A RDX explosive crystal and a method for preparing the explosive crystal.

Abstract

This invention discloses a RDX explosive crystal and its preparation method, relating to the field of energetic materials technology. The explosive particles have an overall size in the micrometer range and contain nanoscale microstructural features. The explosive is prepared by recrystallization, and the main preparation process includes: dissolving RDX raw material in an organic solvent; adding the RDX solution to an antisolvent under stirring conditions; and adding a crystallization additive during the crystallization process. After crystallization, the product is separated and dried to obtain RDX crystals with nanostructural units and micrometer-sized macroscopic particles. The RDX explosive crystals prepared by this method have a uniform morphology and spherical grains. This preparation method has a simple process flow and is easy to scale up. The obtained RDX explosive crystals have significant application value in the fields of initiating explosives, detonating charges, and micro-device loading.

Description

Technical Field

[0001] This invention relates to the field of energetic materials technology, and in particular to a RDX explosive crystal and a method for preparing the explosive crystal. Background Technology

[0002] RDX explosive belongs to the nitramine class of explosives, and its scientific name is cyclotrimethylenetrinitramine. Nano-explosives typically refer to explosives where the interfacial spacing between the oxidizer and fuel reaches the nanometer level, giving the explosive a huge specific surface area. This results in significant surface and small-size effects, making nano-explosives easy to initiate and propagate under high-pressure, short-pulse conditions, leading to a violent explosion. Therefore, nano-explosives are widely used in initiating explosives, detonating explosives, and micro-device charges.

[0003] However, traditional nano-explosives increase the reaction surface area by preparing explosives with nano-sized particles. Due to their high surface energy, these nano-sized nano-explosives are prone to particle agglomeration and maturation during use and long-term storage. This causes the nanoparticles to spontaneously approach and combine, resulting in larger particle size and reduced total surface area, which leads to a decrease in initiation and detonation performance. Summary of the Invention

[0004] The purpose of this invention is to address the problem that existing RDX nano-explosives are prone to particle agglomeration and maturation during use and long-term storage, resulting in larger particle size and reduced total surface area, which leads to decreased initiation and detonation performance. This invention provides a RDX explosive crystal and a method for preparing the explosive crystal.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0006] A RDX explosive crystal has a grain size in the micrometer range, and the grain comprises multiple nanostructure units and pores distributed among the multiple nanostructure units.

[0007] The RDX explosive crystals described in this invention have micron-sized particles with nano-structural units and pores distributed among these units. During initiation or propagation reactions, the nano-structural units react with the oxidant through these pores, shortening the combustion reaction diffusion distance to the nanometer level. This results in the large surface area and propagation / initiation performance of nano-explosives. Furthermore, by crystallizing into micron-sized particles, the explosive exhibits higher stability than nano-sized explosives. During use and transportation, the possibility of re-agglomeration and maturation of micron-sized particles is relatively small, thus maintaining the large surface area and propagation / initiation performance of nano-explosives. This combination of the excellent initiation and propagation performance of nano-explosives and the structural stability of micron-sized explosives provides a unique advantage.

[0008] Preferably, in the RDX explosive crystal of the present invention, the size of the nanostructure unit is 50~800nm.

[0009] As a preferred embodiment of the present invention, by further optimizing the size of the nanostructure unit, the detonation velocity and detonation pressure of the explosive are further improved, the energy release rate is inversely proportional to the size of the nanostructure unit, and the energy output is further improved.

[0010] Preferably, the RDX explosive crystals of the present invention have a grain size of 8~30μm.

[0011] As a preferred embodiment of the present invention, by controlling the particle size to be 8~30μm, while possessing the large surface area and detonation initiation performance of nano-explosives, the surface oxidation or decomposition reaction rate of micron-sized particles is lower and the temperature cycling stability is better.

[0012] Preferably, the RDX explosive crystals of the present invention have spherical grains.

[0013] As a preferred embodiment of the present invention, based on the performance advantages of combining the high reactivity of nanocrystals with that of micron-sized spherical particles, the spherical particles have the smallest angle of repose and excellent flowability, enabling high filling density and uniform agent distribution. The spherical particles can achieve the densest packing, improving the volumetric energy density of the filling. Its high energy density and high filling density achieve maximum power in a limited space, making it more suitable for precision detonating elements, 3D printed explosives, or polymer-bonded explosives, improving printing accuracy and mechanical properties.

[0014] To achieve the objectives of this invention, the present invention provides a technical solution:

[0015] An application of RDX explosive, used in at least one of the following: initiating explosive, detonating explosive, and microdevice.

[0016] As a preferred embodiment of the present invention, the RDX explosive of the present invention is used as an initiating explosive, which is easily excited by weak energy, can reduce ignition current / voltage, and improve the system's response capability to weak signals; it can transition from combustion to stable detonation within an extremely short millimeter-level distance, without the need for a long charge; when used as a detonating charge, it has a stronger detonation transmission capability. At the same density, RDX with nanostructure units has a slightly higher detonation velocity and detonation pressure than micron-sized RDX, and can more reliably detonate insensitive main charges; when used in microdevices, it can achieve stable detonation within microchannels, is suitable for high-frequency, high-speed controlled microsystems, greatly reduces the weight and volume of microdevices, is suitable for integration on chips, and can be directly manufactured on microbridges or microchannels through inkjet printing, electrophoretic deposition, and other technologies, with good process compatibility.

[0017] To achieve the objectives of this invention, the present invention provides a technical solution:

[0018] A method for preparing explosive crystals, capable of preparing the RDX explosive crystals described in this invention, includes the following steps:

[0019] S1. Dissolve the explosive raw materials in an organic solvent to obtain an explosive solution;

[0020] S2. Dissolve the additive in the antisolvent to obtain an antisolvent solution;

[0021] S3. Under stirring conditions, the explosive solution is added to the antisolvent solution to precipitate a crystallized product;

[0022] S4. Separate the crystallized product, wash and dry it to obtain explosive crystals.

[0023] The explosive crystal preparation method of the present invention, through the combination of the above steps, the selection of additives and antisolvents, and the control of the crystallization process of explosive raw materials, easily obtains explosives with nano-structural units with large specific surface area and micron-sized grains. The structure and morphology are highly adjustable, thereby obtaining explosives that combine the excellent initiation and detonation performance of nano-explosives with the structural stability of micron-sized explosives. The prepared explosives are not prone to aging and failure. On the basis of ensuring reliable performance, the process is simple and easy to scale up.

[0024] Preferably, the explosive crystal preparation method of the present invention prepares RDX explosive crystals, wherein the explosive raw material is RDX raw material, and organic solvents and additives that are matched with the RDX raw material are used respectively.

[0025] As a preferred embodiment of the present invention, the process for preparing RDX explosive crystals has higher reliability and is easier to control the morphology of the nanostructure units of RDX explosive crystals.

[0026] Preferably, in the method for preparing explosive crystals according to the present invention, the organic solvent includes one or more of the following: cyclohexanone, ethyl acetate, acetone, N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, dimethyl sulfoxide, acetonitrile, tetrahydrofuran, and dioxane.

[0027] As a preferred embodiment of the present invention, an organic solvent containing one or more of the above-mentioned substances is used to further optimize the microstructure of the explosive, such as optimizing the morphology of the nanostructure units, which is more conducive to generating nanostructure units with the target morphology and further improving the specific surface area of ​​the nanostructure units.

[0028] Preferably, in the explosive crystal preparation method of the present invention, the additives include one or more of Tween, Span, sodium dodecyl sulfate, sodium dodecylbenzene sulfonate, sodium stearate, hexadecyltrimethylammonium bromide, dodecyltrimethylammonium chloride, polyethylene glycol, and lecithin.

[0029] As a preferred embodiment of the present invention, by using the above-mentioned additives in conjunction with the preparation of RDX explosive crystals, the compatibility with RDX explosive raw materials is improved, and the morphology of the nanostructure units can be more precisely controlled.

[0030] Preferably, in the method for preparing explosive crystals according to the present invention, the mass fraction of the additive in the antisolvent solution is 0.01% to 20%.

[0031] As a preferred embodiment of the present invention, the morphology and size of the crystallized product are further controlled by controlling the mass fraction of the additive.

[0032] Preferably, in the method for preparing explosive crystals according to the present invention, the temperature of the antisolvent is -20°C to 30°C; and the temperature of the organic solvent is below 60°C.

[0033] As a preferred embodiment of the present invention, the particle size and morphology of the micro-nano structure units of the crystallized product can be further controlled by controlling the temperature of the antisolvent and the temperature of the organic solvent.

[0034] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0035] 1. The RDX explosive crystals described above have micron-sized grains and contain nanostructure units and pores distributed among these units. During initiation or detonation propagation, the nanostructure units react with the oxidant through these pores, shortening the combustion reaction diffusion distance to the nanometer level. This results in the large specific surface area and excellent initiation and detonation propagation performance characteristic of nano-explosives. Furthermore, by crystallizing into micron-sized grains, they exhibit higher stability than traditional nano-explosives. During use and transportation, the possibility of re-agglomeration and maturation of the micron-sized grains is relatively small, thus maintaining the large specific surface area and initiation and detonation propagation performance of nano-explosives, combining the superior initiation and detonation propagation performance of nano-explosives with the structural stability of micron-sized explosives.

[0036] 2. The explosive crystal preparation method described above, through the combination of the above steps, selects additives and antisolvents to control the crystallization process of explosive raw materials, making it easy to obtain explosives with nano-structural units with large specific surface area and micron-sized grains. Moreover, the explosives have extremely high adjustability in structure and morphology, thereby obtaining explosives that combine the excellent initiation and detonation performance of nano-explosives with the structural stability of micron-sized explosives. The prepared explosives are not prone to aging and failure. On the basis of ensuring performance reliability, the process is simple and easy to scale up. Attached Figure Description

[0037] Figure 1 This is a SEM image of a single crystal of the RDX explosive crystal of the present invention;

[0038] Figure 2This is a SEM image of the RDX explosive crystals of the present invention;

[0039] Figure 3 This is a schematic flowchart of the method for preparing explosive crystals according to the present invention;

[0040] Icons: 1. Grain; 11. Nanostructure unit; 12. Pore. Detailed Implementation

[0041] The present invention will now be described in detail with reference to the accompanying drawings.

[0042] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0043] Example 1:

[0044] refer to Figure 1 and Figure 2 This embodiment discloses a RDX explosive crystal, the particle size of which is on the micrometer scale. The particle size of the crystal 1 includes multiple nanostructure units 11 and pores 12 distributed among the multiple nanostructure units 11.

[0045] In this invention, the term "grain 1" is understood as a conventional technical term in energetic materials, materials science, and ceramics. Compared to soft agglomerates formed through traditional agglomeration and ripening, the grain 1 of this invention can be understood as a hard agglomerate. Hard agglomerates exhibit sintering necks, recrystallization, or chemical bonding forces, and the binding forces between microstructural units are stronger than in soft agglomerates. Therefore, compared to soft agglomerates where only van der Waals forces exist, the nanostructural units in the grain 1 of the explosive crystal of this invention are difficult to disperse using simple physical methods, such as stirring or ordinary ultrasound. For example, multiple nanostructural units 11 of the grain 1 of this invention are connected by intermolecular forces, and pores 12 exist or are distributed among the nanostructural units 11. The term "micrometer-scale" in this invention is understood as a particle size of 1 μm or larger. Preferably, in this embodiment, the particle size of the grain 1 is 8–30 μm.

[0046] The nanostructure unit 11 of this invention, referenced Figure 1 As shown, the nanostructure unit 11 forms the framework of the grain 1, making the microstructure of the grain 1 nanoscale; the nanoscale of the present invention is understood as a structural unit of 1-100nm or 100~900nm, specifically, the size of the nanostructure unit 11 is 50~800nm.

[0047] For more specific details, please refer to Figure 2 and Figure 1 As shown. Specifically, the grain 1 of the present invention is spherical.

[0048] refer to Figure 1 As shown, the nanostructure unit 11 of the present invention is understood as a nanocrystal 1 with a microscale size of nanometers.

[0049] Example 2:

[0050] Based on Example 1, this example discloses an application of RDX explosive, used in at least one of the following: initiating explosive, detonating explosive, and microdevice.

[0051] In this embodiment, the microdevice is understood to be a device with an overall size of 1mm to 5mm. For example, it could be a microelectromechanical system (MEMS) device containing energy or a micro pyrotechnic device. The core functional areas of the microdevice, the ignition bridge and the reaction channel, have a size between 10μm and 500μm, making them suitable for loading and using with the RDX explosive of this invention.

[0052] Example 3:

[0053] This embodiment discloses a method for preparing explosive crystals, capable of preparing the RDX explosive crystals of Example 1, referencing... Figure 3 As shown, the steps include:

[0054] S1. Dissolve the explosive raw materials in an organic solvent to obtain an explosive solution;

[0055] S2. Dissolve the additive in the antisolvent to obtain an antisolvent solution;

[0056] S3. Under stirring conditions, the explosive solution is added to the antisolvent solution to precipitate crystallized products;

[0057] S4. Separate the crystalline product, wash and dry it to obtain the explosive.

[0058] In this preferred embodiment, the RDX explosive crystals are prepared using the aforementioned method, with the RDX raw material being RDX raw material, and organic solvents and additives that are compatible with the RDX raw material being used respectively.

[0059] In this embodiment, the organic solvent is understood to be an organic solvent matched with the RDX raw material, which can be selected according to the conventional selection of RDX raw material. Preferably, the organic solvent in this embodiment includes one or more of the following: cyclohexanone, ethyl acetate, acetone, N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, dimethyl sulfoxide, acetonitrile, tetrahydrofuran, and dioxane.

[0060] In this embodiment, the additive is understood to be an additive matched with the RDX raw material, whose function is to control the morphology of the explosive crystals. Specifically, the additive includes one or more of Tween, Span, sodium dodecyl sulfate, sodium dodecylbenzene sulfonate, sodium stearate, hexadecyltrimethylammonium bromide, dodecyltrimethylammonium chloride, polyethylene glycol, and lecithin. More specifically, the mass fraction of the additive in the antisolvent solution is 0.01% to 20%.

[0061] The antisolvent described in this embodiment is used to precipitate the product from the solvent. Specifically, the antisolvent includes one or more of water, ethanol, ethylene glycol, n-propanol, and isopropanol. More specifically, the temperature of the antisolvent is -20℃ to 30℃; the temperature of the organic solvent is below 60℃.

[0062] Example 4:

[0063] Based on Example 3, this example discloses a method for preparing explosive crystals, used to prepare RDX explosive crystals, specifically including the following steps:

[0064] Dissolve an appropriate amount of RDX raw material in cyclohexanone to prepare a saturated solution at 40°C.

[0065] Dissolve an appropriate amount of Tween in ethanol, preferably Tween 80, so that the Tween content is 1% of the ethanol mass. Cool the ethanol to -10°C. Under magnetic stirring, rapidly add 1 ml of RDX solution to 15 ml of ethanol at a rate of 1 ml / s. Continue stirring for 1 minute at a stirring rate of 500 rpm.

[0066] The crystallized mixture was poured into a vacuum filtration flask and then washed with room temperature ethanol.

[0067] The sample was removed and vacuum dried at 80°C for 2 hours to obtain RDX explosive crystals.

[0068] Example 5:

[0069] Based on Example 3, this example discloses a method for preparing explosive crystals, used to prepare RDX explosive crystals, specifically including the following steps:

[0070] Dissolve an appropriate amount of RDX raw material in cyclohexanone to prepare a saturated solution at 60°C. Dissolve an appropriate amount of Tween-80 in ethanol to make the Tween-80 content 1% of the ethanol mass. Cool the ethanol to -10°C.

[0071] Under magnetic stirring, 1 ml of RDX solution was rapidly added to 15 ml of ethanol at a rate of 2 ml / s. Stirring continued for 1 minute at a rate of 500 rpm.

[0072] The crystallized mixture was poured into a vacuum filtration flask and vacuum filtered, then washed with room temperature ethanol. The sample was removed and vacuum dried at 80°C for 2 hours to obtain RDX explosive crystals.

[0073] Example 6:

[0074] Based on Example 3, this example discloses a method for preparing explosive crystals, used to prepare RDX explosive crystals, specifically including the following steps:

[0075] Dissolve an appropriate amount of RDX raw material in N-methylpyrrolidone to prepare a saturated solution at 40°C.

[0076] Dissolve an appropriate amount of Tween-80 in ethanol to make the Tween-80 content 1% of the ethanol mass. Cool the ethanol to -10°C.

[0077] 1 ml of RDX solution was rapidly added to 15 ml of ethanol with magnetic stirring at a rate of 1 ml / s. Stirring continued for 1 minute at a stirring rate of 500 rpm.

[0078] The crystallized mixture was poured into a vacuum filtration flask and vacuum filtered, then washed with room temperature ethanol. The sample was removed and vacuum dried at 80°C for 2 hours to obtain RDX explosive crystals.

[0079] Example 7:

[0080] Based on Example 3, this example discloses a method for preparing explosive crystals, used to prepare RDX explosive crystals, specifically including the following steps:

[0081] Dissolve an appropriate amount of RDX raw material in N-methylpyrrolidone to prepare a saturated solution at 60°C.

[0082] Dissolve an appropriate amount of Tween-80 in ethanol to make the Tween-80 content 1% of the ethanol mass. Cool the ethanol to -10°C.

[0083] Under magnetic stirring, 1 ml of RDX solution was rapidly added to 15 ml of ethanol at a rate of 2 ml / s. Stirring continued for 1 minute at a rate of 500 rpm.

[0084] The crystallized mixture was poured into a vacuum filtration flask and vacuum filtered, then washed with room temperature ethanol. The sample was removed and vacuum dried at 80°C for 2 hours to obtain RDX explosive crystals.

[0085] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A crystal of hexogen explosive, characterized by, The grain (1) has a particle size in the micrometer range. The grain (1) includes multiple nanostructure units (11) and pores (12) distributed among the multiple nanostructure units (11).

2. The RDX crystal of claim 1, wherein, The size of the nanostructure unit (11) is 50~800nm.

3. The RDX crystal of claim 1, wherein, The grain size of the grain (1) is 8~30μm.

4. The RDX crystal of claim 1, wherein, The grain (1) is spherical.

5. A method of producing an explosive crystal, characterized by, The preparation of RDX explosive crystals as described in any one of claims 1-4 comprises the following steps: S1. Dissolve the explosive raw materials in an organic solvent to obtain an explosive solution; S2. Dissolve the additive in the antisolvent to obtain an antisolvent solution; S3. Under stirring conditions, the explosive solution is added to the antisolvent solution to precipitate a crystallized product; S4. Separate the crystallized product, wash and dry it to obtain explosive crystals.

6. The method for preparing explosive crystals according to claim 5, characterized in that, To prepare RDX explosive crystals, the raw material for the explosive is RDX raw material, and organic solvents and additives that are matched with the RDX raw material are used respectively.

7. The method for preparing explosive crystals according to claim 6, characterized in that, The organic solvent includes one or more of the following: cyclohexanone, ethyl acetate, acetone, N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, dimethyl sulfoxide, acetonitrile, tetrahydrofuran, and dioxane.

8. The method for preparing explosive crystals according to claim 6, characterized in that, The additives include one or more of Tween, Span, sodium lauryl sulfate, sodium dodecylbenzene sulfonate, sodium stearate, hexadecyltrimethylammonium bromide, dodecyltrimethylammonium chloride, polyethylene glycol, and lecithin.

9. The method of claim 6, wherein the explosive crystal is prepared by the process of claim 1, and the explosive crystal is selected from the group consisting of RDX, HMX, CL-20, and mixtures thereof. The additive has a mass fraction of 0.01% to 20% in the antisolvent solution.

10. The method for preparing explosive crystals according to claim 6, characterized in that, The temperature of the antisolvent is -20℃ to 30℃; the temperature of the organic solvent is below 60℃.

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