Composite Acid Inhibited Core-Shell Structure NTO-Based Mixed Explosive Molding Powder and Preparation Method

Abstract

The present invention discloses a composite acid-inhibiting core-shell structured NTO-based mixed explosive shaping powder and a preparation method thereof. First, one of fluororubbers F2311, F2604, F2462, cellulose acetate butyrate CAB, polyurethane Estane 5702, and polyvinyl butyral (PVB) is used as a binder and dissolved in ethyl acetate to form a binder system, which is ultrasonically dispersed and degassed and mixed uniformly with an anhydrous ethanol dispersion of graphite oxide to prepare an acid-inhibiting binder system. Then, it is dropped into a supersaturated aqueous NTO solution after heating, and after stirring, solvent removal, cooling, and filtration, an acid-inhibiting NTO-based mixed explosive shaping powder is obtained. The shaping powder prepared by the present invention has a smooth and dense surface and a stable crystal form. On the basis of effectively inhibiting the acidity of NTO and the shaping powder, it also ensures sufficient thermal conductivity of the shaping powder, realizing the optimization of the thermal performance of the energetic composite material. The process of the present invention is simple, the experimental conditions are mild, the operation is convenient, and it is easy to realize production.

Description

Technical Field

[0001] The present invention relates to the technical field of energetic materials, and more particularly to a composite acid-inhibited core-shell structure NTO-based mixed explosive molding powder and a preparation method thereof. Background Art

[0002] 3-nitro-1,2,4-triazol-5-one (NTO) is an acidic, insensitive energetic material with an energy level comparable to that of RDX, with theoretical detonation velocity and pressure of 8550 m / s and 34.9 GPa, respectively. NTO has excellent safety performance, comparable to the "wood explosive" TATB, and has lower mechanical, thermal, and shock wave sensitivities. Furthermore, NTO has a simple synthesis process and low preparation cost, making it a very important material for applications in weaponry.

[0003] Since the 1990s, NTO, as a high-energy insensitive explosive, has garnered widespread attention from researchers both domestically and internationally. NTO-based mixed explosives have gradually evolved into three broad categories: press-packed, cast, and melt-cast. Press-packed mixed explosives, with their higher charge density and energy levels, are often used in armor-piercing and fragmentation blasting warheads, making them a widely sought-after type of mixed explosive. Press-packed mixed explosives are prepared by pressing explosive molding powder into a molded powder, then adding certain functional additives to the NTO matrix. This powder is then used in weaponry as a mixed explosive, meeting specific requirements during explosive application or improving the overall performance of explosives during use. The acidity of NTO itself can severely corrode the metal casing of equipment warheads, posing a safety threat to weaponry and equipment. This phenomenon inevitably impacts the safety of NTO-based mixed explosives. Furthermore, excessive coating of NTO with a coating agent can affect the thermal conductivity of the matrix material, reducing the energy level of the NTO-based mixed explosive. Therefore, how to effectively inhibit the acidity of NTO at the modeling powder level and reduce its negative impact on thermal conductivity has always been the focus of relevant technical personnel and production companies. Summary of the invention

[0004] In view of this, the present invention provides a composite acid-inhibited core-shell structure NTO-based mixed explosive molding powder and a preparation method, which can generate an acid-inhibited core-shell structure, effectively reduce the acidity of the NTO-based mixed explosive molding powder, inhibit the corrosion of the NTO-based explosive molding powder on the metal, and optimize the thermal conductivity of the molding powder to a certain extent.

[0005] In order to achieve the above object, the present invention adopts the following technical solution:

[0006] Composite acid-inhibiting core-shell structured NTO-based mixed explosive shaping powder, comprising components in the following weight percentages: 80% to 98% of the inner core, 2% to 20% of the outer shell;

[0007] The outer shell wraps the inner core;

[0008] The inner core is 3-nitro-1,2,4-triazole-5-one (NTO), and the outer shell is composed of a composite acid-inhibiting binder system. The composite acid-inhibiting binder system includes a graphite oxide polymer binder system as a functional filler. The polymer binder includes a binder and a plasticizer; the binder is any one of polyvinyl butyral ester, Estane 5702, cellulose acetate butyrate, and fluororubber; the plasticizer is any one of stearic acid, phthalate, trioctyl trimellitate, and tri-n-hexyl citrate.

[0009] The beneficial effects of the above preferred technical solution are as follows: The NTO-based mixed explosive shaping powder provided by the present invention consists of a double-layer core-shell structure. The shell material coating the NTO particles innovatively applies a composite acid-inhibiting binder system, which mainly plays the role of acid inhibition and optimizing the thermal conductivity. The binder system applied in the present invention also plays the role of reducing the sensitivity and increasing the plasticity of the shaping powder, effectively improving the problem that NTO crystal particles are easily exposed on the surface of the shaping powder during the pressing process.

[0010] Preferably, the functional filler added to the composite acid-inhibiting binder system is graphite oxide.

[0011] The beneficial effects of the above preferred technical solution are as follows: When the ethanol dispersion of graphite oxide used in the present invention is added to the system, on the one hand, since there are many oxygen-containing functional groups (such as hydroxyl -OH, carboxyl -COOH, and ether bond -C-O-C-, etc.) on the basal plane and edge of the graphite oxide molecule, it can have a strong interaction with the active hydrogen on the triazole ring of NTO, effectively improving the acid problem caused by the dissociation and escape of H in NTO. At the same time, it cooperates with the polymer binder to coat the surface of the NTO particles, greatly reducing the water solubility of the NTO particles and inhibiting the escape of acidity; on the other hand, graphite oxide itself has excellent thermal conductivity. When used in combination with the polymer binder, it solves the problem that the thermal conductivity of the NTO-based shaping powder becomes poor due to the coating of the polymer binder. And the amount of the graphite oxide functional filler used in the composite acid-inhibiting NTO-based mixed explosive shaping powder of the present invention is extremely small, and at the same time, the amount of the polymer binder used in the traditional aqueous solution-suspension granulation process is also reduced. This is because the many oxygen-containing groups existing in graphite oxide itself will also interact with the polymer binder. Therefore, on the basis of inhibiting the acidity of NTO and optimizing the thermal conductivity, the addition of the functional filler basically does not affect the energy performance of the explosive.

[0012] Further preferably, the acid-suppressing functional filler is an ethanol dispersion of graphite oxide.

[0013] The beneficial effect of the above preferred solution is that the pH value of NTO coated with a graphite oxide and polymer composite binder system is 6.78, which is much less acidic than the pH value of NTO (3.6).

[0014] Preferably, the polymer binder system includes a binder and a plasticizer; the binder is polyvinyl butyral, Estane5702, cellulose acetate butyrate, fluororubber (F2311, 2603, 2462), etc.; the plasticizer is any one of stearic acid, dibutyl phthalate, trioctyl trimellitate, and tri-n-hexyl citrate.

[0015] The beneficial effect of the above preferred technical solution is that after the selected binder system coats the core material NTO particles, shaped powder particles with a smooth and dense surface and a relatively spherical shape can be obtained.

[0016] The present invention also provides a preparation method of the composite acid-suppressing core-shell structured NTO-based mixed explosive shaped powder as described above, including the following steps:

[0017] (1) Take NTO particles in a beaker, add an appropriate amount of water, stir and then let stand to prepare a saturated NTO solution. Then take a small amount of the supernatant and add it to a small beaker containing a certain amount of NTO particles to obtain a supersaturated NTO aqueous suspension.

[0018] (2) Take an appropriate amount of functional filler powder in a small beaker, add an appropriate amount of absolute ethanol, stir and ultrasonicate to obtain an absolute ethanol dispersion of the functional filler.

[0019] (3) Take an appropriate amount of binder and plasticizer in a small beaker, add an appropriate amount of ethyl acetate, stir and then let stand to obtain an ethyl acetate solution of the binder and plasticizer.

[0020] (4) Add the ethanol dispersion of the functional filler and the ethyl acetate solution of the binder and plasticizer to a conical flask, stir and ultrasonically mix to obtain a composite acid-suppressing binder system.

[0021] (5) Add the prepared supersaturated NTO aqueous suspension to a three-necked flask, stir, then heat up, and dropwise add the composite acid-suppressing binder system solution prepared in step (4).

[0022] (6) Keep the reaction solution for a heat preservation reaction, then heat up to drive away ethyl acetate and ethanol in the system, then cool down, filter, wash and dry the suspension in the system, and finally obtain the composite acid-suppressing core-shell structured NTO-based mixed explosive shaped powder.

[0023] The beneficial effects of the above preferred technical solutions are as follows: The preparation method disclosed in the present invention can obtain a composite acid-inhibiting core-shell structured molding powder with an acidity much lower than that of the NTO-based molding powder, and optimize its thermal conductivity.

[0024] Preferably, in step (1), the mass-volume ratio of NTO to the aqueous solution in the supersaturated NTO solution is (30 - 35) g : (500 - 1500) mL; the mass-volume ratio of 3-nitro-1,2,4-triazole-5-one to the supernatant of the saturated NTO aqueous solution in the supersaturated NTO water suspension is (90 - 99) g : (200 - 350) mL.

[0025] The beneficial effects of the above preferred technical solutions are as follows: The supersaturated NTO water suspension prepared in the present invention ensures that a certain amount of NTO particles are suspended in the aqueous solution, which is beneficial for the effective coating of the composite acid-inhibiting binder system and also ensures the yield of the molding powder.

[0026] Preferably, in step (2), the functional filler is monolayer graphene oxide powder, with a particle diameter of 0.5 - 5 μm and a thickness of 0.8 - 1.2 μm. The mass-volume ratio of graphene oxide to absolute ethanol is (0.1 - 1) g : (10 - 100) mL, the ultrasonic frequency and power are 20 kHz and 800 W, and the ultrasonic time is 5 - 20 min.

[0027] The beneficial effects of the above preferred solutions are as follows: The ethanol dispersion of graphene oxide applied in the present invention can ensure the uniform dispersion of graphene oxide and ensure the uniform mixing with the polymer binder.

[0028] Preferably, in step (3), the mass-volume ratio of the binder, plasticizer to ethyl acetate is 1 g : (0.2 - 1.5) g : (10 - 20) mL, the stirring speed is 100 - 400 r / min; the stirring time is 20 - 60 min; the stirring temperature is 20 - 40 °C; the standing time is 2 h - 12 h.

[0029] The beneficial effects of the above solutions are that the technical parameters defined in the present invention can enable the binder and plasticizer to be fully dissolved in ethyl acetate to form a uniform solution, which can achieve full mixing with the ethanol dispersion of graphene oxide and coat the NTO core particles.

[0030] Preferably, in step (4), the mass-volume ratio of the ethanol dispersion of graphene oxide to the ethyl acetate solution of the binder and plasticizer is (1 - 3) mL : (15 - 25) mL; the stirring speed of the mixed solution is 150 - 450 r / min, the stirring time is 10 - 60 min, the ultrasonic frequency and power are 20 kHz and 800 W, and the ultrasonic time is 5 - 30 min.

[0031] The beneficial effect of the above solution is that the technical parameters defined in the present invention can be used to prepare a uniform composite acid-inhibiting binder system, ensuring that solute molecules (graphite oxide, binder, plasticizer) can be uniformly dispersed and fully mixed in a mixed solution of ethyl acetate and absolute ethanol, and achieving uniform coating of NTO core-shell particles.

[0032] Preferably, in step (5), the mass-volume ratio of NTO particles, the supernatant of the NTO saturated solution, and the composite acid-inhibiting binder system described in step (4) in the supersaturated NTO aqueous suspension is (98 - 99.8) g : (150 - 200) mL : (2 - 20) mL; during the dispersion process of NTO particles, the stirring speed is 250 - 550 r / min, and the stirring time is 15 - 35 min; the temperature is raised to 55 °C; the dropping speed is 3 - 120 mL / min, and the stirring speed during the dropping process is 400 - 550 r / min.

[0033] The beneficial effect of the above preferred solution is that the technical parameters defined in the present invention can ensure that the composite acid-inhibiting binder system can be uniformly coated on the surface of NTO particles, thereby achieving the effect of inhibiting acidity.

[0034] Preferably, the heat preservation time of the heat preservation reaction described in step (6) is 20 - 120 min; then the temperature is raised to 60 °C for solvent expulsion, and the solvent expulsion time is 10 - 45 min. The temperature is lowered to below 25 °C, and absolute ethanol is used for washing during the washing process; the drying process is carried out in a vacuum drying oven at 60 - 120 °C.

[0035] The beneficial effect of the above preferred solution is that: the technical parameters defined in the present invention can completely remove absolute ethanol and ethyl acetate from the system, avoiding being mixed in the prepared composite acid-inhibiting core-shell structure NTO-based mixed explosive shaping powder and affecting the use and storage performance. At the same time, the application of the temperature will not affect the crystal form and safety performance of NTO.

[0036] As can be seen from the above technical solutions, compared with the prior art, the present invention discloses a composite acid-inhibiting core-shell structure NTO-based mixed explosive shaping powder and its preparation method, having the following beneficial effects:

[0037] (1) The composite acid-inhibiting binder system used in the present invention is formed by uniformly mixing an absolute ethanol dispersion of graphite oxide and an ethyl acetate solution of a high polymer. Due to the strong interaction between graphite oxide and NTO molecules and the coating of the particles by the high polymer binder, the escape of H ions in NTO molecules is effectively inhibited, and the acidity of the prepared NTO-based mixed explosive shaping powder is effectively reduced;

[0038] (2) The graphene oxide used in the present invention itself has excellent thermal conductivity. When added to the composite acid-inhibiting binder system as a functional filler, it can effectively optimize the thermal conductivity of the molding powder while reducing acidity.

[0039] (3) In the present invention, due to the strong interaction between the graphene oxide itself and the NTO molecules, it can ensure effective inhibition of the acidity of NTO molecules even when the amount of the added polymer binder is small, ensuring that the energy performance of the NTO itself is not affected as much as possible.

[0040] (4) The preparation process of the present invention is simple, easy to operate, has low experimental costs, and mild experimental conditions, so it is easy to achieve large-scale production. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] 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 required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only the embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained according to the provided drawings without creative efforts.

[0042] Figure 1 is a flowchart of the preparation method of the composite acid-inhibiting core-shell structure NTO-based mixed explosive molding powder prepared by the method disclosed in the present invention;

[0043] Figure 2 is a micrograph of the composite acid-inhibiting core-shell structure NTO-based mixed explosive molding powder prepared in Example 1.

[0044] Figure 3 is a micrograph of the composite acid-inhibiting core-shell structure NTO-based mixed explosive molding powder prepared in Example 2.

[0045] Figure 4 is a micrograph of the composite acid-inhibiting core-shell structure NTO-based mixed explosive molding powder prepared in Example 3. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0046] The following will describe in detail, clearly and completely, the technical solutions in the embodiments of the present invention with reference to the drawings in the embodiments. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts belong to the scope of protection of the present invention.

[0047] A composite acid-inhibiting core-shell structure NTO-based mixed explosive molding powder comprises the following components in weight percentages: 80% - 98% of the inner core and 2% - 10% of the outer shell;

[0048] The core is wrapped by a shell.

[0049] The core is 3-nitro-1,2,4-triazole-5-one (NTO), and the shell is composed of a composite acid-inhibiting binder system. The composite acid-inhibiting binder system includes a graphite oxide polymer binder system as a functional filler. The polymer binder system includes a binder and a plasticizer. The binder is any one of polyvinyl butyral, Estane 5702, cellulose acetate butyrate, and fluororubber. The plasticizer is any one of stearic acid, phthalate, trioctyl trimellitate, and tri-n-hexyl citrate.

[0050] Among them, the functional filler added to the composite acid-inhibiting binder system is graphite oxide.

[0051] The polymer binder system includes a binder and a plasticizer. The binder is any one of polyvinyl butyral, Estane 5702, cellulose acetate butyrate, and fluororubber (such as F2311, 2603, 2462, etc.). The plasticizer is any one of stearic acid, phthalate, trioctyl trimellitate, and tri-n-hexyl citrate.

[0052] The present invention also provides a composite acid-inhibiting core-shell structure NTO-based mixed explosive shaping powder as described above and a preparation method thereof, including the following steps:

[0053] (1) Take NTO particles in a beaker, add an appropriate amount of water, stir and then let stand to prepare a saturated NTO solution. Then take a small amount of the supernatant and add it to a small beaker containing a certain amount of NTO particles to obtain a supersaturated NTO water suspension.

[0054] Among them, the mass-volume ratio of NTO to the aqueous solution in the supersaturated NTO solution is (30 - 35) g : (500 - 1500) mL. The mass-volume ratio of 3-nitro-1,2,4-triazole-5-one to the supernatant of the saturated NTO aqueous solution in the supersaturated NTO water suspension is (90 - 99) g : (200 - 350) mL.

[0055] (2) Take an appropriate amount of functional filler powder in a small beaker, add an appropriate amount of absolute ethanol, stir and ultrasonicate to obtain an absolute ethanol dispersion of the functional filler.

[0056] Among them, the functional filler is monolayer graphite oxide powder, with a particle diameter of 0.5 - 5 μm and a thickness of 0.8 - 1.2 μm. The mass-volume ratio of graphite oxide to absolute ethanol is (0.1 - 1) g : (10 - 100) mL. The ultrasonic frequency and power are 20 kHz and 800 W, and the ultrasonic time is 5 - 20 min.

[0057] (3) Take an appropriate amount of binder and plasticizer in a small beaker, add an appropriate amount of ethyl acetate, stir and then let it stand to obtain an ethyl acetate solution of the binder and plasticizer;

[0058] Among them, the mass-volume ratio of the binder, plasticizer and ethyl acetate is 1 g:(0.2 - 1.5) g:(10 - 20) mL, the stirring speed is 100 - 400 r / min; the stirring time is 2 h - 12 h.

[0059] The beneficial effect of the above solution is that the technical parameters defined in the present invention can fully dissolve the binder and plasticizer in ethyl acetate to form a uniform solution, which can be fully mixed with the anhydrous ethanol dispersion of graphite oxide and coat the NTO core particles.

[0060] (4) Add the ethanol dispersion of graphite oxide and the ethyl acetate solution of the binder and plasticizer to a conical flask, stir and ultrasonically mix to obtain a composite acid-inhibiting binder system;

[0061] Among them, the mass-volume ratio of the ethanol dispersion of graphite oxide to the ethyl acetate solution of the binder and plasticizer is (1 - 3) mL:(15:25) mL; the stirring speed of the mixed solution is 150 - 450 r / min, the stirring time is 10 - 60 min, the ultrasonic frequency and power are 20 kHz and 800 W, and the ultrasonic time is 5 - 30 min;

[0062] (5) Add the prepared NTO supersaturated water suspension to a three-necked flask, stir, then heat up, and dropwise add the solution of the composite acid-inhibiting binder system prepared in step (4);

[0063] Among them, the mass-volume ratio of NTO particles, the supernatant of the NTO saturated solution and the composite acid-inhibiting binder system described in step (4) in the supersaturated NTO water suspension is (98 - 99.8) g:(150 - 200) mL:(2 - 20) mL; the stirring speed during the dispersion of NTO particles is 250 - 550 r / min, the stirring time is 15 - 35 min; the temperature is raised to 55 °C; the dropping speed is 3 - 120 mL / min, and the stirring speed during the dropping process is 400 - 550 r / min.

[0064] (6) Keep the reaction solution for a heat preservation reaction, then heat up to drive away ethyl acetate and ethanol in the system, then cool down, filter, wash and dry the suspension in the system, and finally obtain the composite acid-inhibiting core-shell structure NTO-based mixed explosive shaping powder.

[0065] Among them, the heat preservation time of the heat preservation reaction is 20 to 120 min; then it is heated to 60 °C for solvent expulsion, and the solvent expulsion time is 10 to 45 min. The temperature is lowered to below 25 °C, and anhydrous ethanol is used for washing during the washing process; the drying process is carried out in a vacuum drying oven at 60 to 120 °C.

[0066] Example 1:

[0067] Example 1 of the present invention provides a composite acid-inhibiting core-shell structure NTO-based mixed explosive molding powder, which specifically includes the following steps:

[0068] (1) At room temperature, take 30 g of NTO particles in a beaker, add 500 mL of deionized water, stir and then let it stand to prepare a saturated NTO solution. Then take 200 mL of the supernatant and add it to a small beaker containing 95 g of NTO particles to obtain a supersaturated NTO water suspension;

[0069] (2) Take 0.1 g of graphite oxide powder (particle sheet diameter is 0.5 to 5 μm, thickness is 0.8 to 1.2 μm) in a small beaker, add 20 mL of anhydrous ethanol, and perform ultrasonic treatment at 20 kHz and 800 W for 10 min to obtain an anhydrous ethanol dispersion of the functional filler;

[0070] (3) Take 1 g of cellulose acetate butyrate (CAB) and 0.2 g of stearic acid in a small beaker, add 10 mL of ethyl acetate, stir at a speed of 200 r / min for 20 min, set the stirring temperature to 30 °C, and let it stand for 2 h after stirring to obtain an ethyl acetate solution of the binder and the plasticizer;

[0071] (4) Add 1 mL of the ethanol dispersion of graphite oxide and 15 mL of the ethyl acetate solution of the binder and the plasticizer to a conical flask, stir at a speed of 200 r / min for 20 min, and perform ultrasonic mixing at 20 kHz and 800 W for 10 min to obtain a composite acid-inhibiting binder system;

[0072] (5) Add the prepared supersaturated NTO water suspension to a three-necked flask, stir at a stirring speed of 250 °C for 20 min, then heat up to 55 °C, and dropwise add the composite acid-inhibiting binder system solution prepared in step (4) at a dropping speed of 10 mL / min, wherein the stirring speed during the dropping process is 400 r / min;

[0073] (6) Keep the reaction solution at a constant temperature for 30 min, then raise the temperature to 60 °C to disperse ethyl acetate and ethanol in the system for 20 min. Then cool down to 25 °C, filter the suspension in the system, wash it with absolute ethanol, and then conduct vacuum drying at 60 °C to finally obtain the shaped powder of the composite acid-inhibiting core-shell structure NTO-based mixed explosive.

[0074] Example 2

[0075] Example 2 of the present invention provides a shaped powder of a composite acid-inhibiting core-shell structure NTO-based mixed explosive, which specifically includes the following steps:

[0076] (1) At room temperature, take 30 g of NTO particles in a beaker, add 600 mL of deionized water, stir and then let it stand to prepare a saturated NTO solution. Then take 200 mL of the supernatant and add it to a small beaker containing 96 g of NTO particles to obtain an NTO supersaturated water suspension.

[0077] (2) Take 0.2 g of graphite oxide powder (particle diameter: 0.5 - 5 μm, thickness: 0.8 - 1.2 μm) in a small beaker, add 30 mL of absolute ethanol, and perform ultrasonic treatment at 20 kHz and 800 W for 20 min to obtain an absolute ethanol dispersion of the functional filler.

[0078] (3) Take 1 g of fluororubber F2311 and 0.5 g of dibutyl phthalate in a small beaker, add 20 mL of ethyl acetate, stir at a speed of 300 r / min for 30 min, set the stirring temperature to 40 °C, and let it stand for 4 h after stirring to obtain an ethyl acetate solution of the binder and the plasticizer.

[0079] (4) Add 1.5 mL of the ethanol dispersion of graphite oxide and 20 mL of the ethyl acetate solution of the binder and the plasticizer to a conical flask, stir at a speed of 300 r / min for 30 min, and perform ultrasonic mixing at 20 kHz and 800 W for 20 min to obtain a composite acid-inhibiting binder system.

[0080] (5) Add the prepared NTO supersaturated water suspension to a three-necked flask, stir at a stirring speed of 300 r / min for 25 min, then raise the temperature to 55 °C, and dropwise add the solution of the composite acid-inhibiting binder system prepared in step (4) at a dropping rate of 20 mL / min, with the stirring speed during the dropping process being 500 r / min.

[0081] (6) Keep the reaction solution at a constant temperature for 40 min, then raise the temperature to 60 °C to disperse ethyl acetate and ethanol in the system for 30 min. Then cool down to 25 °C, filter the suspension in the system, wash it with absolute ethanol, and then conduct vacuum drying at 70 °C to finally obtain the shaped powder of the composite acid-inhibiting core-shell structured NTO-based mixed explosive.

[0082] Example 3

[0083] Example 3 of the present invention provides a shaped powder of a composite acid-inhibiting core-shell structured NTO-based mixed explosive, which specifically includes the following steps:

[0084] (1) At room temperature, take 35 g of NTO particles in a beaker, add 700 mL of deionized water, stir and then let it stand to prepare a saturated NTO solution. Then take 250 mL of the supernatant and add it to a small beaker containing 96 g of NTO particles to obtain an NTO supersaturated water suspension.

[0085] (2) Take 0.3 g of graphite oxide powder (particle diameter: 0.5 - 5 μm, thickness: 0.8 - 1.2 μm) in a small beaker, add 40 mL of absolute ethanol, and perform ultrasonic treatment at 20 kHz and 800 W for 15 min to obtain an absolute ethanol dispersion of the functional filler.

[0086] (3) Take 1 g of polyvinyl butyral and 0.6 g of tributyl trimellitate in a small beaker, add 20 mL of ethyl acetate, stir at a speed of 400 r / min for 40 min, set the stirring temperature to 35 °C, and let it stand for 4 h after stirring to obtain an ethyl acetate solution of the binder and the plasticizer.

[0087] (4) Add 3 mL of the ethanol dispersion of graphite oxide and 25 mL of the ethyl acetate solution of the binder and the plasticizer to a conical flask, stir at a speed of 300 r / min for 40 min, and perform ultrasonic mixing at 20 kHz and 800 W for 20 min to obtain a composite acid-inhibiting binder system.

[0088] (5) Add the prepared NTO supersaturated water suspension to a three-necked flask, stir at a stirring speed of 350 r / min for 30 min, then raise the temperature to 55 °C, and dropwise add the solution of the composite acid-inhibiting binder system prepared in step (4) at a dropping rate of 25 mL / min, where the stirring speed during the dropping process is 500 r / min.

[0089] (6) Keep the reaction solution at a constant temperature for 60 min, then raise the temperature to 60 °C to drive off ethyl acetate and ethanol in the system for 30 min. Then cool down to 25 °C, filter the suspension in the system, wash it with absolute ethanol, and then conduct vacuum drying at 85 °C to finally obtain the shaped powder of the composite acid-inhibited core-shell structured NTO-based mixed explosive.

[0090] Comparative Example 1

[0091] The method for preparing the shaped powder of NTO-based mixed explosive (0-NTO) with an ethanol dispersion of graphite oxide without adding functional filler comprises the following steps:

[0092] Take 30 g of NTO particles in a beaker, add 500 mL of deionized water to prepare a saturated NTO solution. Then take 250 mL of the supernatant and add it to a small beaker containing 96 g of NTO particles to obtain a supersaturated aqueous NTO suspension; take 1 g of cellulose acetate butyrate and 0.6 g of tributyl trimellitate in a small beaker, add 20 mL of ethyl acetate, stir and then let it stand for 4 h to obtain an ethyl acetate solution of the binder and plasticizer; add the prepared supersaturated aqueous NTO suspension to a three-necked flask, stir at a stirring speed of 350 r / min for 30 min, then raise the temperature to 55 °C, and add the ethyl acetate solution of the polymer binder dropwise at a dropping rate of 25 mL / min, and adjust the stirring speed to 400 r / min; keep the reaction solution at a constant temperature for 60 min, then raise the temperature to 60 °C, and then cool down to 25 °C, filter and wash the suspension in the system, and then conduct vacuum drying to finally obtain the shaped powder of NTO-based mixed explosive (0-NTO) with an ethanol dispersion of graphite oxide without adding functional filler.

[0093] Effect verification

[0094] Take 5 g of each of the shaped powder particles of the composite acid-inhibited core-shell structured NTO-based mixed explosive obtained in Examples 1, 2, and 3, put them into 100 mL of deionized water, stir for 10 - 20 min, and then measure the pH value of the supernatant liquid. The results are shown in Table 1 below. The pH values of NTO single substance and the comparative NTO-based shaped powder prepared in Comparative Example 1 with an ethanol dispersion of graphite oxide without adding functional filler were measured to be 3.6 and 4.3 respectively by the same method.

[0095] From the above results, it can be known that the composite acid-inhibited binder system prepared with the functional filler selected in the present invention can very effectively solve the problem of the acidity of the shaped powder caused by the escape of H⁺ ions in NTO.

[0096] Table 1 pH values of NTO-based mixed explosive shaped powder

[0097] Sample solution (5 g / 100 mL) pH value (average value obtained three times) Example 1 6.43 Example 2 6.57 Example 3 6.61 NTO 3.6 0-NTO 4.3

[0098] The micro-morphology of the composite acidic inhibitor-based core-shell structured NTO-based mixed explosive shaped powders prepared in Examples 1 to 3 was observed using a scanning electron microscope, and the results are as Figures 2 to 4 shown.

[0099] It can be Figure 2 seen that the surface of the NTO-based shaped powder coated with the composite acidic inhibitor-based binder system in Example 1 is smooth and dense, presenting relatively round particles. And under the observation of the electron microscope, each shaped powder particle is formed by the aggregation of several small units through the intermolecular interaction of several sheet-like binders coating the NTO small units, which indicates that the composite acidic inhibitor-based binder system is well coated on the surface of the NTO particles to form a core-shell structure.

[0100] It can be Figure 3 seen that the NTO-based shaped powder coated with the composite acidic inhibitor-based binder system in Example 2 also presents a smooth and dense surface, presenting relatively round particles. And under the observation of the electron microscope, each shaped powder particle is formed by the aggregation of several sheet-like binders coating the NTO small units through intermolecular interaction. The gap between the small units is smaller than that of the shaped powder sheet-like small units obtained in Example 1, which indicates that the composite acidic inhibitor-based binder system is better coated on the surface of the NTO particles to form a core-shell structure.

[0101] It can be Figure 4 seen that the NTO-based shaped powder coated with the composite acidic inhibitor-based binder system in Example 3 presents a smoother and denser surface than those in Examples 1 and 2, presenting very uniform round particles. And under the observation of the electron microscope, the size of the sheet-like binders coating the NTO small units on the shaped powder particles becomes smaller and they are more closely aggregated together, which indicates that the composite acidic inhibitor-based binder system in Example 3 can better coat on the surface of the NTO particles to form a core-shell structure.

[0102] The above specific description further elaborates on the purpose, technical solution, and beneficial effects of the invention. It should be understood that the above is only a specific embodiment of the present invention and is not used to limit the protection scope of the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. Preparation method of composite acid-inhibited core-shell structure NTO-based mixed explosive shaping powder, characterized in that It comprises components in the following weight percentages: 80% - 98% of the core and 2% - 20% of the shell; The core is wrapped by the shell; The core is 3-nitro-1,2,4-triazol-5-one (NTO), and the shell is composed of a composite acid-inhibiting binder system. The composite acid-inhibiting binder system includes a graphite oxide polymer binder system as a functional filler. The polymer binder includes a binder and a plasticizer. The binder is any one of polyvinyl butyral, Estane 5702, cellulose acetate butyrate, and fluororubber. The plasticizer is any one of stearic acid, phthalate, trioctyl trimellitate, and tri-n-hexyl citrate.

2. The preparation method of the composite acid-inhibiting core-shell structure NTO-based mixed explosive shaping powder according to claim 1, characterized in that It includes the following steps: (1) Take NTO particles in a beaker, add an appropriate amount of water, stir and then let it stand to prepare a saturated NTO solution. Then take a small amount of the supernatant and add it to a small beaker containing NTO particles to obtain a supersaturated NTO water suspension; (2) Take an appropriate amount of functional filler powder in a small beaker, add an appropriate amount of absolute ethanol, stir and ultrasonicate to obtain an absolute ethanol dispersion of the functional filler; (3) Take an appropriate amount of binder and plasticizer in a small beaker, add an appropriate amount of ethyl acetate, stir and then let it stand to obtain an ethyl acetate solution of the binder and plasticizer; (4) Add the ethanol dispersion of the functional filler and the ethyl acetate solution of the binder and plasticizer to a conical flask, stir and ultrasonically mix to obtain a composite acid-inhibiting binder system; (5) Add the prepared supersaturated NTO water suspension to a three-necked flask, stir, then heat up, and dropwise add the solution of the composite acid-inhibiting binder system prepared in step (4); (6) Keep the reaction solution under heat preservation reaction, then heat up to drive away ethyl acetate and ethanol in the system, then cool down, filter, wash and dry the suspension in the system, and finally obtain the composite acid-inhibiting core-shell structured NTO-based mixed explosive molding powder.

3. The preparation method of the composite acid-inhibited core-shell structure NTO-based mixed explosive shaping powder according to claim 2, characterized in that, In the said saturated NTO solution, the mass-volume ratio of NTO to the aqueous solution is 30 - 35 g : 500 - 1500 mL; in the supersaturated NTO water suspension, the mass-volume ratio of 3-nitro-1,2,4-triazol-5-one to the supernatant of the saturated NTO aqueous solution is 90 - 99 g : 200 - 350 mL.

4. The preparation method of the composite acid-inhibiting core-shell structured NTO-based mixed explosive shaping powder according to claim 2, characterized in that, The functional filler is monolayer graphite oxide powder, with a particle sheet diameter of 0.5 - 5 μm and a thickness of 0.8 - 1.2 μm. The mass-volume ratio of graphite oxide to absolute ethanol is 0.1 - 1 g : 10 - 100 mL, the ultrasonic frequency and power are 20 kHz and 800 W, and the ultrasonic time is 5 - 20 min.

5. The preparation method of the composite acid-inhibiting core-shell structure NTO-based mixed explosive shaping powder according to claim 2, characterized in that, The mass-volume ratio of the binder and plasticizer to ethyl acetate is 1 g : 0.2 - 1.5 g : 10 - 20 mL, the stirring speed is 100 - 400 r / min; the stirring time is 20 - 60 min; the stirring temperature is 20 - 40 °C; the standing time is 2 h - 12 h.

6. The preparation method of the composite acid-inhibited core-shell structure NTO-based mixed explosive shaping powder according to claim 2, characterized in that, The mass volume ratio of the ethanol dispersion of the graphite oxide to the ethyl acetate solution of the binder and the plasticizer is 1 to 3 mL: 15: 25 mL; the stirring speed of the mixed solution is 150 to 450 r / min, the stirring time is 10 to 60 min, the ultrasonic frequency and power are 20 kHz and 800 W, and the ultrasonic time is 5 to 30 min.

7. The preparation method of the composite acid-inhibiting core-shell structured NTO-based mixed explosive molding powder according to claim 2, characterized in that, The mass volume ratio of the NTO particles to the supernatant of the NTO saturated solution in the complex acid inhibition type binder system in the supersaturated NTO water suspension is 98 to 99.8 g: 150 to 200 mL: 2 to 20 mL; the stirring speed during the dispersion of the NTO particles is 250 to 550 r / min, and the stirring time is 15 to 35 min; the temperature is raised to 55 °C; the dropping speed is 3 to 120 mL / min, and the stirring speed during the dropping process is 400 to 550 r / min.

8. The preparation method of the composite acid-inhibiting core-shell structure NTO-based mixed explosive shaping powder according to claim 2, wherein, In step (6), the heat preservation time of the heat preservation reaction is 20 to 120 min; then the temperature is raised to 60 °C for solvent expulsion, the solvent expulsion time is 10 to 45 min, the temperature is lowered to below 25 °C, and anhydrous ethanol is used for washing during the washing process; the drying process is carried out in a vacuum drying oven at 60 to 120 °C.

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