Preparation method of nano pentaaminotetrazole particles

Abstract

The invention provides a preparation method of nano pentaaminotetrazole particles, which comprises the following steps: adding pentaaminotetrazole into a solvent, sealing, and heating to dissolve the pentaaminotetrazole; the dissolved pentaamino tetrazole solution is subjected to oscillation; s2, the solution vibrated in the step S2 is sucked into an injector in an electrostatic spinning device to serve as electrospinning liquid for electrostatic spinning, the voltage in the electrostatic spinning process is 5-20 kV, the receiving distance is 10-20 cm, and the flow velocity of the electrospinning liquid is 0.2-1.0 mL / h; and collecting a sample on a receiving device in the electrostatic spinning device in the step S3 to obtain the nano pentaaminotetrazole particles. The nano pentaamino tetrazole particles prepared by adopting electrostatic spinning are low in cost, small in difficulty and high in yield, and the prepared nano pentaamino tetrazole particles are all of nano size and are uniform.

Description

Technical Field

[0001] The invention belongs to the field of energetic material preparation, and in particular relates to a method for preparing nanometer pentaaminotetrazole particles. Background Art

[0002] Pentaaminotetrazolyl (5AT) is a high-nitrogen, high-energy-insensitive, and easy-to-synthesize energetic material that has attracted much attention in the field of solid propellants. However, its pyrolysis temperature in the low-temperature range is relatively high, which reduces the gas products generated during the pyrolysis process.

[0003] Nanoparticles can absorb heat faster due to their small size and large specific surface area, and make it easier for heat to be conducted and distributed over the entire particle surface, thereby achieving more uniform and rapid heating, promoting an increase in reaction rate and uniformity of the reaction process.

[0004] In the prior art, pentaaminotetrazole of smaller size can only be obtained through physical grinding and chemical recrystallization. However, the samples prepared by the above methods still have disadvantages such as uneven size, large size, and poor performance, which limits its further application. Summary of the invention

[0005] In view of this, the present invention aims to overcome the defects in the prior art and proposes a method for preparing nanometer pentaaminotetrazole particles.

[0006] To achieve the above object, the technical solution of the present invention is achieved as follows:

[0007] A method for preparing nano pentaaminotetrazole particles comprises the following steps:

[0008] S1: Add pentaaminotetrazole into a solvent, seal it, and heat it to dissolve it;

[0009] S2: shaking the dissolved pentaaminotetrazolyl solution;

[0010] S3: The solution after the shock in step S2 is sucked into a syringe in an electrospinning device as an electrospinning liquid for electrospinning. During the electrospinning process, the voltage is 5 to 20 kV, the receiving distance is 10 to 20 cm, and the flow rate of the electrospinning liquid is 0.2 to 1.0 mL / h;

[0011] S4: Collect the sample on the receiving device in the electrospinning device in step S3 to obtain nano pentaaminotetrazole particles.

[0012] Preferably, the solvent in step S1 is ethanol.

[0013] Preferably, the mass concentration of the pentaaminotetrazole solution in step S1 is 0.5-4 mg / mL.

[0014] Preferably, the nanometer pentaaminotetrazolyl particles obtained in step S5 are dried at 40 to 90° C. for 1 to 3 hours and then stored in a sealed manner.

[0015] Preferably, in step S1, pentaaminotetrazole and ethanol solvent need to be heated continuously in a constant temperature water bath heating box for 10 to 30 minutes.

[0016] Preferably, in step S2, a vortex oscillator is used for oscillation, and the rotation speed of the vortex oscillator is 100-500 r / min.

[0017] Compared with the prior art, the present invention has the following advantages:

[0018] (1) The nanometer pentaaminotetrazolyl particles prepared by electrospinning in the present invention have low cost, low difficulty and high yield, and the prepared nanometer pentaaminotetrazolyl particles are all nanometer-sized and uniform;

[0019] (2) The nano-pentaaminotetrazolyl particles prepared by electrospinning have better thermal decomposition effect and are expected to be mixed with oxidants as propellants and be more widely used. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 : is an electron microscope comparison of pentaaminotetrazolyl particles (the left picture is the pentaaminotetrazolyl particles prepared in Comparative Example 1, the middle picture is the pentaaminotetrazolyl particles prepared in Example 1, and the right picture is the pentaaminotetrazolyl particles prepared in Comparative Example 2);

[0021] Figure 2 This is a comparison diagram of the TGA curves of pentaaminotetrazolyl particles;

[0022] Figure 3 This is the relationship curve between the activation energy of pentaaminotetrazole particles and the conversion rate. DETAILED DESCRIPTION

[0023] Unless otherwise defined, the technical terms used in the following examples have the same meanings as those generally understood by those skilled in the art to which the present invention belongs. The test reagents used in the following examples, unless otherwise specified, are all conventional biochemical reagents; the experimental methods, unless otherwise specified, are all conventional methods.

[0024] The present invention will be described in detail below with reference to the embodiments.

[0025] Example 1

[0026] In this embodiment, nanometer pentaaminotetrazole particles were prepared by high temperature dissolution and electrospinning, and their morphology was observed by scanning electron microscopy. In addition, their pyrolysis behavior was analyzed by thermogravimetric analysis. The specific steps are as follows:

[0027] (1) Prepare a 2.5 mg / mL solution of pentaaminotetrazole and anhydrous ethanol and weigh the sample;

[0028] (2) Then, the solution prepared at a concentration of 2.5 mg / mL was placed in a sealed centrifuge tube and heated in a constant temperature water bath at 55° C. to increase the solubility of pentaaminotetrazole in ethanol;

[0029] (3) The heated solution was oscillated on a vortex oscillator at a speed of 400 r / min for 5 min to mix it evenly;

[0030] (4) Then, 5 mL of the mixed solution was placed in the syringe of the electrospinning device as the electrospinning liquid for electrospinning, and the working voltage was set to 8 kV, the receiving distance was 15 cm, the liquid flow rate was 0.4 mL / h, and the total working time was 5 h;

[0031] (5) Finally, the nanometer pentaaminotetrazole particles on the receiving device are scraped and dried at 90° C. for 3 h and then stored in a sealed manner.

[0032] Example 2

[0033] In this embodiment, nanometer pentaaminotetrazole particles were prepared by high temperature dissolution and electrospinning, and their morphology was observed by scanning electron microscopy. In addition, their pyrolysis behavior was analyzed by thermogravimetric analysis. The specific steps are as follows:

[0034] (1) Prepare a 0.5 mg / mL solution of pentaaminotetrazole and anhydrous ethanol and weigh the sample;

[0035] (2) Then, the solution prepared at a concentration of 0.5 mg / mL was placed in a sealed centrifuge tube and heated in a constant temperature water bath at 40°C;

[0036] (3) The heated solution was oscillated on a vortex oscillator at a speed of 400 r / min for 10 min to mix it evenly;

[0037] (4) Then, 5 mL of the mixed solution was placed in the syringe of the electrospinning device as the electrospinning liquid for electrospinning, and the working voltage was set to 5 kV, the receiving distance was 10 cm, the liquid flow rate was 0.2 mL / h, and the total working time was 5 h;

[0038] (5) Finally, the nanometer pentaaminotetrazole particles on the receiving device are scraped and dried at 90° C. for 3 h and then stored in a sealed manner.

[0039] Example 3

[0040] In this embodiment, nanometer pentaaminotetrazole particles were prepared by high temperature dissolution and electrospinning, and their morphology was observed by scanning electron microscopy. In addition, their pyrolysis behavior was analyzed by thermogravimetric analysis. The specific steps are as follows:

[0041] (1) Prepare a 4 mg / mL solution of pentaaminotetrazole and anhydrous ethanol and weigh the sample;

[0042] (2) Then, the solution prepared at a concentration of 4 mg / mL was placed in a sealed centrifuge tube and heated in a constant temperature water bath at 60°C;

[0043] (3) The heated solution was oscillated on a vortex oscillator at a speed of 400 r / min for 10 min to mix it evenly;

[0044] (4) Then, 5 mL of the mixed solution was placed in the syringe of the electrospinning device as the electrospinning liquid for electrospinning, and the working voltage was set to 20 kV, the receiving distance was 20 cm, the liquid flow rate was 1 mL / h, and the total working time was 5 h;

[0045] (5) Finally, the nanometer pentaaminotetrazole particles on the receiving device are scraped and dried at 40° C. for 3 h and then stored in a sealed manner.

[0046] Comparative Example 1

[0047] In this comparative example, nano pentaaminotetrazole particles were prepared by high temperature dissolution and electrostatic spinning, wherein pentaaminotetrazole and anhydrous ethanol were mixed to prepare a 6 mg / mL solution, and the remaining steps were the same as those in Example 1.

[0048] Comparative Example 2

[0049] In this comparative example, pentaaminotetrazole was ground by ball milling. The ball milling process was as follows: 5AT sample was mixed with anhydrous ethanol in a ratio of 1:3 and then placed in an agate grinding jar. An appropriate amount of grinding balls were added to the grinding jar and sealed and installed. A planetary centrifugal ball mill was used to wet grind at a speed of 150 r / min for 24 hours. Subsequently, the sample was placed in an oven and baked for 8 hours to evaporate the anhydrous ethanol. Finally, the sample was finely screened through a 180-mesh sieve to ensure that the obtained sample met the requirements of subsequent experiments.

[0050] The pentaaminotetrazolyl particles obtained in Comparative Examples 1 and 2 and the electrospun nano pentaaminotetrazolyl particles obtained in Example 1 were distributed on a conductive adhesive of 5 mm × 5 mm size for scanning electron microscopy photography; in addition, the three pentaaminotetrazolyl particle samples were subjected to TGA testing to explore the main pyrolysis process of electrospun nanoparticles. For each test, 1 ± 0.2 mg of the sample was placed in an alumina crucible and tested at three heating rates of 5, 10 and 15 ° C / min in a nitrogen atmosphere to obtain the relationship between the mass and temperature of the sample between 100 and 400 ° C.

[0051] The activation energy trends of pentaaminotetrazole samples prepared by ball milling and electrospinning processes were calculated using two equal conversion methods, FWO and KAS, to describe the pyrolysis process of the samples.

[0052] The formula used in the above calculation process is as follows:

[0053] OFW method: logβ=logAE α / (Rg(α))-2.315-0.4567E α / RT;

[0054] KAS method: ln(β / T 2 )=ln[AR / (E α g(α))]-E α / RT.

[0055] Specific results such as Figure 1-Figure 3 shown.

[0056] Depend on Figure 1 It can be seen that the scale of the SEM image of the ball-milled sample of Comparative Example 1 is 10 μm, the sample morphology is irregular, and the difference is large; the middle figure uses a solution concentration of 2.5 mg / mL for electrospinning preparation, and the scale of the SEM image is 1 μm. It can be seen that they are all nano-scale 5AT spherical particles with uniform size distribution; the right figure uses a sample prepared at a concentration of 6 mg / mL, and the scale of the SEM image is 10 μm. The sample is similar to an irregular sphere and has a large difference.

[0057] Depend on Figure 2It can be seen that the temperature at which the ball-milled sample begins to decompose is earlier than that of the sample prepared by the preparation method of the present invention, and the temperature at which the ball-milled sample reaches the fastest decomposition rate is about 222°C, and the temperature at which the sample prepared by electrospinning reaches the fastest decomposition rate is about 232°C, which is about 10°C different from each other. This temperature difference indicates that the sample prepared by the preparation method of the present invention has an advantage in thermal stability. Although the sample particles prepared by the preparation method of the present invention are finer, the reaction process shows higher stability and the thermal decomposition temperature does not drop significantly. This phenomenon shows that the preparation method of the present invention can improve the thermal stability of 5AT, so that the sample can maintain a relatively stable state during the thermal decomposition process. In addition, the decomposition end temperature of the 6mg / L electrospun sample is about 30°C earlier than that of the 2.5mg / L electrospun sample, showing a lower decomposition temperature range. The two have higher thermal stability than the latter. On the basis of reaching nano-scale particles, the 2.5mg / L electrospun sample has higher practicality, which is of great significance for the application safety and performance optimization of 5AT, especially in occasions where extreme temperature conditions are required.

[0058] Depend on Figure 3 It can be seen that the apparent activation energy of the three samples changes with the conversion rate. Due to the instability in the initial and final stages of the reaction, the range of 0.3<α<0.8 was selected for comparative analysis. The apparent activation energies of the ball-milled samples obtained by the FWO method and the KAS method were 156.6 kJ / mol and 156.2 kJ / mol, respectively. The apparent activation energies of the samples prepared by electrospinning obtained by 6 mg / L were 143.3 kJ / mol and 142.1 kJ / mol, respectively, while the apparent activation energies of the samples prepared by electrospinning obtained by 2.5 mg / L were 148.1 and 147.3.2 kJ / mol, respectively. The results obtained by the two kinetic calculation methods are not much different, which shows the accuracy of the calculation results. At the same time, the activation energy obtained by the three sample preparation methods is only about 8-9 kJ / mol, indicating that the nano-5AT prepared by electrospinning still has good thermal stability. At the same time, the thermal stability of the electrospun sample of 2.5 mg / L is better than that of the electrospun sample of 6 mg / L.

[0059] Therefore, the 5AT sample prepared by the preparation method of the present invention not only successfully reached the fine size of the nanometer level, the spherical particles of the sample prepared by the preparation method of the present invention were less than 1μm, and showed a high degree of structural uniformity, and the spherical particle size distribution was uniform. More importantly, the nanofibers prepared by this method showed excellent thermal stability and safety, making them more attractive in potential applications. The meticulous control and precise technical adjustments in the preparation process of this nanofiber ensure that its performance remains stable under extreme conditions, while reducing the risk of thermal sensitivity that may increase due to size reduction. These characteristics make the 5AT nanofibers prepared by the preparation method of the present invention a very promising candidate material in the field of high-energy materials, especially in applications where safety is critical.

[0060] 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 principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing nanometer pentaaminotetrazole particles, characterized in that: The steps include: S1: Add pentaaminotetrazole into a solvent, seal it, and heat it to dissolve it; S2: shaking the dissolved pentaaminotetrazolyl solution; S3: The solution after the shaking in step S2 is sucked into a syringe in the electrospinning device as an electrospinning liquid for electrospinning. During the electrospinning process, the voltage is 5 to 20 kV, the receiving distance is 10 to 20 cm, and the flow rate of the electrospinning liquid is 0.2 to 1.0 mL / h; S4: Collect the sample on the receiving device in the electrospinning device in step S3 to obtain nano pentaaminotetrazole particles.

2. The method for preparing nanometer pentaaminotetrazolyl particles according to claim 1, characterized in that: The solvent in step S1 is ethanol.

3. The method for preparing nanometer pentaaminotetrazolyl particles according to claim 1, characterized in that: The mass concentration of the pentaaminotetrazole solution in step S1 is 0.5-4 mg / mL.

4. The method for preparing nanometer pentaaminotetrazolyl particles according to claim 1, characterized in that: The nanometer pentaaminotetrazolyl particles obtained in step S5 are dried at 40-90° C. for 1-3 hours and then sealed and stored.

5. The method for preparing nanometer pentaaminotetrazolyl particles according to claim 1, characterized in that: In step S1, pentaaminotetrazole and ethanol solvent need to be heated continuously in a constant temperature water bath heating box for 10 to 30 minutes.

6. The method for preparing nanometer pentaaminotetrazolyl particles according to claim 1, characterized in that: In the step S2, a vortex oscillator is used for oscillation, and the rotation speed of the vortex oscillator is 100-500 r / min.

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