Energetic composite based on pickering emulsion template method, synthesis method and application

Abstract

The application provides an energetic composite based on a Pickering emulsion template method, a synthesis method and application. A nano catalyst having good catalytic activity on a double-base propellant is selected as a Pickering emulsion stabilizer after surface modification. A solution of dimethyl sulfoxide, ethyl acetate, toluene or the like in which an energetic compound hexogen or octogen is dissolved is used as a first liquid phase of the Pickering emulsion, a nano catalyst dispersion liquid is used as a second liquid phase of the Pickering emulsion, the first liquid phase of the Pickering emulsion is mixed with the second liquid phase of the Pickering emulsion, and the Pickering emulsion is prepared under the action of ultrasonic or high-speed shearing. The Pickering emulsion template method is used to construct the energetic composite material, and the nano emulsifier is embedded on the surface of the energetic compound, so that the catalytic combustion performance of the nano emulsifier is improved, and the morphology control of the energetic compound is facilitated.

Description

Technical Field

[0001] This invention belongs to the field of solid propellant technology, and relates to energetic complexes, specifically to an energetic complex based on the Pickering emulsion template method, its synthesis method, and its application. Background Technology

[0002] Solid propellant is the power source of missile engines, and its combustion performance directly affects the delivery range, combat effectiveness, and survivability of missile weapons. Burning rate and pressure index are two important characteristic parameters for measuring the combustion performance of solid propellant. Weapon systems generally require propellants to have combustion characteristics with a wide range of burning rate adjustment and a low pressure index, and combustion catalysts are indispensable functional materials for adjusting the burning rate and pressure index of solid propellants.

[0003] Advances in nanomaterials technology have driven the development of nano-combustion catalysts. Their unique small size and surface effects enable nano-catalysts to exhibit extremely high catalytic activity, and the reduced dosage also helps improve propellant energy levels. However, the enormous surface energy of nano-catalysts makes them prone to agglomeration, forming secondary particles. Furthermore, nano-catalysts are susceptible to migration and loss within the propellant, hindering the realization of their superior performance.

[0004] Pickering emulsions are emulsion systems in which solid particulate stabilizers are dispersed in an oil-water phase. Compared with traditional emulsions, Pickering emulsions have advantages such as strong interfacial stability, reduced foaming, renewability, low toxicity, and low cost. They have been widely used in industries such as cosmetics, food, pharmaceuticals, petroleum, and wastewater treatment, but are currently rarely used in the field of solid propellants. Summary of the Invention

[0005] In view of the defects and deficiencies of the existing technology, the purpose of this invention is to provide an energetic complex based on the Pickering emulsion template method, its synthesis method and application, to solve the technical problems of poor dispersion performance of nanoscale catalysts in solid propellants, weak interaction with energetic compounds, easy loss during the process, and poor combustion performance of solid propellants.

[0006] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0007] An energetic complex based on the Pickering emulsion template method includes an energetic compound and an emulsifier; the energetic compound is selected from one or both of RDX and Octogen; the emulsifier is an unmodified emulsifier or a modified emulsifier; the unmodified emulsifier is selected from one or more of nano-metal oxides, graphene-metal oxide composites, and graphene-metal complexes; the modified emulsifier is selected from one or more of modified nano-metal oxides, modified graphene-metal oxide composites, and modified graphene-metal complexes.

[0008] The present invention also has the following technical features:

[0009] Specifically, the nano-metal oxide is selected from one or more of nano-lead oxide, nano-copper oxide, and nano-nickel oxide; the graphene-metal oxide composite is selected from one or more of graphene-lead oxide composite, graphene-copper oxide composite, and graphene-nickel oxide composite; the graphene metal complex is selected from one or more of graphene-Schiff base lead complex, graphene-Schiff base copper complex, graphene-Schiff base nickel complex, graphene-organic acid lead complex, graphene-organic acid copper complex, and graphene-organic acid nickel complex.

[0010] Specifically, the modified nano-metal oxide is selected from one or more of stearic acid-modified nano-lead oxide, stearic acid-modified nano-copper oxide, stearic acid-modified nano-nickel oxide, silane coupling agent-modified nano-lead oxide, silane coupling agent-modified nano-copper oxide, and silane coupling agent-modified nano-nickel oxide; the modified graphene-metal oxide composite is selected from one or more of stearic acid-modified graphene-lead oxide composite, stearic acid-modified graphene-copper oxide composite, stearic acid-modified graphene-nickel oxide composite, silane coupling agent-modified graphene-lead oxide composite, silane coupling agent-modified graphene-copper oxide composite, and silane coupling agent-modified graphene-nickel oxide composite; the modified The graphene metal complex is selected from one or more of the following: stearic acid-modified graphene-Schiff base lead complex, stearic acid-modified graphene-Schiff base copper complex, stearic acid-modified graphene-Schiff base nickel complex, stearic acid-modified graphene-organic acid lead complex, stearic acid-modified graphene-organic acid copper complex, stearic acid-modified graphene-organic acid nickel complex, silane coupling agent-modified graphene-Schiff base lead complex, silane coupling agent-modified graphene-Schiff base copper complex, silane coupling agent-modified graphene-Schiff base nickel complex, silane coupling agent-modified graphene-organic acid lead complex, silane coupling agent-modified graphene-organic acid copper complex, and silane coupling agent-modified graphene-organic acid nickel complex.

[0011] Specifically, the mass ratio of the emulsifier to the energetic compound is 1:(10-1000).

[0012] Specifically, the energetic complex is composed of a first liquid phase and a second liquid phase of a Pickering emulsion; the first liquid phase of the Pickering emulsion is composed of an energetic compound and a first solvent; the second liquid phase of the Pickering emulsion is composed of an emulsifier and a second solvent; the first solvent is selected from one or more of dimethyl sulfoxide, N,N-dimethylformamide, ethyl acetate and toluene; and the second solvent is cyclohexane.

[0013] Specifically, the volume ratio of the first liquid phase of the Pickering emulsion to the second liquid phase of the Pickering emulsion is (1-5):(1-5).

[0014] Specifically, the particle size of the nano-metal oxide is 10–30 nm.

[0015] The present invention also protects a method for synthesizing an energetic complex based on the Pickering emulsion template method as described above. The method includes: dissolving the energetic compound in a first solvent to obtain a first liquid phase of a Pickering emulsion; ultrasonically dispersing an emulsifier in a second solvent to obtain a second liquid phase of a Pickering emulsion; mixing the first liquid phase of the Pickering emulsion and the second liquid phase of the Pickering emulsion, and stirring at a speed of 15,000 to 20,000 rpm for 2 to 3 minutes to obtain the energetic complex.

[0016] Specifically, the preparation process of the modified emulsifier includes: ultrasonically dispersing an unmodified emulsifier in a solvent to obtain an emulsifier dispersion; dissolving a modifier in a solvent at 40–70°C to obtain a modifier solution, wherein the modifier is stearic acid or a silane coupling agent; mixing the emulsifier dispersion and the modifier solution, reacting at 40–70°C for 1–3 hours, and obtaining the modified emulsifier after centrifugation and washing.

[0017] Specifically, the solvent is ethanol.

[0018] This invention also protects the use of the energetic complex based on the Pickering emulsion template method as described above as an energetic component to partially replace single-element explosives in double-base propellants.

[0019] Specifically, based on dry weight, the amount of the energetic composite based on the Pickering emulsion template method added to the double-base propellant is 5–15.75 wt.%.

[0020] The beneficial technical effects of this invention compared to the prior art are as follows:

[0021] (I) This invention employs the Pickering emulsion template method to construct energetic composite materials. Surface-modified nanocatalysts are used as emulsifiers in the Pickering emulsion. These nano-emulsifiers are stable at the two-phase interface, and the structure of the cured composite can be controlled by adjusting the emulsion properties. This promotes the dispersion of the nano-catalyst, solves the problem of easy loss of nano-catalysts, and achieves efficient contact between the nano-catalyst and the energetic compound. This enhances the interaction between the catalyst and the energetic compound, allowing the nano-catalyst to fully exert its superior performance, thereby improving the combustion performance of solid propellants. This energetic composite material synthesized based on the Pickering emulsion template method can replace some RDX and HMX as a functional composite.

[0022] (II) This invention uses the Pickering emulsion template method to construct energetic composite materials, which improves the combustion performance of solid propellants while reducing the amount of inert catalyst used. In addition, the introduction of graphene-based catalysts helps to reduce the sensitivity of solid propellants, thereby helping to improve the mechanical and safety performance of solid propellants, and has good application potential in the field of solid propellants. Attached Figure Description

[0023] Figure 1 This describes the technical route for synthesizing energetic complexes based on the Pickering emulsion template method.

[0024] Figure 2 The image shows the droplet morphology of the stearic acid-modified nano-copper oxide stabilized Pickering emulsion from Example 1.

[0025] Figure 3 The image shows the droplet morphology of the stearic acid-modified nickel oxide nano-stabilized Pickering emulsion from Example 2.

[0026] Figure 4 The image shows the droplet morphology of the Pickering emulsion stabilized by nano-copper oxide modified with silane coupling agent in Example 3.

[0027] Figure 5 This is a droplet morphology diagram of the Pickering emulsion stabilized by the graphene nickel gallate complex in Example 4.

[0028] Figure 6 The differential scanning calorimetry curve of the cured energetic composite is shown. Detailed Implementation

[0029] The technical route of the present invention is as follows: Figure 1 As shown, the specific technical approach is as follows:

[0030] For efficient catalysts based on dual-base propellant combustion, nano-metal oxides, graphene-metal oxide composites, and graphene-metal complexes can be selected as nano-emulsifiers. Specifically, nano-metal oxides can be selected from lead oxide, copper oxide, and nickel oxide; graphene-metal oxide composites can be selected from lead oxide composites, copper oxide composites, and nickel oxide composites; and graphene-metal complexes can be graphene-Schiff alkali metal (lead, copper, nickel) complexes and graphene-organic acid metal (lead, copper, nickel) complexes.

[0031] Considering the hydrophilic and hydrophobic properties of nanoemulsifiers, the above-mentioned nanoemulsifiers can be further surface modified.

[0032] Considering the solubility of elemental energetic compounds RDX and HMX in organic solvents, dimethyl sulfoxide, N,N-dimethylformamide, ethyl acetate, toluene, etc. can be selected as solvents for the first liquid phase. After dissolving RDX and HMX, the first liquid phase is prepared. A solvent that is incompatible with the solvent of the first liquid phase is selected as the solvent of the second liquid phase, in which the nanocatalyst is ultrasonically dispersed as the second liquid phase.

[0033] The prepared first liquid phase and second liquid phase are mixed, with a volume ratio between 1:5 and 5:1. The mass percentage of the nanoemulsifier and the energetic compound RDX (HMX) is between 0.001 and 0.1%. The mixture is placed in a beaker, and a stable Pickering emulsion is prepared by ultrasonication or high-speed shearing. The nanoemulsifier is dispersed at the interface between the two phases. Further, the RDX / HMX-based energetic composite can be prepared by solvent evaporation, freeze-drying, and spray granulation.

[0034] It should be noted that, unless otherwise specified, all raw materials used in this invention are either known in the art or are materials that have been combined and reported in the inventor's project, for example:

[0035] The graphene-nickel gallate complex is a known complex in the prior art, described in the literature Theory-driven design of graphene-nickel gallate nanocomplex as functional catalyst for composite modified double base propellant (Ming Zhang, Fengqi Zhao, Xiuduo Song, Zhifeng Yuan, Ting An, Yanjing Yang, Ying Wang, Xueli Chen, International Journal of Hydrogen Energy, 87(2024)496-504).

[0036] Following the above technical solutions, specific embodiments of the present invention are given below. It should be noted that the present invention is not limited to the following specific embodiments, and all equivalent modifications made based on the technical solutions of this application fall within the protection scope of the present invention.

[0037] Example 1:

[0038] This embodiment provides a method for synthesizing an energetic complex based on the Pickering emulsion template method. The method includes the following steps: 0.5 g of octogen (HMX) is dissolved in 10 mL of dimethyl sulfoxide (DMSO) to prepare a first liquid phase of the Pickering emulsion, wherein the final concentration of octogen in the first liquid phase of the Pickering emulsion is 0.05 g / mL; 0.05 g of stearic acid-modified nano-copper oxide is ultrasonically dispersed in 10 mL of cyclohexane to prepare a second liquid phase of the Pickering emulsion, wherein the final concentration of stearic acid-modified nano-copper oxide in the second liquid phase of the Pickering emulsion is 5 mg / mL; 10 mL of the first liquid phase of the Pickering emulsion and 10 mL of the second liquid phase of the Pickering emulsion are mixed and stirred at 20,000 rpm for 2 min in an ultra-high speed emulsifier to obtain an emulsion-like energetic complex.

[0039] In this embodiment, the preparation process of stearic acid modified nano-copper oxide includes: ultrasonically dispersing 1g of nano-copper oxide (Aladdin, 20nm) in 30mL of ethanol to obtain a nano-copper oxide ethanol dispersion; dissolving 0.01g of stearic acid in 20mL of ethanol at 55℃ to obtain a stearic acid ethanol solution; mixing the above-prepared nano-copper oxide ethanol dispersion with the stearic acid ethanol solution, and then reacting at 55℃ for 2h. After centrifugation, washing with ethanol, and drying, stearic acid modified nano-copper oxide is obtained.

[0040] In the final emulsion-like energetic composite obtained in this embodiment, the mass ratio of stearic acid-modified nano-copper oxide to octogen is 1:10. Figure 2 The image shows the droplet morphology of the emulsion as captured by an optical microscope. It can be seen that the emulsion has good stability. The silane coupling agent modified copper nanoparticles are uniformly dispersed at the interface between the two phases. The HMX-based composite with silane coupling agent modified copper nanoparticles embedded on the surface can be obtained by further curing methods such as solvent evaporation.

[0041] Example 2:

[0042] This embodiment provides a method for synthesizing an energetic complex based on the Pickering emulsion template method. The method includes the following steps: 0.5 g of octogen (HMX) is dissolved in 10 mL of dimethyl sulfoxide (DMSO) to prepare a first liquid phase of the Pickering emulsion, wherein the final concentration of octogen in the first liquid phase of the Pickering emulsion is 0.05 g / mL; 0.05 g of stearic acid-modified nano-nickel oxide is ultrasonically dispersed in 10 mL of cyclohexane to prepare a second liquid phase of the Pickering emulsion, wherein the final concentration of stearic acid-modified nano-nickel oxide in the second liquid phase of the Pickering emulsion is 5 mg / mL; 10 mL of the first liquid phase of the Pickering emulsion and 10 mL of the second liquid phase of the Pickering emulsion are mixed and stirred at 15000 rpm for 2 min in an ultra-high speed emulsifier to obtain an emulsion-like energetic complex.

[0043] In this embodiment, the preparation process of stearic acid modified nano nickel oxide includes: ultrasonically dispersing 1g of nano nickel oxide (commercially available) in 30mL of ethanol to prepare a nano nickel oxide ethanol dispersion; dissolving 0.01g of stearic acid in 20mL of ethanol at 55°C to prepare a stearic acid ethanol solution; mixing the prepared nano nickel oxide ethanol dispersion with the stearic acid ethanol solution, and then reacting at 55°C for 2h. After centrifugation, washing with ethanol, and drying, stearic acid modified nano nickel oxide is obtained.

[0044] In the final emulsion-like energetic composite obtained in this embodiment, the mass ratio of stearic acid-modified nano-nickel oxide to octogen is 1:10. Figure 3 The image shows the droplet morphology of the emulsion as captured by an optical microscope. It can be seen that the emulsion has good stability and can be further cured by solvent evaporation or other curing methods to obtain the HMX-based composite.

[0045] Example 3:

[0046] This embodiment provides a method for synthesizing an energetic complex based on the Pickering emulsion template method. The method includes the following steps: 0.5 g of RDX is dissolved in 10 mL of N,N-dimethylformamide (DMF) to obtain a first liquid phase of the Pickering emulsion, in which the final concentration of RDX is 0.05 g / mL; 0.05 g of silane coupling agent modified copper nanoparticles is ultrasonically dispersed in 10 mL of cyclohexane to obtain a second liquid phase of the Pickering emulsion, in which the final concentration of silane coupling agent modified copper nanoparticles is 5 mg / mL; 10 mL of the first liquid phase and 10 mL of the second liquid phase of the Pickering emulsion are mixed and stirred at 20,000 rpm for 3 min in an ultra-high speed emulsifier to obtain an emulsion-like energetic complex.

[0047] In this embodiment, the preparation process of silane coupling agent modified nano-copper oxide includes: dissolving silane coupling agent KH-550 (2 mL) in 20 mL of ethanol solution to obtain silane coupling agent ethanol solution; ultrasonically dispersing nano-copper oxide (2 g) in 30 mL of ethanol to obtain copper oxide ethanol dispersion; mixing the silane coupling agent ethanol solution and copper oxide ethanol dispersion prepared above, adjusting the pH value to 3-4, hydrolyzing for 1 hour, and then reacting at 55°C for 2 hours. After centrifugation, washing with ethanol, and drying, silane coupling agent modified nano-copper oxide is obtained.

[0048] In the final emulsion-like energetic composite obtained in this embodiment, the mass ratio of silane coupling agent-modified nano-copper oxide to RDX is 1:10. Figure 4 The image shows the droplet morphology of the emulsion, which can be further obtained by curing methods such as solvent evaporation.

[0049] Example 4:

[0050] This embodiment provides a method for synthesizing an energetic complex based on the Pickering emulsion template method. The method includes the following steps: 0.05 g of octogen (HMX) is dissolved in 10 mL of ethyl acetate to obtain a first liquid phase of the Pickering emulsion, in which the final concentration of octogen is 5 mg / mL; 0.025 g of graphene-nickel gallate complex is ultrasonically dispersed in 10 mL of water to obtain a second liquid phase of the Pickering emulsion, in which the final concentration of graphene-nickel gallate is 2.5 mg / mL; 10 mL of the first liquid phase and 10 mL of the second liquid phase of the Pickering emulsion are mixed and stirred at 20,000 rpm for 2 min in an ultra-high speed emulsifier to obtain an emulsion-like energetic complex.

[0051] In the final emulsion-like energetic composite obtained in this embodiment, the mass ratio of graphene nickel gallate complex to octogen is 1:2. Figure 5 The droplet morphology of the emulsion, captured by an optical microscope, allows for the further acquisition of RDX-based composites through curing methods such as solvent evaporation.

[0052] Example 5:

[0053] This embodiment describes the application of the energetic composite obtained in Example 2 as an energetic component to partially replace single-element explosives in double-base propellants. The application includes: spray drying the emulsion-like energetic composite obtained in Example 2 at a temperature of 180°C to obtain a solid energetic composite.

[0054] In this embodiment, the thermal decomposition properties of the above-mentioned solid-state energetic composite were studied, and the results are as follows: Figure 6 As shown. From Figure 6 As can be seen, after being combined with stearic acid-modified nano-nickel oxide, the decomposition peak temperature of octogen decreased from 282.6℃ to 280.5℃, while the heat of decomposition increased from 309.5 J / g to 1823.3 J / g, indicating that combining with nano-nickel oxide promoted the decomposition of HMX. These results suggest that, as the first step in combustion, promoting the thermal decomposition of octogen helps it decompose more quickly and completely in the propellant, thus improving the propellant's combustion performance.

[0055] In this embodiment, the formulation of the double-base propellant is as follows:

[0056] Table 1. Solid Propellant Formulation Composition

[0057]

Claims

1. A method for synthesizing energetic complexes based on the Pickering emulsion template method, characterized in that, The method includes: dissolving an energetic compound in a first solvent to obtain a first liquid phase of a Pickering emulsion; ultrasonically dispersing an emulsifier in a second solvent to obtain a second liquid phase of a Pickering emulsion; mixing the first liquid phase of the Pickering emulsion and the second liquid phase of the Pickering emulsion, and stirring at a speed of 15,000 to 20,000 rpm for 2 to 3 minutes to obtain an energetic complex. The energetic compound is selected from one or both of RDX and Octogen; The emulsifier is either a non-modified emulsifier or a modified emulsifier; The unmodified emulsifier is selected from one or more of nano-metal oxides, graphene-metal oxide composites, and graphene-metal complexes; The modified emulsifier is selected from one or more of the following: modified nano-metal oxides, modified graphene-metal oxide composites, and modified graphene-metal complexes. The nano-metal oxide is selected from one or more of nano-lead oxide, nano-copper oxide, and nano-nickel oxide; The graphene-metal oxide composite is selected from one or more of graphene-lead oxide composite, graphene-copper oxide composite, and graphene-nickel oxide composite. The graphene metal complex is selected from one or more of graphene-Schiff base lead complex, graphene-Schiff base copper complex, graphene-Schiff base nickel complex, graphene-organic acid lead complex, graphene-organic acid copper complex, and graphene-organic acid nickel complex. The modified nano-metal oxide is selected from one or more of the following: stearic acid modified nano-lead oxide, stearic acid modified nano-copper oxide, stearic acid modified nano-nickel oxide, silane coupling agent modified nano-lead oxide, silane coupling agent modified nano-copper oxide, and silane coupling agent modified nano-nickel oxide. The modified graphene-metal oxide composite is selected from one or more of the following: stearic acid-modified graphene-lead oxide composite, stearic acid-modified graphene-copper oxide composite, stearic acid-modified graphene-nickel oxide composite, silane coupling agent-modified graphene-lead oxide composite, silane coupling agent-modified graphene-copper oxide composite, and silane coupling agent-modified graphene-nickel oxide composite. The modified graphene metal complex is selected from one or more of the following: stearic acid-modified graphene-Schiff base lead complex, stearic acid-modified graphene-Schiff base copper complex, stearic acid-modified graphene-Schiff base nickel complex, stearic acid-modified graphene-organic acid lead complex, stearic acid-modified graphene-organic acid copper complex, stearic acid-modified graphene-organic acid nickel complex, silane coupling agent-modified graphene-Schiff base lead complex, silane coupling agent-modified graphene-Schiff base copper complex, silane coupling agent-modified graphene-Schiff base nickel complex, silane coupling agent-modified graphene-organic acid lead complex, silane coupling agent-modified graphene-organic acid copper complex, and silane coupling agent-modified graphene-organic acid nickel complex. The mass ratio of the emulsifier to the energetic compound is 1:(10-1000); The first solvent is selected from one or more of dimethyl sulfoxide, N,N-dimethylformamide, ethyl acetate, and toluene; The second solvent is cyclohexane; The volume ratio of the first liquid phase of the Pickering emulsion to the second liquid phase of the Pickering emulsion is (1-5):(1-5). The particle size of the nano-metal oxide is 10–30 nm; The preparation process of the modified emulsifier includes: ultrasonically dispersing an unmodified emulsifier in a solvent to obtain an emulsifier dispersion; dissolving a modifier in a solvent at 40–70°C to obtain a modifier solution, wherein the modifier is stearic acid or a silane coupling agent; mixing the emulsifier dispersion and the modifier solution, reacting at 40–70°C for 1–3 hours, and obtaining the modified emulsifier after centrifugation and washing. The solvent is ethanol.

2. The energetic complex synthesized by the Pickering emulsion template method as described in claim 1 is used as an energetic component to partially replace single-element explosives in double-base propellants.

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