Low-smoke waterproof pyrotechnic composition and preparation method thereof
By performing polymer surface treatment on the active metal powder and introducing polyaniline intercalated expanded graphite, the problem of insufficient combustion performance of pyrotechnic powder is solved, and the effect of low water absorption, high energy and low smoke production is achieved.
Patent Information
- Application Number
- CN202510192914.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-02-21
- Publication Date
- 2025-05-23
AI Technical Summary
The combustion performance of existing pyrotechnic powder is insufficient, resulting in poor pyrotechnic effect and too slow combustion speed.
The active metal powder is surface treated with waterproof polymers, and the graphite is expanded by adding polyaniline intercalation layer to reduce the smoke rate, forming a new pyrotechnic agent formula based on polymer fluoride-active metals.
The pyrotechnic agents with low water absorption, high energy and low smoke production have been achieved, which improves the combustion performance and pyrotechnic effect, and significantly reduces the amount of smoke.
Smart Images
Figure CN120025220A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of pyrotechnics, and in particular to a low-smoke and waterproof pyrotechnic agent and a preparation method thereof. Background Art
[0002] In the fireworks industry, trace moisture in pyrotechnics has a significant impact on the safety, quality and performance of pyrotechnics. The pyrotechnic effect of pyrotechnics is closely related to its burning speed. Different pyrotechnic effects have different burning speeds. Usually, those that require a fast burning speed have a lower moisture content, such as propellant, firecracker, and package opening medicine, while those that require a slow burning speed have a relatively high moisture content, such as spray saltpeter and flute medicine. For the same type of pyrotechnics, within a certain range, the burning speed decreases as the moisture content increases. Therefore, reasonably controlling and reducing the moisture content of pyrotechnics can not only obtain the desired pyrotechnic effect, but also improve and enhance the combustion performance of pyrotechnics.
[0003] Active metals such as magnesium powder and aluminum powder play an important role in the field of energetic materials such as propellants, explosives and thermites due to their excellent heat release and low-temperature oxidation capabilities. The energetic components composed of active metals such as magnesium powder and aluminum powder and polymer fluorides have a high reaction rate. However, although magnesium powder and aluminum powder have the advantages of small particles and high activity, the highly activated state of the powder surface is very sensitive to its environment and easily interacts with gas and liquid molecules in the environment, causing the surface of the active powder exposed to the air to oxidize and lose its activity, and even spontaneously combust in the air. Therefore, it is of great significance to perform surface treatment on active metal powders.
[0004] Expanded graphite not only has the characteristics of graphite itself, but also has the property of expansion. Under certain conditions, the intercalated substances between the carbon layers of expanded graphite decompose or gasify and release, and the carbon layers of graphite are opened under pressure. The macroscopic manifestation is the axial expansion and volume increase of the graphite sheets. Its large porosity characteristics make it possible to filter and adsorb smoke particles of different sizes. Summary of the invention
[0005] The purpose of the present invention is to solve the problem of insufficient combustion performance of pyrotechnics in the prior art, and to provide a low-smoke and waterproof pyrotechnic agent and a preparation method thereof. The present invention uses waterproof polymers to perform surface treatment on active metals, and reduces the smoke rate by adding polyaniline intercalated expanded graphite, thereby obtaining a new pyrotechnic agent formula based on polymer fluoride-active metals, achieving low water absorption, high energy, and low smoke production of pyrotechnics, and having good application prospects in the field of fireworks and firecrackers.
[0006] The technical solution adopted by the present invention is as follows: A method for preparing a low-smoke and waterproof pyrotechnic agent comprises the following steps:
[0007] S1. Add 3 to 5 parts of silane coupling agent into ethyl acetate and stir thoroughly for 0.5 to 1 hour to obtain a mixed solution; under the protection of an inert atmosphere, disperse 20 to 30 parts of magnesium powder and 10 to 20 parts of aluminum powder in the mixed solution and soak for 2 to 3 hours, and obtain a coupling agent-modified metal powder by filtering and drying;
[0008] S2, mixing hexamethylenediamine and ethyl isocyanate acrylate, reacting at 0-10°C for 0.5-1h to obtain a capping monomer; mixing 5-10 parts of polyetheramine and 3-5 parts of polysiloxane, heating to 80-100°C and reacting for 0.5-1h to obtain a modified polyetheramine, then mixing the modified polyetheramine with 5-10 parts of isophorone diisocyanate, and then adding 0.5-1 part of a chain extender polyethylene glycol and 0.5-1 part of the capping monomer to react for 0.5-1h to obtain a hydrophobic polymer polyurea slurry;
[0009] S3, fully mixing 40-50 parts of the modified metal powder obtained in S1 and 5-10 parts of the polyurea slurry obtained in S2 in a mixer to obtain a metal powder with a capsule coating structure;
[0010] S4. Fully mix 45-50 parts of the metal powder with the capsule-coated structure obtained in S3, 30-35 parts of polytetrafluoroethylene, 5-10 parts of polyaniline intercalated expanded graphite, 3-5 parts of boron powder, 5-10 parts of RDX cyclotrimethylammonium trinitrify and 10-12 parts of nitrocellulose as a combustion aid in a mixer to obtain pyrotechnic powder, and press and mold it into a low-smoke and waterproof pyrotechnic agent using a press.
[0011] Preferably, the preparation process of the polyaniline intercalated expanded graphite comprises the following steps:
[0012] (1) mixing nitric acid and phosphoric acid at a volume ratio of 1:3-5 at room temperature to obtain a mixed solution;
[0013] (2) Add 10 g of flake graphite to 50 mL of the mixed solution obtained in step (1) and stir evenly, then add 5 to 8 g of potassium permanganate (KMnO) 4 , react at 60-80°C for 0.5-1h, then add 10-15mL of acetic anhydride and continue to react for 0.5-1h, remove the waste liquid by suction and obtain a black powder;
[0014] (3) washing the black powder obtained in step (2) with water until the pH value is greater than 5, and then placing the powder in a muffle furnace at 1000° C. for expansion to obtain expanded graphite;
[0015] (4) preparing a 1 mol / L benzenesulfonic acid solution, adding 10 g of ammonium persulfate to 50 mL of the benzenesulfonic acid solution to obtain a solution A; adding 10 to 30 mL of aniline monomer and 3 to 5 g of expanded graphite to 10 mL of the 1 mol / L benzenesulfonic acid solution to obtain a solution B; adding the solution A dropwise to the solution B under a 0°C ice bath condition and magnetically stirring the mixture for 3 to 5 hours to obtain a mixed solution, and filtering, washing, and drying to obtain polyaniline intercalated expanded graphite.
[0016] Preferably, the silane coupling agent is a mixture of one or more of methyltrichlorosilane, aminosilane, vinylsilane and 3-aminopropyltriethoxysilane.
[0017] Preferably, the polysiloxane is 1,3-bis(3-glycidylpropyl)-1,1,3,3-tetramethyldisiloxane or polydimethylsiloxane.
[0018] More preferably, the molecular weight of the polyetheramine is 2000-5000.
[0019] The present invention also provides a low-smoke and waterproof pyrotechnic agent prepared by the preparation method.
[0020] The beneficial effects of the present invention are:
[0021] (1) The present invention uses polyurea polymer to treat the surface of active metal powder to improve the hygroscopicity and combustion performance of pyrotechnic powder. The hygroscopicity of the obtained pyrotechnic powder is not higher than 0.5%, and the combustion calorific value is not lower than 13500 J·g -1 . The large number of carbamate bonds and urea bonds in the molecular structure of polyurea have high stability and water resistance. The isocyanate groups in its molecular chain can react with water molecules to form stable hydrogen bonds, thereby preventing moisture from penetrating into the interior of the active metal powder, effectively improving the hygroscopic properties of the pyrotechnics. The polymer polyurea is coated on the surface of the active metal powder to form a microcapsule structure. The polymer film formed on its surface can not only effectively protect the activity of the metal powder, but also change the charge properties, functional characteristics and surface chemical reaction characteristics of the metal powder surface, improve the dispersibility of the metal particles, and the low melting point of the polymer enables it to burn rapidly at high temperatures, which can effectively promote the energy release of the pyrotechnics reaction process, thereby increasing the combustion heat of the agent.
[0022] (2) The present invention introduces polyaniline intercalated expanded graphite into the pyrotechnic composition system, which significantly reduces the smoke emission of the pyrotechnic composition. The PM generated by the combustion of the pyrotechnic composition is 10 Concentration PM10 ≤60 μg / m 3 , PM 2.5 Concentration PM2.5 ≤32 μg·m 3, with the characteristics of low smoke emission. Expanded graphite not only has the characteristics of graphite itself, but also has expandable characteristics, which makes it have a larger porosity. During the combustion process, pyrotechnics produce smoke particles of different sizes, the main components of which are fluoride particles, metal oxide particles, etc. The nitrogen atoms in polyaniline can form coordination bonds with metal ions on the surface of metal oxides under high temperature conditions, and can be adsorbed on the surface of smoke particles through physical effects such as van der Waals forces and hydrogen bonds, increasing the interface bonding strength between it and expanded graphite, thereby reducing the smoke content generated by the combustion of pyrotechnics.
[0023] (3) The present invention is based on a polymer fluoride-active metal agent system, and introduces an energetic agent RDX cyclotrimethylammonium trinitrile and a combustion aid nitrocellulose, which is beneficial to improving the ignition performance and combustion performance of the pyrotechnic agent. The polymer fluoride-active metal agent system has the characteristics of insensitivity and high energy, but its detonation conditions are high and the ignition performance is poor. The introduction of nitrocellulose and RDX improves the ignition performance of the polymer fluoride-active metal agent system, while making the agent system have the characteristics of excellent detonation performance of the energetic material RDX, and the explosive heat value of the agent system is increased by 15%. BRIEF DESCRIPTION OF THE DRAWINGS
[0024] Figure 1 This is a scanning electron microscope image of the expanded graphite obtained in Example 1. DETAILED DESCRIPTION
[0025] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.
[0026] Example 1
[0027] (1) Add 10 g of flake graphite and 5 g of KMnO to 50 mL of a solution of nitric acid and phosphoric acid in a volume ratio of 1:3. 4 , react at 60°C for 0.5h, add 10mL of acetic anhydride and continue to react for 0.5h, and after filtration and washing, place in a 1000°C muffle furnace to obtain expanded graphite.
[0028] (2) Prepare 1 mol / L benzenesulfonic acid solution, add 10 g of ammonium persulfate to 50 mL of benzenesulfonic acid solution to obtain solution A; add 10 mL of aniline monomer and 3 g of expanded graphite to 10 mL of 1 mol / L benzenesulfonic acid solution to obtain solution B; add solution A dropwise to solution B under 0°C ice bath condition and stir magnetically for 3 h to obtain a mixed solution, and obtain polyaniline intercalated expanded graphite after filtration, washing and drying; the scanning electron microscope image of expanded graphite is shown in the attached figure. Figure 1 shown.
[0029] (3) Under the protection of an inert atmosphere, 3 parts of 3-aminopropyltriethoxysilane were added to ethyl acetate and stirred for 0.5 h. 20 parts of magnesium powder and 10 parts of aluminum powder were added and dispersed in the solution and soaked for 2 h. The modified metal powder was filtered and dried to obtain the modified metal powder.
[0030] (4) Hexamethylenediamine is reacted with ethyl isocyanate acrylate to obtain a capping monomer, 5 parts of a polyetheramine with an average molecular weight of 5000 and 3 parts of polydimethylsiloxane are mixed and reacted at 80° C. for 0.5 h to obtain a modified polyetheramine, which is then mixed with 5 parts of isophorone diisocyanate, and 0.5 parts of polyethylene glycol and 0.5 parts of the capping monomer are added to obtain a polyurea slurry.
[0031] (5) 40 parts of modified metal powder and 5 parts of polyurea slurry are fully mixed in a mixer, and 30 parts of polytetrafluoroethylene, 5 parts of polyaniline intercalated expanded graphite, 3 parts of boron powder, 5 parts of RDX, and 10 parts of nitrocellulose as a combustion aid are added and continued to mix, and the final product is obtained by pressing and molding with a press.
[0032] Example 2
[0033] (1) Add 10 g of flake graphite and 8 g of KMnO to 50 mL of a solution of nitric acid and phosphoric acid in a volume ratio of 1:5. 4 , react at 80°C for 1h, add 15mL of acetic anhydride and continue to react for 1h, and after filtration and washing, place in a 1000°C muffle furnace to obtain expanded graphite.
[0034] (2) preparing a 1 mol / L benzenesulfonic acid solution, adding 10 g of ammonium persulfate to 50 mL of the benzenesulfonic acid solution to obtain a solution A; adding 30 mL of aniline monomer and 5 g of expanded graphite to 10 mL of the 1 mol / L benzenesulfonic acid solution to obtain a solution B; adding the solution A dropwise to the solution B under a 0°C ice bath condition and magnetically stirring for 5 h to obtain a mixed solution, and filtering, washing, and drying to obtain polyaniline intercalated expanded graphite.
[0035] (3) Under the protection of an inert atmosphere, 5 parts of 3-aminopropyltriethoxysilane were added to ethyl acetate and stirred for 1 hour. 30 parts of magnesium powder and 20 parts of aluminum powder were added and dispersed in the solution and soaked for 3 hours. The modified metal powder was filtered and dried to obtain the modified metal powder.
[0036] (4) Hexamethylenediamine is reacted with ethyl isocyanate acrylate to obtain a capping monomer, 10 parts of a polyetheramine with an average molecular weight of 2000 and 5 parts of polydimethylsiloxane are mixed and reacted at 100° C. for 1 hour to obtain a modified polyetheramine, which is then mixed with 10 parts of isophorone diisocyanate, and 1 part of polyethylene glycol and 1 part of the capping monomer are added to obtain a polyurea slurry.
[0037] (5) 50 parts of modified metal powder and 10 parts of polyurea slurry are fully mixed in a mixer, and 35 parts of polytetrafluoroethylene, 10 parts of polyaniline intercalated expanded graphite, 5 parts of boron powder, 10 parts of RDX, and 12 parts of nitrocellulose as a combustion aid are added and continued to mix, and the final product is obtained by pressing and molding with a press.
[0038] Example 3
[0039] (1) Add 10 g of flake graphite and 6 g of KMnO to 50 mL of a solution of nitric acid and phosphoric acid in a volume ratio of 1:4. 4 , react at 70°C for 1h, add 13mL of acetic anhydride and continue to react for 0.8h, and after filtration and washing, place in a 1000°C muffle furnace to obtain expanded graphite.
[0040] (2) preparing a 1 mol / L benzenesulfonic acid solution, adding 10 g of ammonium persulfate to 50 mL of the benzenesulfonic acid solution to obtain a solution A; adding 20 mL of aniline monomer and 4 g of expanded graphite to 10 mL of the 1 mol / L benzenesulfonic acid solution to obtain a solution B; adding the solution A dropwise to the solution B under a 0°C ice bath condition and magnetically stirring for 4 h to obtain a mixed solution, and filtering, washing, and drying to obtain polyaniline intercalated expanded graphite.
[0041] (3) Under the protection of an inert atmosphere, 4 parts of 3-aminopropyltriethoxysilane were added to ethyl acetate and stirred for 1 hour. 25 parts of magnesium powder and 15 parts of aluminum powder were added and dispersed in the solution and soaked for 3 hours. The modified metal powder was filtered and dried to obtain the modified metal powder.
[0042] (4) Hexamethylenediamine is reacted with ethyl isocyanate acrylate to obtain a capping monomer, 8 parts of a polyetheramine with an average molecular weight of 3000 and 4 parts of polydimethylsiloxane are mixed and reacted at 90° C. for 1 hour to obtain a modified polyetheramine, which is then mixed with 8 parts of isophorone diisocyanate, and 0.8 parts of polyethylene glycol and 0.7 parts of the capping monomer are added to obtain a polyurea slurry.
[0043] (5) 45 parts of modified metal powder and 8 parts of polyurea slurry are fully mixed in a mixer, and 33 parts of polytetrafluoroethylene, 7 parts of polyaniline intercalated expanded graphite, 4 parts of boron powder, 8 parts of RDX, and 10 parts of nitrocellulose as a combustion aid are added and continued to mix, and the final product is obtained by pressing and molding with a press.
[0044] Comparative Example 1
[0045] (1) Under the protection of an inert atmosphere, 25 parts of magnesium powder, 15 parts of aluminum powder, 33 parts of polytetrafluoroethylene, 4 parts of boron powder, and 10 parts of nitrocellulose as a combustion aid are uniformly mixed and pressed by a press to obtain a basic formula pyrotechnic agent.
[0046] The pyrotechnic compositions prepared in Examples 1-3 and Comparative Example 1 were tested and compared, including measuring the PM2.5 concentration in ambient air after the new fireworks and firecrackers propellant was completely reacted according to HJ 656-2013 "Technical Specifications for Manual Monitoring Methods for PM2.5 in Ambient Air (Weight Method)"; using an adiabatic oxygen bomb calorimeter to measure the explosion heat and combustion heat of the obtained pyrotechnic compositions; and measuring the moisture absorption rate of the new fireworks and firecrackers propellant according to the hygroscopic dryer equilibrium method in Method 404.1 of GJB 770B-2005 "Test Methods for Propellants". The test results are shown in Table 1.
[0047] Table 1 Smoke density parameters, combustion performance and moisture absorption rate produced by pyrotechnic powder of Examples and Comparative Examples
[0048]
[0049] As shown in Table 1, PM of Examples 1 to 3 10 、PM 2.5 The concentration and moisture absorption rate are lower than those in comparative example 1; the combustion heat and explosion heat are higher than those in comparative example 1, indicating that the pyrotechnic composition obtained by the present invention has the characteristics of low smoke generation, low moisture absorption and high combustion performance.
[0050] The specification and drawings of the present invention are considered to be illustrative rather than restrictive. On the basis of the present invention, those skilled in the art can make some substitutions and modifications to some of the technical features according to the disclosed technical content without creative labor, all of which are within the protection scope of the present invention.
Claims
1. A method for preparing a low-smoke and waterproof pyrotechnic agent, characterized in that: The following steps are involved: S1. Add 3 to 5 parts of silane coupling agent into ethyl acetate and stir thoroughly for 0.5 to 1 hour to obtain a mixed solution; Under the protection of an inert atmosphere, 20 to 30 parts of magnesium powder and 10 to 20 parts of aluminum powder are dispersed in the mixed solution and soaked for 2 to 3 hours, and then filtered and dried to obtain a coupling agent-modified metal powder; S2, mixing hexamethylenediamine and ethyl isocyanate acrylate, reacting at 0-10°C for 0.5-1h to obtain a capping monomer; mixing 5-10 parts of polyetheramine and 3-5 parts of polysiloxane, heating to 80-100°C and reacting for 0.5-1h to obtain a modified polyetheramine, then mixing the modified polyetheramine with 5-10 parts of isophorone diisocyanate, and then adding 0.5-1 part of a chain extender polyethylene glycol and 0.5-1 part of the capping monomer to react for 0.5-1h to obtain a hydrophobic polymer polyurea slurry; S3, fully mixing 40-50 parts of the modified metal powder obtained in S1 and 5-10 parts of the polyurea slurry obtained in S2 in a mixer to obtain a metal powder with a capsule coating structure; S4. Fully mix 45-50 parts of the metal powder with the capsule-coated structure obtained in S3, 30-35 parts of polytetrafluoroethylene, 5-10 parts of polyaniline intercalated expanded graphite, 3-5 parts of boron powder, 5-10 parts of RDX cyclotrimethylammonium trinitrify and 10-12 parts of nitrocellulose as a combustion aid in a mixer to obtain pyrotechnic powder, and press and mold it into a low-smoke and waterproof pyrotechnic agent using a press.
2. The preparation method according to claim 1, characterized in that: The preparation process of the polyaniline intercalated expanded graphite comprises the following steps: (1) mixing nitric acid and phosphoric acid at a volume ratio of 1:3-5 at room temperature to obtain a mixed solution; (2) Add 10 g of flake graphite to 50 mL of the mixed solution obtained in step (1) and stir evenly, add 5 to 8 g of potassium permanganate KMnO4, react at 60 to 80° C. for 0.5 to 1 h, then add 10 to 15 mL of acetic anhydride and continue to react for 0.5 to 1 h, and remove the waste liquid by suction to obtain a black powder; (3) washing the black powder obtained in step (2) with water until the pH value is greater than 5, and then placing the powder in a muffle furnace at 1000° C. for expansion to obtain expanded graphite; (4) preparing a 1 mol / L benzenesulfonic acid solution, adding 10 g of ammonium persulfate to 50 mL of the benzenesulfonic acid solution to obtain a solution A; adding 10 to 30 mL of aniline monomer and 3 to 5 g of expanded graphite to 10 mL of the 1 mol / L benzenesulfonic acid solution to obtain a solution B; adding the solution A dropwise to the solution B under a 0°C ice bath condition and magnetically stirring the mixture for 3 to 5 hours to obtain a mixed solution, and filtering, washing, and drying to obtain polyaniline intercalated expanded graphite.
3. The preparation method according to claim 1, characterized in that: The silane coupling agent is a mixture of one or more of methyltrichlorosilane, aminosilane, vinylsilane and 3-aminopropyltriethoxysilane.
4. The preparation method according to claim 1, characterized in that: The polysiloxane is 1,3-bis(3-glycidylpropyl)-1,1,3,3-tetramethyldisiloxane or polydimethylsiloxane.
5. The preparation method according to claim 1, characterized in that: The molecular weight of the polyetheramine is 2000-5000.
6. The preparation method according to any one of claims 1 to 5 can produce a low-smoke and waterproof pyrotechnic composition.
7. The low smoke and waterproof pyrotechnic composition according to claim 6, characterized in that: The low-smoke and waterproof pyrotechnic agent has a moisture absorption rate of ≤0.5% and a combustion calorific value of ≥13500 J·g -1 The PM generated by the combustion of the low-smoke waterproof pyrotechnic agent 10 Concentration PM10 ≤60 μg / m 3 , PM 2.5 Concentration PM2.5 ≤32 μg·m 3 .