Lead salt modified 5-amino tetrazole-based gas generating agent with low combustion temperature and high combustion rate and preparation method of lead salt modified 5-amino tetrazole-based gas generating agent

Abstract

The invention provides a lead salt modified 5-aminotetrazolyl gas generating agent with low combustion temperature and high combustion rate and a preparation method thereof, the gas generating agent comprises 5-aminotetrazole, strontium nitrate and lead salt, and the mass ratio of the lead salt is 5-10%. According to the invention, the 5-aminotetrazolyl gas generating agent is modified, so that the temperature of the gas generating agent can be reduced, the burning speed can be improved, and the applicability of the gas generating agent as a solid propelling type fire extinguishing device is enhanced.

Description

Technical Field

[0001] This invention belongs to the field of energy material modification technology, and in particular relates to a lead salt modified 5-aminotetrazolium gas-generating agent with low combustion temperature and high combustion rate and its preparation method. Background Technology

[0002] 5-Aminotetrazolium (5AT) / Strontium nitrate (Sr(NO3)2), as a novel energetic material, is often used as a solid propellant gasgenerator formulation in solid propellant gas generators due to its excellent physicochemical properties. However, the 5AT / Sr(NO3)2 formulation suffers from high combustion temperature and low combustion rate, hindering its further application in solid propellant gas generators. Traditional methods involve adding cooling agents such as aluminum hydroxide and calcium carbonate to lower the combustion temperature of the gasgenerator, and adding metal oxides such as copper oxide and lead oxide to increase the combustion rate and promote combustion. However, lowering the combustion temperature is accompanied by a decrease in combustion rate, and increasing the combustion rate while maintaining a high combustion temperature means that traditional additives cannot simultaneously achieve both low combustion temperature and high combustion rate. Lead salts are a common propellant additive. Adding lead-based compounds such as lead carbonate, basic lead carbonate, lead salicylate, and benzoic acid to propellants has been found to decrease the combustion pressure index and increase the combustion rate with pressure. Most lead-based compounds decompose upon combustion at high temperatures to produce lead oxide, which then complexes with other products, thus affecting the combustion rate. For example, lead oxide and M... X (OH) Y (CO3) Z The combination of novel additives yields a new formulation that can both regulate the combustion rate and reduce the propellant temperature, effectively solving the problems of high combustion temperature and low combustion rate inherent in traditional formulations. Summary of the Invention

[0003] In view of this, the present invention aims to overcome the defects in the prior art and proposes a lead salt modified 5-aminotetrazolium gas-generating agent with low combustion temperature and high combustion rate and its preparation method.

[0004] To achieve the above objectives, the technical solution of the present invention is implemented as follows:

[0005] In a first aspect, the present invention provides a lead salt modified 5-aminotetrazolium-based gas-generating agent with low combustion temperature and high combustion rate, comprising 5-aminotetrazolium, strontium nitrate, and lead salt, wherein the mass percentage of lead salt is 5% to 10%.

[0006] Preferably, the lead salt is basic lead carbonate and / or lead carbonate. Since basic lead carbonate and lead carbonate can decompose and absorb heat, and the resulting lead oxide can regulate the combustion rate during combustion, thus increasing the combustion rate, the lead salt of this invention is selected from either basic lead carbonate or lead carbonate.

[0007] Preferably, the 5-aminotetrazole and strontium nitrate are mixed in a zero oxygen balance ratio, that is, the ratio of 5-aminotetrazole to strontium nitrate is 36.52:63.48.

[0008] Secondly, the present invention provides a method for preparing the above-mentioned low-burning-temperature, high-burning-rate lead salt-modified 5-aminotetrazolium-based gas-generating agent, comprising the following steps:

[0009] S1: Mix 5-aminotetrazolium, strontium nitrate, lead salt, and solvent evenly using a wet ball milling method;

[0010] S2: After ball milling, place the ball in an oven to allow the solvent to evaporate completely.

[0011] S3: Use a standard sieve to sieve the dried sample to obtain gas-generating agent powder;

[0012] S4: The gas-generating agent powder is pressed into a column shape using a press machine to obtain the lead salt modified 5-aminotetrazolium gas-generating agent product with low combustion temperature and high combustion rate.

[0013] Preferably, the solvent in step S1 is one or more of anhydrous ethanol, acetone, dichloromethane, and water.

[0014] More preferably, anhydrous ethanol is used as the solvent in step S1.

[0015] Preferably, the volume ratio of the solvent to the total volume of 5-aminotetrazole, strontium nitrate, and lead salt is (2-4):1.

[0016] Preferably, in step S1, the rotation speed of the ball mill is 200-400 r / min, and the ball milling time is 2-4 h.

[0017] Preferably, in step S2, the oven temperature is 50–100°C and the time is 4–10 hours.

[0018] Preferably, the standard sieve in step S3 is an 80-120 mesh sieve, which yields powder with a particle size of less than 180 μm.

[0019] Preferably, step S4 uses a mold with a diameter of 10-25 mm for pressing, applies a pressure of 1-2 MPa, and holds the pressure for 1-3 minutes.

[0020] Compared with the prior art, the present invention has the following advantages:

[0021] (1) The present invention modifies the 5-aminotetrazolium gas-generating agent, which can reduce the temperature of the gas-generating agent while increasing the burning rate, thereby enhancing its applicability as a gas-generating agent in solid propellant fire extinguishing devices.

[0022] (2) The lead salt modified 5-aminotetrazolium gas generator prepared by the present invention is uniform and stable with low combustion temperature and high combustion rate, and its own chemical properties are not changed. The method is simple and easy to operate, and the extremely high yield is conducive to industrial production.

[0023] (3) The low-burning-temperature, high-burning-rate lead salt-modified 5-aminotetrazolium gas generator prepared by the present invention has a short combustion flame and more stable combustion. In a propulsion fire extinguishing device, it can avoid the rapid ejection of flames and increase the safety of the device.

[0024] (4) The preparation method of the lead salt modified 5-aminotetrazolium gas generator of the present invention with low combustion temperature and high combustion rate involves ball milling the gas generator and then sieving it to make the raw materials of the gas generator evenly mixed and press it into a more compacted column, which is conducive to heat transfer during combustion and makes the combustion more complete. Attached Figure Description

[0025] Figure 1 SEM images (b) of the comparative example (a) and the sample prepared by the example after wet ball milling;

[0026] Figure 2 Flame combustion images (b) of samples prepared in Example (a) and Comparative Example;

[0027] Figure 3 Images showing the burning rate as a function of pressure for samples prepared in the examples and comparative examples;

[0028] Figure 4 The images show a physical photograph (a) and a SEM image (b) of the comparative combustion residue, and a physical photograph (c) and a SEM image (d) of the combustion residue of the embodiment. Detailed Implementation

[0029] The embodiments of the present invention are described in detail below. The embodiments described below are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0030] In this document, unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0031] In this document, when values ​​are described as ranges, it should be understood that such disclosure includes disclosure of all possible subranges within that range, as well as the specific numerical values ​​falling within that range, regardless of whether the specific numerical value or specific subrange is explicitly specified.

[0032] In this article, the terms "multiple" or "more than" are used unless otherwise specified, referring to a quantity greater than or equal to 2. For example, "one or more" means one or more types.

[0033] In this document, the terms "preferred" and "more preferred" are used only to describe implementation methods or embodiments with better effects, and should be understood as not constituting a limitation on the scope of protection of this invention.

[0034] In this document, terms such as "further" are used for descriptive purposes to indicate differences in content, but should not be construed as limiting the scope of protection of this invention.

[0035] In this article, the term "and / or" describes an association between objects, indicating that three relationships can exist. For example, A and / or B means: A or B, or A and B.

[0036] In this document, the term "about" means a specified value of + / - 10%, preferably + / - 5%, and more preferably + / - 1%.

[0037] In this article, the terms “include,” “including,” “have,” “contain,” etc., are all open-ended terms, meaning that they include but are not limited to.

[0038] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar to or equivalent to those described herein may be used in the implementation or testing of this invention.

[0039] The present invention will be described in detail below with reference to the embodiments.

[0040] Example 1

[0041] A method for preparing a lead salt-modified gas-generating agent with low combustion temperature and high combustion rate, the specific steps of which are as follows:

[0042] (1) First, prepare 5AT / Sr(NO3)2 according to zero oxygen balance, that is, the ratio of 5AT to Sr(NO3)2 is 36.52:63.48, and add 2PbCO3·Pb(OH)2, which accounts for 10% of the total mass of the gas-generating agent.

[0043] (2) Place the raw material powder into a ball mill jar and add anhydrous ethanol. The volume ratio of anhydrous ethanol to the powder obtained in step (1) is 3:1.

[0044] (3) Place the grinding jar into a planetary centrifugal ball mill, set the rotation speed to 250 r / min, and the time to 4 h.

[0045] (4) After ball milling, place it in an oven, set the temperature to 50℃, and set the timer for 8 hours.

[0046] (5) Remove the gas-generating agent from the oven and sieve it through an 80-mesh standard sieve to obtain a gas-generating agent powder with a particle size of less than 180μm and basically uniform.

[0047] (6) The powder is placed in the press, a pressure of 1.5 MPa is applied, and the pressure holding time is 2 min. A mold with a diameter of 20 mm is used to finally obtain the lead salt modified 5-aminotetrazolium gas generator product with low combustion temperature and high combustion rate.

[0048] In this embodiment, basic lead carbonate was selected as the additive. Basic lead carbonate, strontium nitrate, and 5-aminotetrazolium were uniformly mixed using the method described in this invention. Thermocouples and a high-speed camera were used to study the combustion temperature and flame morphology of the gas-generating agent. The combustion rate of the gas-generating agent was calculated based on the differential method of a closed-circuit reactor.

[0049] Example 2

[0050] A method for preparing a lead salt-modified gas-generating agent with low combustion temperature and high combustion rate, the specific steps of which are as follows:

[0051] (1) First, prepare 5AT / Sr(NO3)2 according to zero oxygen balance, that is, the ratio of 5AT to Sr(NO3)2 is 36.52:63.48, and add PbCO3 accounting for 5% of the total mass of the gas-generating agent.

[0052] (2) Place the raw material powder into a ball mill jar and add anhydrous ethanol. The volume ratio of anhydrous ethanol to the powder obtained in step (1) is 2:1.

[0053] (3) Place the ball mill jar into a planetary centrifugal ball mill, set the rotation speed to 200 r / min, and the time to 4 h.

[0054] (4) After ball milling, place it in an oven, set the temperature to 100℃, and set the timer for 4 hours.

[0055] (5) Remove the gas-generating agent from the oven and sieve it through a 100-mesh standard sieve to obtain a gas-generating agent powder with a particle size of less than 180μm and basically uniform.

[0056] (6) The powder is placed in the press, a pressure of 1 MPa is applied, and the pressure holding time is 3 min. A mold with a diameter of 25 mm is used to finally obtain the lead salt modified 5-aminotetrazolium gas generator with low combustion temperature and high combustion rate.

[0057] Example 3

[0058] A method for preparing a lead salt-modified gas-generating agent with low combustion temperature and high combustion rate, the specific steps of which are as follows:

[0059] (1) First, prepare 5AT / Sr(NO3)2 according to zero oxygen balance, that is, the ratio of 5AT to Sr(NO3)2 is 36.52:63.48. Add a mixture of PbCO3 + 2PbCO3·Pb(OH)2 accounting for 8% of the total mass of the gas-generating agent, wherein the mass ratio of PbCO3 to 2PbCO3·Pb(OH)2 is 1:1.

[0060] (2) Place the raw material powder into a ball mill jar and add anhydrous ethanol. The volume ratio of anhydrous ethanol to the powder obtained in step (1) is 4:1.

[0061] (3) Place the ball mill jar into a planetary centrifugal ball mill, set the rotation speed to 400 r / min, and the time to 4 h.

[0062] (4) After ball milling, place it in an oven, set the temperature to 80℃, and set the timer for 10 hours.

[0063] (5) Remove the gas-generating agent from the oven and sieve it through a 120-mesh standard sieve to obtain a gas-generating agent powder with a particle size of less than 180μm and basically uniform.

[0064] (6) The powder is placed in the press, a pressure of 2MPa is applied, and the pressure holding time is 1min. A mold with a diameter of 10mm is used to finally obtain the lead salt modified 5-aminotetrazolium gas generator product with low combustion temperature and high combustion rate.

[0065] Comparative Example 1

[0066] The difference between Comparative Example 1 and Example 1 is that 2PbCO3·Pb(OH)2 is not added, while the remaining proportions and preparation methods are the same as in Example 1.

[0067] Experimental Example: Carbon Dioxide Laser Ignition Experiment

[0068] The gas-generating agents prepared in Example 1 and Comparative Example 1 were used in this experiment. To maintain the same sample mass, the mass ratio of Comparative Example 1 to Example 1 was 9:10. To observe the specific combustion of the gas-generating agent, a CO2 laser igniter was used to ignite the propellant. The combustion process was recorded using a Photron FASTCAM Mini UX100 high-speed camera with a resolution of 1280×1024 and a frame rate of 500fps. A self-made R-type thermocouple was used to measure the combustion temperature, and samples were taken at distances of 0 cm, 1 cm, and 2 cm from the propellant column, corresponding to sampling points Po-1, Po-2, and Po-3. Combustion residues were collected for SEM and XRD analysis to investigate their composition and microstructure.

[0069] Table 1. Thermocouple temperature measurement results of sampling points Po-1, Po-2, and Po-3 of the gas-generating agent.

[0070]

[0071] Thermocouple measurements show that the temperature of the gas-generating agent decreased significantly after the addition of basic lead carbonate, indicating that basic lead carbonate has excellent cooling effect.

[0072] Closed-loop explosion experiment

[0073] This method uses the differential method of a closed-circuit burner to calculate the combustion rate of the embodiments and comparative examples. The specific calculation steps are as follows:

[0074] S1: Pt curve of the gas-producing agent combustion measured by a closed-circuit igniter

[0075] S2: The internal ballistic parameters of the propellant charge were calculated using internal ballistics formulas. The specific results are shown in the table below.

[0076] S3: The measured pressure can be converted into its corresponding gunpowder combustion percentage ψ using formula (1), that is, the Pt curve is converted into a ψ-t curve. In the formula, x and λ are the propellant shape coefficients, which can be obtained through the propellant shape function. e is the combustion thickness, e l This represents the original height of the medicine column.

[0077]

[0078] S4: The curve of relative combustion layer thickness z versus time t can be obtained by formula (2), i.e., the zt curve. The zt curve is converted into the et curve by formula (3).

[0079]

[0080] According to the definition of combustion rate (4), the relationship between combustion rate u and time is obtained by differentiation.

[0081]

[0082] from Figure 1 As can be seen, the comparative and example samples prepared according to the present invention are uniformly mixed, and their physical states remain unchanged. From... Figure 2 As can be seen from the example, after adding basic lead carbonate, the flame height decreased significantly, and the combustion became more stable, with the flame height remaining essentially constant after 1 second. From... Figure 3 As can be seen, the combustion rate of the embodiment is significantly improved. From Figure 4 As can be seen from the examples, the degree of agglomeration of the combustion residue is significantly reduced, exhibiting a spherical core-shell structure.

[0083] In summary, lead salts reduce the combustion temperature of 5-aminotetrazole gas-generating agents while significantly increasing the combustion rate, indicating that lead salts possess good catalytic and cooling properties, and can also reduce the agglomeration of combustion residues.

[0084] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A lead salt-modified 5-aminotetrazolium-based gas-generating agent with low combustion temperature and high combustion rate, characterized in that: It includes 5-aminotetrazole, strontium nitrate, and lead salt, with lead salt accounting for 5% to 10% by mass.

2. The low-burning-temperature, high-burning-rate lead salt-modified 5-aminotetrazolium-based gas-generating agent according to claim 1, characterized in that: The lead salt is basic lead carbonate and / or lead carbonate.

3. The low-burning-temperature, high-burning-rate lead salt-modified 5-aminotetrazolium-based gas-generating agent according to claim 1, characterized in that: The 5-aminotetrazole and strontium nitrate are mixed in a zero oxygen balance ratio.

4. The method for preparing the low-burning-temperature, high-burning-rate lead salt-modified 5-aminotetrazolium-based gas-generating agent according to any one of claims 1-3, characterized in that: Includes the following steps: S1: Mix 5-aminotetrazolium, strontium nitrate, lead salt, and solvent evenly using a wet ball milling method; S2: After ball milling, place the ball in an oven to allow the solvent to evaporate completely. S3: Use a standard sieve to sieve the dried sample to obtain gas-generating agent powder; S4: The gas-generating agent powder is pressed into a column shape using a press machine to obtain the lead salt modified 5-aminotetrazolium gas-generating agent product with low combustion temperature and high combustion rate.

5. The method for preparing the low-burning-temperature, high-burning-rate lead salt-modified 5-aminotetrazolium-based gas-generating agent according to claim 4, characterized in that: The solvent in step S1 is one or more of anhydrous ethanol, acetone, dichloromethane, and water.

6. The method for preparing the low-burning-temperature, high-burning-rate lead salt-modified 5-aminotetrazolium-based gas-generating agent according to claim 4, characterized in that: In step S1, anhydrous ethanol is used as the solvent.

7. The method for preparing the low-burning-temperature, high-burning-rate lead salt-modified 5-aminotetrazolium-based gas-generating agent according to claim 4, characterized in that: The volume ratio of the solvent to the total volume of 5-aminotetrazole, strontium nitrate, and lead salt is (2-4):

1.

8. The method for preparing the low-burning-temperature, high-burning-rate lead salt-modified 5-aminotetrazolium-based gas-generating agent according to claim 4, characterized in that: In step S1, the ball mill rotates at a speed of 200–400 r / min and the milling time is 2–4 h.

9. The method for preparing the low-burning-temperature, high-burning-rate lead salt-modified 5-aminotetrazolium-based gas-generating agent according to claim 4, characterized in that: In step S2, the oven temperature is 50–100°C and the time is 4–10 hours.

10. The method for preparing the low-burning-temperature, high-burning-rate lead salt-modified 5-aminotetrazolium-based gas-generating agent according to claim 4, characterized in that: The standard sieve in step S3 is an 80-120 mesh sieve, which yields powder with a particle size of less than 180 μm. Preferably, step S4 uses a mold with a diameter of 10-25 mm for pressing, applies a pressure of 1-2 MPa, and holds the pressure for 1-3 minutes.

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