Boron-containing fuel, preparation method thereof and propellant

Abstract

The invention provides a boron-containing fuel, a preparation method thereof and a propellant. The boron-containing fuel includes: boron particles; the bonding layer is used for coating at least part of the surfaces of the boron particles; the hydrophobic structures are in a chain shape, and the first ends of the hydrophobic structures are connected with the bonding layer. The bonding layers are arranged on the surfaces of at least part of the boron particles, so that agglomeration of the boron particles is prevented, and agglomeration of the boron particles and sintering of products in the combustion process are reduced; meanwhile, boron oxide on the surfaces of the particles can be continuously removed through the arrangement of the hydrophobic structures, more complete combustion is achieved, and therefore the combustion performance of the boron particles is improved.

Description

Technical Field

[0001] This application relates to the technical field of fuels, and particularly to boron-containing fuels, their preparation methods, and propellants. Background Art

[0002] Boron is an important solid fuel and energetic additive. It has the third-highest mass calorific value (58.7 MJ / kg) in nature and the highest mass calorific value (137.5 MJ / L). The complete oxide (B 2 O 3 ) produced during the combustion of boron has a low melting point (727 K) and a high boiling point (2350 K). However, boron exists in a liquid form during the combustion process, which inhibits the further oxidation of boron, resulting in low combustion efficiency. At the same time, it also has the disadvantage of a high ignition temperature. Based on this, the present invention is proposed. Summary of the Invention

[0003] In view of this, embodiments of this application provide a boron-containing fuel, its preparation method, and a propellant.

[0004] The first aspect of this application provides a boron-containing fuel, comprising:

[0005] Boron particles;

[0006] An adhesive layer that coats at least part of the surface of the boron particles;

[0007] Multiple hydrophobic structures that are chain-shaped, and a first end of the hydrophobic structure is connected to the adhesive layer.

[0008] In one embodiment, the surface of the adhesive layer includes hydroxyl groups;

[0009] Preferably, the raw materials for forming the adhesive layer include chitosan and / or aminocellulose.

[0010] In one embodiment, a second end of the hydrophobic structure is a free end, and the first end is disposed opposite to the second end;

[0011] Preferably, the hydrophobic structure includes fluorine elements;

[0012] Preferably, the mass of the fluorine element accounts for 1%-15% of the mass of the boron-containing fuel;

[0013] Preferably, the raw materials for forming the hydrophobic structure include fluorosilanes;

[0014] Preferably, the raw materials for forming the hydrophobic structure include perfluorosilanes;

[0015] Preferably, the perfluorosilane includes 1H,1H,2H,2H-perfluorodecyltriethoxysilane,

[0016] 1H,1H,2H,2H-Perfluorodecyltrichlorosilane, 1H,1H,2H,2H-perfluorooctyltriethoxysilane, 1H,1H,2H,2H-perfluorooctyltrichlorosilane, 1H,1H,2H,2H-perfluorohexyltriethoxysilane,

[0017] at least one of 1H,1H,2H,2H-perfluorohexyltrichlorosilane, 3,3,3-trifluoropropyltrimethoxysilane, trifluorobutyltrichlorosilane, perfluoropropyltrichlorosilane and 3,3,3-trifluoropropyltrichlorosilane.

[0018] In one embodiment, the boron particles include amorphous boron particles;

[0019] Preferably, the particle size of the boron particles is 50 - 80 nm.

[0020] In one embodiment, the boron-containing fuel includes components with the following mass percentages:

[0021] 60 - 70 wt% of the boron particles, 10 - 20 wt% of the hydrophobic structure, and the balance of the adhesive layer.

[0022] In one embodiment, the ignition temperature of the boron-containing fuel is less than or equal to 500 °C;

[0023] Preferably, under the conditions of a pressure of 3 Mpa and an oxygen atmosphere, the combustion heat of the boron-containing fuel is greater than or equal to 28 MJ / kg, and the peak combustion pressure is greater than or equal to 5 Mpa.

[0024] The second aspect of the present application provides a preparation method of the boron-containing fuel described above, including:

[0025] Preparing an adhesive layer on at least part of the surface of the boron particles;

[0026] Connecting one end of a plurality of hydrophobic structures in a chain shape to the adhesive layer.

[0027] In one embodiment, a droplet microfluidics technique is used to prepare an adhesive layer on at least part of the surface of the boron particles;

[0028] Preferably, preparing an adhesive layer on at least part of the surface of the boron particles includes:

[0029] Dispersing the boron particles into a solution containing the raw materials of the adhesive layer to obtain a dispersed phase solution;

[0030] Mixing at least one of n-octanol, n-octane, n-heptanol and n-heptane with Span-80 to obtain a continuous phase solution;

[0031] Feeding the dispersed phase solution and the continuous phase solution into a cross-droplet microfluidic device respectively to obtain dispersed droplets;

[0032] Preferably, the flow rate of introducing the dispersed phase solution into the cross-droplet microfluidic device is 4-6 μm / min, and / or the flow rate of introducing the continuous phase solution into the cross-droplet microfluidic device is 18-22 μm / min;

[0033] Preferably, connecting one end of a plurality of chain-shaped hydrophobic structures to the adhesive layer includes:

[0034] Mixing span-80 and n-octanol solution to obtain a mixed solution;

[0035] Dispersing at least one of succinaldehyde, glutaraldehyde, adipaldehyde, pimelaldehyde, and terephthalaldehyde and perfluorosilane into the mixed solution to obtain a receiving phase solution;

[0036] Mixing the dispersed droplets with the receiving phase solution, and obtaining the boron-containing fuel after the first reaction;

[0037] Preferably, the temperature of the first reaction is 50-70 °C and the time is 10-20 h.

[0038] In one embodiment,

[0039] Using droplet microfluidics technology to prepare an adhesive layer on at least part of the surface of boron particles;

[0040] Preferably, preparing an adhesive layer on at least part of the surface of boron particles includes:

[0041] Dispersing boron particles into a solution containing the raw materials of the adhesive layer to obtain a dispersed phase solution;

[0042] Mixing at least one of n-octanol, n-octane, n-heptanol, and n-heptane with span-80 to obtain a continuous phase solution;

[0043] Mixing at least one of succinaldehyde, glutaraldehyde, adipaldehyde, pimelaldehyde, and terephthalaldehyde, span-80, and n-octanol to obtain a receiving phase solution;

[0044] Respectively introducing the dispersed phase solution and the continuous phase solution into a cross-droplet microfluidic device to obtain dispersed droplets;

[0045] Dispersing the dispersed droplets into the receiving phase solution, and obtaining dispersed particles after the second reaction;

[0046] Preferably, dispersing boron particles into a solution containing the raw materials of the adhesive layer includes: dispersing boron particles into a solution containing acetic acid and the raw materials of the adhesive layer;

[0047] Preferably, the flow rate of introducing the dispersed phase solution into the cross-droplet microfluidic device is 4-6 μm / min, and / or the flow rate of introducing the continuous phase solution into the cross-droplet microfluidic device is 18-22 μm / min;

[0048] Preferably, connecting one end of a plurality of chain-shaped hydrophobic structures to the adhesive layer includes:

[0049] Mixing the dispersed particles with a solution containing perfluorosilane, and obtaining the boron-containing fuel after a third reaction;

[0050] Preferably, the temperature of the third reaction is 50-70 °C and the time is 10-20 h.

[0051] The third aspect of the present application provides a propellant including the boron-containing fuel described above.

[0052] According to the boron-containing fuel provided by the embodiments of the present application, an adhesive layer is provided on the surface of at least part of the boron particles, which is beneficial to preventing the aggregation of boron particles and reducing the aggregation of boron particles and the sintering of products during combustion; meanwhile, the setting of the hydrophobic structure can continuously remove boron oxide on the particle surface, realizing more complete combustion, thereby improving the combustion performance of boron particles; moreover, the boron-containing fuel of the present application can achieve continuous and stable production and is suitable for large-scale application. Description of the Drawings

[0053] Figure 1 It is a schematic structural diagram of the boron-containing fuel in an embodiment of the present application.

[0054] Figure 2 It is a schematic structural diagram of preparing a dispersion droplet by using a microfluidic device in an embodiment of the present application.

[0055] Figure 3 It is a contact angle result diagram of the boron-containing fuels of Example 1, Example 3, Example 4 and Comparative Example 2. Detailed Embodiments

[0056] Next, the technical solutions in the embodiments of the present application will be clearly and completely described in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without making creative efforts shall fall within the protection scope of the present application.

[0057] In addition, to better illustrate the present application, numerous specific details are provided in the following detailed implementation manners. Those skilled in the art should understand that the present application can also be implemented without certain specific details. In some instances, methods and means well-known to those skilled in the art are not described in detail in order to highlight the gist of the present application.

[0058] It should be noted that similar reference numerals and letters denote similar items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings.

[0059] In addition, terms such as "first" and "second" are used for descriptive distinction only and cannot be construed as indicating or implying relative importance.

[0060] The first aspect of the present application provides a boron-containing fuel. Referring to Figure 1 the structural schematic diagram of the boron-containing fuel shown, the boron-containing fuel includes: boron particles 100, an adhesive layer 200, and a plurality of hydrophobic structures 300; the adhesive layer 200 coats at least a part of the surface of the boron particles 100; the hydrophobic structures 300 are chain-shaped, and a first end 310 of the hydrophobic structure 300 is connected to the adhesive layer 200.

[0061] According to the boron-containing fuel provided by the embodiments of the present application, an adhesive layer is provided on the surface of at least a part of the boron particles, which is beneficial to preventing the aggregation of boron particles and reducing the aggregation of boron particles and the sintering of products during combustion; at the same time, the setting of the hydrophobic structure can continuously remove boron oxide on the particle surface to achieve more complete combustion, thereby improving the combustion performance of boron particles; moreover, the boron-containing fuel of the present invention can achieve continuous and stable production and is suitable for large-scale application.

[0062] It can be understood that the boron particles can be regular spherical, elliptical or other shapes, or can be irregular shapes.

[0063] Exemplarily, the boron particles include amorphous boron particles.

[0064] In one embodiment, the particle size of the boron particles is 50 - 80 nm, for example, it can be 50 nm, 60 nm, 70 nm or 80 nm, etc. Thus, the size of the boron particles is appropriate and the specific surface area is relatively large, which is beneficial to achieving full combustion.

[0065] In one embodiment, the surface of the adhesive layer includes hydroxyl groups; for example, the raw materials for forming the adhesive layer include chitosan and / or amino cellulose. Thus, the surface of the adhesive layer formed by chitosan has abundant hydroxyl groups, which is beneficial to connecting with the hydrophobic structure.

[0066] In one embodiment, referring to Figure 1, the second end 320 of the hydrophobic structure 300 is a free end, and the first end 310 is disposed opposite to the second end 320. Thus, during the preparation process, it is beneficial to achieve uniform distribution of the hydrophobic structure on the surface of the adhesive layer.

[0067] In one embodiment, the hydrophobic structure includes fluorine element; the presence of fluorine can continuously remove boron oxide on the surface of boron particles, achieve more complete combustion, and thus improve the combustion performance of boron particles. For example, the raw material for forming the hydrophobic structure includes fluorosilane. Preferably, the raw material for forming the hydrophobic structure includes perfluorosilane. Commonly used fluorine-containing materials (such as polytetrafluoroethylene, polyvinylidene fluoride, fluorinated graphene, etc.) are generally mixed with boron particles by physical mixing method, and there are problems such as uneven size and particle agglomeration in applications. Compared with the above fluorine-containing materials, perfluorosilane is easily substituted and can complete graft modification under mild conditions to improve material properties.

[0068] In one embodiment, the mass of the fluorine element accounts for 1%-15% of the mass of the boron-containing fuel, for example, it can be 1%, 3%, 5%, 7%, 9%, 11%, 13% or 15%, etc. When the content of the fluorine element is appropriate, the effect of removing boron oxide on the surface of boron particles during the combustion process is excellent, which is beneficial to achieve more complete combustion. Compared with the above content range, when the content of the fluorine element is less than 1%, the boron-containing fuel burns incompletely and the combustion heat decreases; when the content of the fluorine element is higher than 15%, the relative content of boron in the boron-containing fuel decreases and the combustion heat decreases.

[0069] Optionally, the perfluorosilane includes at least one of 1H,1H,2H,2H-perfluorodecyltriethoxysilane,

[0070] 1H,1H,2H,2H-perfluorodecyltrichlorosilane, 1H,1H,2H,2H-perfluorooctyltriethoxysilane, 1H,1H,2H,2H-perfluorooctyltrichlorosilane, 1H,1H,2H,2H-perfluorohexyltriethoxysilane,

[0071] 1H,1H,2H,2H-perfluorohexyltrichlorosilane, 3,3,3-trifluoropropyltrimethoxysilane, trifluorobutyltrichlorosilane, perfluoropropyltrichlorosilane and 3,3,3-trifluoropropyltrichlorosilane.

[0072] Exemplarily, taking the connection of the first end of 1H,1H,2H,2H-perfluorodecyltriethoxysilane to the adhesive layer as an example for illustration, the structural formula of 1H,1H,2H,2H-perfluorodecyltriethoxysilane is The first end of 1H,1H,2H,2H-perfluorodecyltriethoxysilane is the end containing silicon element. During the grafting process of 1H,1H,2H,2H-perfluorodecyltriethoxysilane and the adhesive layer, one ethoxy group in 1H,1H,2H,2H-perfluorodecyltriethoxysilane is replaced by the hydroxyl group on the surface of the adhesive layer, thereby realizing the connection between the first end of 1H,1H,2H,2H-perfluorodecyltriethoxysilane and the adhesive layer.

[0073] In the boron-containing fuel of the embodiment of the present application, chitosan wraps the nano boron particles as the adhesive layer, which can effectively solve the problem of boron particle agglomeration; the hydroxyl groups on the surface of chitosan can attack the silicon atom in perfluorosilane to carry out substitution reaction, realizing the grafting of perfluorosilane. Perfluorosilane can not only be used as a combustion promoter, but also provide surface hydrophobic properties for the boron-containing fuel, which is more conducive to preservation. During the combustion process, chitosan and perfluorosilane will release a large amount of gas to trigger microexplosions to disperse the nano boron particles. The gaseous fluoride produced by the combustion of perfluorosilane can also carry out pre-ignition reaction with boron particles, turning boron oxide on the surface of boron particles into gaseous BF 3 and BOF, thereby promoting mass transfer with oxygen, reducing the ignition temperature and promoting the complete release of the energy of boron particles, and significantly improving the combustion performance of boron particles. It should be noted that the above takes chitosan as the raw material of the adhesive layer and perfluorosilane as the raw material of the hydrophobic structure as an example to explain the specific process of the combustion of boron-containing fuel. The specific process of the combustion of boron-containing fuel with an adhesive layer of other types of raw materials and a hydrophobic structure of other types of raw materials can refer to the above description, and will not be elaborated here.

[0074] In one embodiment, the boron-containing fuel includes components with the following mass percentages: the boron particles 60-70 wt% (for example, it can be 60 wt%, 62 wt%, 64 wt%, 66 wt%, 68 wt% or 70 wt% etc.), the hydrophobic structure 10-20 wt% (for example, it can be 10 wt%, 12 wt%, 14 wt%, 16 wt%, 18 wt% or 20 wt% etc.), and the balance of the adhesive layer. Compared with the above content range, when the content of boron particles is lower than 60 wt%, the theoretical combustion calorific value decreases; when the content of boron particles is higher than 70 wt%, it is easy to burn incompletely; when the content of the hydrophobic structure is lower than 10 wt%, it leads to incomplete combustion, and when the content of the hydrophobic structure is higher than 20 wt%, the theoretical combustion calorific value decreases.

[0075] In one embodiment, the ignition temperature of the boron-containing fuel is less than or equal to 500 °C; under the conditions of a pressure of 3 Mpa and an oxygen atmosphere, the combustion heat of the boron-containing fuel is greater than or equal to 28 MJ / kg, and the peak combustion pressure is greater than or equal to 5 Mpa.

[0076] The second aspect of the present application provides a method for preparing the aforementioned boron-containing fuel, including the following steps.

[0077] S100: Prepare an adhesive layer on at least part of the surface of boron particles.

[0078] In one embodiment, the adhesive layer is prepared on at least part of the surface of boron particles by using droplet microfluidics technology.

[0079] In one embodiment, preparing the adhesive layer on at least part of the surface of boron particles includes the following steps.

[0080] S110: Disperse boron particles into a solution containing the raw materials of the adhesive layer to obtain a dispersed-phase solution.

[0081] Exemplarily, in the dispersed-phase solution, the content of boron particles is 4-6 wt%, and the content of the raw materials of the adhesive layer is 0.5-1 wt%.

[0082] Exemplarily, the solution containing the raw materials of the adhesive layer is an aqueous solution containing the raw materials of the adhesive layer.

[0083] Exemplarily, the raw materials of the adhesive layer include chitosan and / or aminocellulose.

[0084] Optionally, dispersing boron particles into a solution containing the raw materials of the adhesive layer includes: dispersing boron particles into a solution containing acetic acid and the raw materials of the adhesive layer. Acetic acid is beneficial to promoting the dissolution of the raw materials of the adhesive layer.

[0085] S120: Mix at least one of n-octanol, n-octane, n-heptanol, and n-heptane with Span-80 to obtain a continuous-phase solution.

[0086] Exemplarily, in the continuous-phase solution, the content of Span-80 is 1-2 wt%.

[0087] S130: Respectively introduce the dispersed-phase solution and the continuous-phase solution into a cross-droplet microfluidic device to obtain dispersed droplets.

[0088] Optionally, the flow rate of introducing the dispersed-phase solution into the cross-droplet microfluidic device is 4-6 μm / min (for example, it can be 4 μm / min, 5 μm / min, or 6 μm / min, etc.), and / or the flow rate of introducing the continuous-phase solution into the cross-droplet microfluidic device is 18-22 μm / min (for example, it can be 18 μm / min, 20 μm / min, or 22 μm / min, etc.).

[0089] S200: Connect one end of a plurality of hydrophobic structures in a chain shape to the adhesive layer.

[0090] In one embodiment, connecting one end of a plurality of chain-shaped hydrophobic structures to the adhesive layer includes the following steps.

[0091] S210: Mix Span-80 and n-octanol solution to obtain a mixed solution.

[0092] S220: Disperse at least one of succinaldehyde, glutaraldehyde, adipaldehyde, pimelaldehyde and terephthalaldehyde and perfluorosilane into the mixed solution to obtain a receiving phase solution.

[0093] S230: Mix the dispersed liquid droplets with the receiving phase solution, and obtain the boron-containing fuel after reaction.

[0094] Exemplarily, the temperature of the reaction is 50-70 °C (for example, it can be 50 °C, 60 °C or 70 °C, etc.), and the time is 10-20 h (for example, it can be 10 h, 12 h, 15 h, 18 h or 20 h, etc.).

[0095] It can be understood that the above preparation method is a continuous preparation method, that is, the obtained liquid dispersed liquid droplets are directly mixed with the receiving phase solution containing perfluorosilane, and the content of hydrophobic structures in the prepared boron-containing fuel is relatively high and the dispersion is more uniform.

[0096] In another embodiment, a droplet microfluidics technique is used to prepare an adhesive layer on at least a part of the surface of boron particles. Exemplarily, preparing an adhesive layer on at least a part of the surface of boron particles includes: dispersing boron particles into a solution containing raw materials of the adhesive layer to obtain a dispersed phase solution; mixing at least one of n-octanol, n-octane, n-heptanol and n-heptane with Span-80 to obtain a continuous phase solution; mixing at least one of succinaldehyde, glutaraldehyde, adipaldehyde, pimelaldehyde and terephthalaldehyde, Span-80 and n-octanol to obtain a receiving phase solution; respectively introducing the dispersed phase solution and the continuous phase solution into a cross-droplet microfluidic device to obtain dispersed liquid droplets; dispersing the dispersed liquid droplets into the receiving phase solution, and obtaining dispersed particles after a second reaction. Thus, in this embodiment, solid dispersed particles are first obtained, and then subsequent hydrophobic structures are prepared.

[0097] Exemplarily, connecting one end of a plurality of chain-shaped hydrophobic structures to the adhesive layer includes: mixing the dispersed particles with a solution containing perfluorosilane, and obtaining the boron-containing fuel after a third reaction.

[0098] Optionally, dispersing boron particles into a solution containing raw materials of the adhesive layer includes: dispersing boron particles into a solution containing acetic acid and raw materials of the adhesive layer.

[0099] Optionally, the flow rate of introducing the dispersed phase solution into the cross-shaped droplet microfluidic device is 4 - 6 μm / min, and / or the flow rate of introducing the continuous phase solution into the cross-shaped droplet microfluidic device is 18 - 22 μm / min;

[0100] Optionally, the temperature of the third reaction is 50 - 70 °C, and the time is 10 - 20 h.

[0101] The third aspect of the present application provides a propellant, including the boron-containing fuel described above.

[0102] It can be understood that the propellant can be used in aerospace vehicles, such as airplanes, etc.

[0103] The following further elaborates on the present application in conjunction with specific embodiments. It should be noted that the following embodiments are only used to explain the present application and should not be construed as a limitation to the present application.

[0104] Example 1

[0105] The preparation method of the boron-containing fuel includes the following steps:

[0106] (1) Add 0.75 g of chitosan and 1.5 g of acetic acid to 100 g of deionized water, stir and dissolve, then add 5 g of nano-boron powder (particle size 60 - 80 nm), and ultrasonically disperse it evenly for 2 h to be used as the dispersed phase; add 2 g of span-80 to 100 g of n-octanol, stir and dissolve, to be used as the continuous phase; add 5 g of an n-octanol solution of glutaraldehyde with a mass concentration of 0.5% to the n-octanol solution of 2 wt% span-80, and stir evenly to be used as the receiving phase.

[0107] (2) As Figure 2 shown, use an injection pump to inject the dispersed phase into the microfluidic device at a flow rate of 5 μm / min, use an injection pump to inject the continuous phase into the microfluidic device at a flow rate of 20 μm / min, obtain droplets with uniform size through the shearing action of the continuous phase on the dispersed phase, and after the droplets enter the receiving phase, they are crosslinked and cured after 12 h of stirring reaction, and then obtain monodisperse fuel microcapsules through centrifugation, washing, and drying.

[0108] (3) Put 0.2 g of the monodisperse fuel microcapsules prepared in step (2) into an ethanol solution of perfluorodecyltriethoxysilane with a mass concentration of 50%, stir and react at 60 °C for 12 h, and then obtain the boron-containing fuel through centrifugation, washing, and drying.

[0109] In the boron-containing fuel of this example, the content of the hydrophobic structure is 15%.

[0110] Example 2

[0111] The preparation method of the boron-containing fuel includes the following steps:

[0112] (1) Add 0.75 g of chitosan and 1.5 g of acetic acid to 100 g of deionized water, stir and dissolve, then add 5 g of nano boron powder (particle size 60 - 80 nm), and ultrasonicate for 2 h to disperse it evenly, which is used as the dispersed phase; add 2 g of span - 80 to 100 g of n - octanol, stir and dissolve, which is used as the continuous phase; add 5 g of an n - octanol solution of glutaraldehyde with a mass concentration of 0.5% and 0.5 g of perfluorodecyltriethoxysilane to the n - octanol solution of 2 wt% span - 80, stir evenly, which is used as the receiving phase.

[0113] (2) As Figure 2 shown, use an injection pump to inject the dispersed phase into the microfluidic device at a flow rate of 5 μm / min, use an injection pump to inject the continuous phase into the microfluidic device at a flow rate of 20 μm / min, and obtain uniformly sized droplets through the shearing action of the continuous phase on the dispersed phase. After the droplets enter the receiving phase, they are cross - linked and cured after 12 h of stirring reaction, and then monodisperse fuel microcapsules are obtained through centrifugation, washing, and drying.

[0114] In the boron - containing fuel of this example, the content of the hydrophobic structure is 18%.

[0115] Example 3

[0116] The preparation method of the boron - containing fuel is basically the same as that of Example 2, except that perfluorodecyltriethoxysilane in the receiving phase is replaced by perfluorohexyltriethoxysilane.

[0117] In the boron - containing fuel of this example, the content of the hydrophobic structure is 13%.

[0118] Example 4

[0119] The preparation method of the boron - containing fuel is basically the same as that of Example 2, except that perfluorodecyltriethoxysilane in the receiving phase is replaced by 3 - trifluoropropyltrimethoxysilane.

[0120] In the boron - containing fuel of this example, the content of the hydrophobic structure is 10%.

[0121] Example 5

[0122] The preparation method of the boron - containing fuel is basically the same as that of Example 2, except that perfluorodecyltriethoxysilane in the receiving phase is replaced by perfluorodecyltrichlorosilane.

[0123] In the boron - containing fuel of this example, the content of the hydrophobic structure is 20%.

[0124] Example 6

[0125] The preparation method of the boron-containing fuel is basically the same as that of Example 2, except that perfluorodecyltriethoxysilane in the receiving phase is replaced by perfluorooctyltrichlorosilane.

[0126] In the boron-containing fuel of this example, the content of the hydrophobic structure is 17%.

[0127] Example 7

[0128] The preparation method of the boron-containing fuel is basically the same as that of Example 2, except that perfluorodecyltriethoxysilane in the receiving phase is replaced by perfluorohexyltrichlorosilane.

[0129] In the boron-containing fuel of this example, the content of the hydrophobic structure is 16%.

[0130] Example 8

[0131] The preparation method of the boron-containing fuel is basically the same as that of Example 2, except that perfluorodecyltriethoxysilane in the receiving phase is replaced by trifluorobutyltrichlorosilane.

[0132] In the boron-containing fuel of this example, the content of the hydrophobic structure is 12%.

[0133] Example 9

[0134] The preparation method of the boron-containing fuel is basically the same as that of Example 2, except that perfluorodecyltriethoxysilane in the receiving phase is replaced by perfluoropropyltrichlorosilane.

[0135] In the boron-containing fuel of this example, the content of the hydrophobic structure is 11%.

[0136] Example 10

[0137] The preparation method of the boron-containing fuel is basically the same as that of Example 2, except that perfluorodecyltriethoxysilane in the receiving phase is replaced by perfluorooctyltriethoxysilane.

[0138] In the boron-containing fuel of this example, the content of the hydrophobic structure is 14%.

[0139] Example 11

[0140] The preparation method of the boron-containing fuel is basically the same as that of Example 1, except that the content of the hydrophobic structure in the boron-containing fuel is 5 wt%.

[0141] Example 12

[0142] The preparation method of the boron-containing fuel is basically the same as that of Example 1, except that the content of the hydrophobic structure in the boron-containing fuel is 25 wt%.

[0143] Comparative Example 1

[0144] The fuel is nB (particle size: 60 - 80 nm).

[0145] Comparative Example 2

[0146] The preparation method of the boron-containing fuel is basically the same as that of Example 1, except that the operation of step (3) is not carried out.

[0147] Comparative Example 3

[0148] The preparation method of the boron-containing fuel includes:

[0149] 2 wt% of polyvinylidene fluoride and 8 wt% of boron particles are uniformly dispersed in ethyl acetate, and the solvent is evaporated to dryness while stirring to obtain a boron-containing fuel with a hydrophobic structure content of 20%.

[0150] Comparative Example 4

[0151] The preparation method of the boron-containing fuel includes:

[0152] Polytetrafluoroethylene and boron particles are put into a ball mill according to a mass ratio of 1:4 and sufficiently ground and mixed to obtain a boron-containing fuel with a hydrophobic structure content of 20%.

[0153] Ignition temperature test: 5 mg of the fuels of Examples 1-11 and Comparative Examples 1-4 are respectively taken, and the thermal properties of the samples are tested by a TG-DSC (thermogravimetry-differential scanning calorimetry) comprehensive thermal analyzer at a heating rate of 10 °C / min in an air atmosphere. The test temperature is from room temperature to 1000 °C, and the initial oxidation temperature of the samples is determined by the tangent method.

[0154] Constant volume combustion and combustion calorific value test: 0.2 g of fuel (the fuels include the fuels of Examples 1-11 and Comparative Examples 1-4 respectively) is used to test the combustion calorific value of the samples by a constant volume combustion device in an oxygen atmosphere of 3 MPa, and the pressure change during the combustion process is collected at the same time.

[0155] The initial oxidation temperatures, combustion calorific values and pressure peaks of the fuels obtained in Examples 1-12 and the fuels of Comparative Examples 1-4 are shown in Table 1.

[0156] Table 1

[0157] Sample Combustion heat (kJ / g) Peak pressure (kPa) Ignition temperature (°C) Example 1 29.4 5239.1 463.6 Example 2 30.6 5574.2 439.2 Example 3 29.2 5154.2 490.2 Example 4 28.5 4956.1 501.2 Example 5 31.2 5747.2 432.5 Example 6 30.2 5463.2 442.3 Example 7 29.7 5348.9 456.4 Example 8 29.0 5081.2 495.7 Example 9 28.7 5007.3 498.3 Example 10 29.2 5173.4 485.4 Example 11 28.2 4853.4 527.7 Example 12 26.3 5572.3 488.6 Comparative Example 1 13.9 3646.8 577.4 Comparative Example 2 27.5 4570.1 564.7 Comparative Example 3 26.5 5023.7 510.2 Comparative Example 4 29.4 5321.5 489.3

[0158] The water contact angles of the boron-containing fuels of Example 1, Example 3, Example 4 and Comparative Example 2 are as Figure 3 shown. Among them, the water contact angle of the boron-containing fuel of Example 1 is 142.8°, the water contact angle of the boron-containing fuel of Example 3 is 128.5°, the water contact angle of the boron-containing fuel of Example 4 is 119.8°, and the water contact angle of the boron-containing fuel of Comparative Example 2 is 72.5°; it can be seen that the boron-containing fuels of the embodiments of the present application have a large water contact angle and excellent hydrophobic effect.

[0159] The basic principles of the present application have been described above in conjunction with specific embodiments. However, it should be noted that the advantages, benefits, effects, etc. mentioned in the present application are only examples and not limitations, and it cannot be considered that these advantages, benefits, effects, etc. are essential for each embodiment of the present application. In addition, the specific details disclosed above are only for the purposes of illustration and easy understanding, rather than limitations, and these details do not limit the present application to necessarily implement with the above specific details.

[0160] The above description has been given for purposes of illustration and description. In addition, this description is not intended to limit the embodiments of the present application to the forms disclosed herein. Although multiple example aspects and embodiments have been discussed above, those skilled in the art will recognize certain variations, modifications, alterations, additions, and sub - combinations thereof.

Claims

1. A boron-containing fuel, characterized in that: include: Boron particles; An adhesive layer, the adhesive layer covers at least a portion of the surface of the boron particles; A plurality of hydrophobic structures are in a chain shape, and a first end of the hydrophobic structure is connected to the adhesive layer.

2. The boron-containing fuel according to claim 1, characterized in that The surface of the bonding layer includes hydroxyl groups; Preferably, the raw materials for forming the adhesive layer include chitosan and / or aminocellulose.

3. The boron-containing fuel according to claim 1, characterized in that The second end of the hydrophobic structure is a free end, and the first end is arranged opposite to the second end; Preferably, the hydrophobic structure includes fluorine element; Preferably, the mass of the fluorine element accounts for 1%-15% of the mass of the boron-containing fuel; Preferably, the raw material for forming the hydrophobic structure includes fluorine-containing silane; Preferably, the raw material for forming the hydrophobic structure includes perfluorosilane; Preferably, the perfluorosilane includes at least one of 1H,1H,2H,2H-perfluorodecyltriethoxysilane, 1H,1H,2H,2H-perfluorodecyltrichlorosilane, 1H,1H,2H,2H-perfluorooctyltriethoxysilane, 1H,1H,2H,2H-perfluorooctyltrichlorosilane, 1H,1H,2H,2H-perfluorohexyltriethoxysilane, 1H,1H,2H,2H-perfluorohexyltrichlorosilane, 3,3,3-trifluoropropyltrimethoxysilane, trifluorobutyltrichlorosilane, perfluoropropyltrichlorosilane and 3,3,3-trifluoropropyltrichlorosilane.

4. The boron-containing fuel according to claim 1, characterized in that The boron particles include amorphous boron particles; Preferably, the particle size of the boron particles is 50-80 nm.

5. The boron-containing fuel according to claim 1, characterized in that The boron-containing fuel comprises components having the following mass percentages: The boron particles comprise 60-70 wt %, the hydrophobic structure comprises 10-20 wt %, and the balance is the bonding layer.

6. The boron-containing fuel according to claim 1, characterized in that The ignition temperature of the boron-containing fuel is less than or equal to 500°C; Preferably, under the conditions of a pressure of 3 MPa and an oxygen atmosphere, the combustion heat of the boron-containing fuel is greater than or equal to 28 MJ / kg, and the peak combustion pressure is greater than or equal to 5 MPa.

7. A method for preparing a boron-containing fuel according to any one of claims 1 to 6, characterized in that: include: forming a bonding layer on at least a portion of the surface of the boron particles; One ends of a plurality of chain-like hydrophobic structures are connected to the adhesive layer.

8. The preparation method according to claim 7, characterized in that: Using droplet microfluidics technology to prepare an adhesive layer on at least a portion of the surface of the boron particles; Preferably, preparing the bonding layer on at least a portion of the surface of the boron particles comprises: dispersing boron particles into a solution containing a raw material for an adhesive layer to obtain a dispersed phase solution; mixing at least one of n-octanol, n-octane, n-heptanol and n-heptane with Span-80 to obtain a continuous phase solution; The dispersed phase solution and the continuous phase solution are respectively introduced into a cross droplet microfluidic device to obtain dispersed droplets; Preferably, dispersing the boron particles into a solution containing a raw material for the adhesive layer comprises: dispersing the boron particles into a solution containing acetic acid and a raw material for the adhesive layer; Preferably, the flow rate of the dispersed phase solution into the cross droplet microfluidic device is 4 to 6 μm / min, and / or the flow rate of the continuous phase solution into the cross droplet microfluidic device is 18 to 22 μm / min; Preferably, connecting one end of the plurality of chain-shaped hydrophobic structures to the adhesive layer comprises: Mixing Span-80 and the n-octanol solution to obtain a mixed solution; Dispersing at least one of succinic dialdehyde, glutaraldehyde, adipaldehyde, heptanedialdehyde and terephthalaldehyde and perfluorosilane into the mixed solution to obtain a receiving phase solution; Mixing the dispersed droplets with the receiving phase solution to obtain the boron-containing fuel after a first reaction; Preferably, the temperature of the first reaction is 50-70°C and the time is 10-20 hours.

9. The preparation method according to claim 7, characterized in that: Using droplet microfluidics technology to prepare an adhesive layer on at least a portion of the surface of the boron particles; Preferably, preparing the bonding layer on at least a portion of the surface of the boron particles comprises: dispersing boron particles into a solution containing a raw material for an adhesive layer to obtain a dispersed phase solution; mixing at least one of n-octanol, n-octane, n-heptanol and n-heptane with Span-80 to obtain a continuous phase solution; Mixing at least one of succinic dialdehyde, glutaraldehyde, adipaldehyde, heptanedialdehyde and terephthalaldehyde with Span-80 and n-octanol to obtain a receiving phase solution; The dispersed phase solution and the continuous phase solution are respectively introduced into a cross droplet microfluidic device to obtain dispersed droplets; dispersing the dispersed liquid droplets into the receiving phase solution to obtain dispersed particles after a second reaction; Preferably, dispersing the boron particles into a solution containing a raw material for the adhesive layer comprises: dispersing the boron particles into a solution containing acetic acid and a raw material for the adhesive layer; Preferably, the flow rate of the dispersed phase solution into the cross droplet microfluidic device is 4 to 6 μm / min, and / or the flow rate of the continuous phase solution into the cross droplet microfluidic device is 18 to 22 μm / min; Preferably, connecting one end of the plurality of chain-shaped hydrophobic structures to the adhesive layer comprises: Mixing the dispersed particles with a solution containing perfluorosilane to obtain the boron-containing fuel after a third reaction; Preferably, the temperature of the third reaction is 50-70° C., and the time is 10-20 hours.

10. A propellant, characterized in that: The boron-containing fuel comprises the boron-containing fuel according to any one of claims 1 to 6.

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