuum drying or normal pressure drying. 10. The application of the airgel-based energy-absorbing material according to any one of claims 1-4 in the field of shock absorption and anti-noise, impact protection or energy absorption.

Images