Method for synthesizing copper azide based on ink-jet printing and application thereof

Abstract

The invention discloses a method for synthesizing copper azide based on ink-jet printing and application of the method, and belongs to the technical field of energetic materials. The method is based on an ink-jet printing technology, sodium azide ink and copper salt ink are prepared respectively, the surface tension and viscosity of the sodium azide ink are adjusted through a binder and a surfactant, the surface tension of the copper salt ink is adjusted through the mass ratio of water to ethylene glycol, a sodium azide layer and copper salt are printed in sequence, and copper azide is obtained through an in-situ reaction. According to the method, the copper azide initiating explosive can be printed on the medium in situ, complete hand-free operation in the charging process is achieved, and danger in the manual copper azide charging process is avoided. And meanwhile, quantitative copper salt is printed by ink-jet printing, so that the generated copper azide / cuprous azide can be controlled.

Description

Technical Field

[0001] The present application belongs to the technical field of energetic materials, and specifically relates to a method for synthesizing copper azide based on inkjet printing and its application. Background Art

[0002] In recent years, in order to meet the requirements of miniaturization and intelligence of weapons and equipment, pyrotechnics are developing towards MEMS (Micro Electro-Mechanical Systems) pyrotechnics with multiple functions, miniature structures and sequence integration. This requires the energy conversion element and the charge structure size to be in the micron level. Therefore, this puts higher requirements on the charge: it has a large detonation capacity and a small charge amount. Traditional detonators such as lead azide and lead styphnate cannot meet the energy output requirements and are not suitable for MEMS pyrotechnics.

[0003] Compared with lead azide, copper azide has higher detonation ability and is more environmentally friendly, making it a suitable choice for MEMS pyrotechnics, but its high electrostatic sensitivity (E 50 =0.05mJ) brings great safety hazards to the preparation and charging process, limiting its application development.

[0004] At present, there are many methods to achieve in-situ synthesis of azides, such as gas-solid in-situ method, electrochemical method, electrospinning method and direct writing technology. However, the gas-solid method has harsh reaction conditions and long reaction time. The utilization rate of hydrazine acid is low and there is a risk of environmental pollution. The electrochemical method will produce by-products such as copper oxide and cuprous azide. Electrospinning technology and direct writing technology are only different in the preparation method of precursors, but the in-situ azidation method has not deviated from the original method and has the same problems as the gas-solid method and electrochemical method.

[0005] Inkjet printing has been shown to be beneficial for the small-scale deposition of functional inks, making up for the inability to perform sub-millimeter spatial control in current processes. Domestic and foreign scholars have preliminarily explored the research on micro-charging of energetic materials and micro-manufacturing of energetic devices at high precision, complex patterns, and micro-nano levels. However, due to the high sensitivity of detonators, there are no reports on the successful in-situ charging of detonators using inkjet printing methods. Summary of the invention

[0006] 1. Purpose of the Invention

[0007] The purpose of the present application is to provide a method for synthesizing copper azide based on inkjet printing and its application. Through the formulation design of the ink, highly sensitive copper azide is successfully synthesized by inkjet printing, which is applied to the preparation of pyrotechnics, and the safe in-situ charging of copper azide detonators can be achieved.

[0008] 2. Technical solution

[0009] In order to solve the above problems, the technical solutions adopted in this application are as follows:

[0010] The present application provides a method for synthesizing copper azide based on inkjet printing, the method comprising the following steps:

[0011] S1, configure ink

[0012] A sodium azide ink is prepared, wherein the sodium azide ink comprises sodium azide, water, polyvinyl pyrrolidone, sodium dodecylbenzene sulfonate and ethylene glycol; the surface tension of the sodium azide ink is controlled to be 36.0-45.0 mN / m, and the viscosity is controlled to be 4.0-9.0 cps; the content of sodium azide in the sodium azide ink is 0.1-0.3 g / mL; in the sodium azide ink, water is a solvent, polyvinyl pyrrolidone is a binder, sodium dodecylbenzene sulfonate is a surfactant, and ethylene glycol is used to increase the viscosity;

[0013] A copper salt ink is prepared, wherein the copper salt ink comprises copper salt, water and ethylene glycol; the surface tension of the copper salt ink is controlled to be 36.0 to 42.0 mN / m, and the viscosity is controlled to be 4.0 to 12.0 cPs; and the content of the copper salt in the copper salt ink is 0.1 to 1.0 g / mL;

[0014] S2, inkjet printing

[0015] On a printing medium, firstly, a plurality of sodium azide layers are printed using sodium azide ink, and then copper salt is printed on the printed sodium azide layers using copper salt ink;

[0016] S3, vacuum drying

[0017] The product obtained in step S2 is dried under vacuum.

[0018] Furthermore, in the sodium azide ink, the mass percentage of polyvinyl pyrrolidone is 2.0% to 6.0%; the mass percentage of sodium dodecylbenzene sulfonate is 0.1% to 0.3%; and the mass percentage of ethylene glycol is 25.0% to 35.0%.

[0019] Furthermore, the surface tension of the sodium azide ink is 38.0-42.0 mN / m, and the viscosity is 6.0-9.0 cPs.

[0020] Furthermore, in the copper salt ink, the copper salt includes copper nitrate.

[0021] Furthermore, in the copper salt ink, the mass ratio of ethylene glycol to water is (0.3-2):1.

[0022] Furthermore, the surface tension of the copper salt ink is 36.0-42.0 mN / m, and the viscosity is 4.0-12.0 cPs.

[0023] Furthermore, the surface tension of the sodium azide ink is 38.0-42.0 mN / m, and the viscosity is 6.0-9.0 cPs; the surface tension of the copper salt ink is 36.0-42.0 mN / m, and the viscosity is 9.0-10.0 cPs.

[0024] Furthermore, in the above S2 inkjet printing, when the printing area is the same, the number of printed layers of sodium azide and the number of printed layers of copper salt are controlled so that the molar number of printed sodium azide is slightly greater than the molar number of copper salt.

[0025] Furthermore, in the above S2 inkjet printing, the volume of a single ink drop is 10 pL.

[0026] Furthermore, in the above-mentioned S2 inkjet printing, there is no special limitation on the printing medium, and it can be an pyrotechnic component of any structure, such as a semiconductor bridge.

[0027] Furthermore, in the above-mentioned vacuum drying in S3, the product obtained in S2 is placed in a vacuum oven and dried at 60° C. for 6 to 12 hours to ensure that the solvent is fully volatilized.

[0028] Furthermore, the above-mentioned method for synthesizing copper azide based on inkjet printing uses Fujifilm Dimatix material printer DMP-2850 for inkjet printing. Fujifilm Dimatix material printer DMP-2850 is a DOD piezoelectric driven inkjet printer with the functions of adjusting the print head temperature, platen temperature, emission voltage, printing height, ink drop spacing and repeated printing.

[0029] Furthermore, the printing nozzle diameter of the above-mentioned Fujifilm Dimatix material printer DMP-2850 is 21 μm.

[0030] Furthermore, the above-mentioned Fujifilm Dimatix material printer DMP-2850 has 16 nozzles, which are driven by the piezoelectric elements of the Dimatix printer, which are much smaller than most laboratory-developed inkjet printers (eg, typically 60 to 90 μm in diameter).

[0031] Furthermore, the jetting voltage of the above-mentioned Fujifilm Dimatix material printer DMP-2850 is 15 to 16.5 V, the jetting frequency is 5 kHz, and the inkjet spacing is 15 to 20 μm.

[0032] The present application also provides an application of the above-mentioned method for synthesizing copper azide based on inkjet printing in the preparation of pyrotechnic components, thereby realizing the safe in-situ charging of copper azide detonating explosives.

[0033] Further, the above application includes printing synthetic copper azide on components, such as semiconductor bridges.

[0034] The present application also provides an energetic pyrotechnic component prepared by the above application.

[0035] The present application also provides an energetic pyrotechnic device, comprising the energetic pyrotechnic device component described above.

[0036] 3. Beneficial effects

[0037] Compared with the prior art, the present application has the following beneficial effects:

[0038] (1) The present application provides a method for synthesizing copper azide based on inkjet printing and its application, wherein a binder and a surfactant are used to adjust the surface tension and viscosity of sodium azide ink, and the mass ratio of ethylene glycol and water is used to adjust the surface tension and viscosity of silver salt ink, and sodium azide and copper salt are printed successively, and copper azide is obtained by in-situ reaction, and the surface tension of sodium azide ink is controlled to be 38.0-42.0 mN / m, and the viscosity is 6.0-9.0 cPs; the surface tension of the copper salt ink is controlled to be 36.0-42.0 mN / m, and the viscosity is 4.0-10.0 cPs, and the sodium azide ink and the silver salt ink can be stored at a low temperature of 2-6°C for one month without deterioration, and the ink has good stability and is not affected by normal temperature use. In addition, the shape and size of the copper azide (priming explosive) synthesized based on inkjet printing are controllable, especially as a primary explosive, the characteristic size can be controlled to be below 1 mm, and the thickness of the primary explosive can be adjusted according to the number of printed layers, which increases the flexibility of the primary explosive charge while ensuring safety.

[0039] (2) The present application provides a method for synthesizing copper azide based on inkjet printing and its application. The inkjet printing method is used to in-situ print the synthesized copper azide (initiator) on the pyrotechnic components (printing medium). The charging process is completely hands-free, avoiding the dangers of manual silver azide charging.

[0040] (3) The present application provides a method for synthesizing copper azide based on inkjet printing and its application, which adopts Fujifilm Dimatix material printer DMP-2850 inkjet printing, and the amount of each drop is controlled at the pL level. The amount of droplets can be controlled according to the size of the pattern, thereby controlling the amount of synthesized silver azide. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 This is a printing example of copper azide;

[0042] Figure 2 is a SEM image of copper azide;

[0043] Figure 3is a SEM image of cuprous azide;

[0044] Figure 4 is the FT-IR image of copper azide;

[0045] Figure 5 This is the FT-IR image of cuprous azide. DETAILED DESCRIPTION

[0046] The present application is further described below in conjunction with specific embodiments.

[0047] It should be noted that the terms such as "upper", "lower", "left", "right", "middle", etc. cited in this specification are only for the convenience of description and are not used to limit the scope of implementation. Changes or adjustments to their relative relationships should be regarded as the scope of implementation of this application without substantially changing the technical content.

[0048] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this application belongs; the term "and / or" used herein includes any and all combinations of one or more of the associated listed items.

[0049] If the specific conditions are not specified in the examples, the experiments were carried out under conventional conditions or conditions recommended by the manufacturer. If the manufacturers of the reagents or instruments are not specified, they are all conventional products that can be purchased commercially.

[0050] As used herein, the term "about" is used to provide flexibility and imprecision associated with a given term, measurement or value. The degree of flexibility for a particular variable can be easily determined by one skilled in the art.

[0051] As used herein, the term "at least one of" is intended to be synonymous with "one or more of." For example, "at least one of A, B, and C" expressly includes only A, only B, only C, and combinations of each thereof.

[0052] Concentration, amount and other numerical data can be presented in range format herein.It should be understood that such range format is only used for convenience and simplicity, and should be flexibly interpreted as not only including the numerical value clearly described as range limit, but also including all single numerical values ​​or sub-ranges contained in the range, just as each numerical value and sub-range are clearly described.For example, the numerical range of about 1 to about 4.5 should be interpreted as not only including the limit value of 1 to about 4.5 clearly described, but also including single numerals (such as 2,3,4) and sub-ranges (such as 1 to 3,2 to 4, etc.).The same principle is applicable to the scope of only narrating a numerical value, such as "less than about 4.5", which should be interpreted as including all the above-mentioned values ​​and ranges.In addition, no matter how the breadth of the described range or feature is, this explanation should be applicable.

[0053] Example 1

[0054] This embodiment provides a method for synthesizing copper azide based on inkjet printing and its application. Specifically, it includes:

[0055] S1, configure ink

[0056] To prepare sodium azide ink, add 2g PVP (polyvinyl pyrrolidone) and 0.06g SDBS (sodium dodecylbenzene sulfonate) to 20mL of deionized water. After mixing evenly, add 0.5mL ethylene glycol and 0.3g sodium azide to 1mL of the solution to prepare 0.2g / mL sodium azide ink; the surface tension is 40mN / m and the viscosity is 8.4cPs;

[0057] Prepare copper salt ink, take 20mL ethylene glycol and add 10mL deionized water, after ultrasonic mixing, take 1.57g copper nitrate hexahydrate, add the mixed solvent to 1mL, and prepare the copper nitrate ink with a concentration of 1g / mL; the surface tension is 38mN / m, and the viscosity is 9cPs;

[0058] S2, inkjet printing

[0059] Sodium azide ink was loaded into DMP-2850, and the printing parameters were set as follows: voltage 16.5 V, frequency 5 kHz, nozzle temperature 30 °C, ink drop spacing 20 μm, voltage rise / fall within 1 μs, pulse duration ~6.4 μs, 100% printing potential;

[0060] In this embodiment, the printing medium is an ignition bridge; the printing area is 0.6 mm × 0.6 / 0.8 mm, the number of layers is 20, and then the copper nitrate ink cartridge is replaced (note that the ink drop collector should also be replaced at the same time) to print 5 layers to form a reaction, and print on the ignition bridge (such as Figure 1 ).

[0061] In the embodiment, the molar number of printed copper nitrate is controlled to be slightly smaller than the molar number of sodium azide, and a black copper azide sample is obtained, and its SEM image is as follows: Figure 2 ; The molar number of printed copper nitrate is controlled to be greater than one molar number of sodium azide, and a white cuprous azide sample is obtained, and its SEM image is Figure 3 .

[0062] S3, vacuum drying

[0063] The in-situ printed ignition bridge containing Cu(N3)2 was placed in a vacuum oven and dried at 60°C for 12 h to obtain the finished product.

[0064] Figure 4 and Figure 5 These are the FT-IR images of copper azide and cuprous azide, Figure 4 The peak position is at 2073.75cm -1 The position is the azide root peak of copper azide.

[0065] Example 2

[0066] Take 20mL of deionized water and add 0.5g / 1.5g of PVP. It is found that the change of PVP concentration has little effect on the surface tension, but mainly affects the viscosity. The viscosity increases from 4.23cPs to 7.10cPs. The other conditions are the same as those in Example 1, and the copper azide product is successfully printed.

[0067] Example 3

[0068] The solvent composition of ethylene glycol: deionized water was changed from 20:10 to 10:20. After adding copper nitrate, the surface tension decreased and the viscosity decreased from 9 cPs to 6.2 cPs. When the other conditions were the same as in Example 1, printing was also possible and the copper azide product was successfully printed.

[0069] Comparative Example 1

[0070] Sodium dodecyl sulfate (SDS) was used as a surfactant instead of sodium dodecylbenzene sulfonate. The other conditions were the same as in Example 1. It was found that sodium azide produced precipitation after contact with sodium dodecyl sulfate, and it was impossible to prepare a full-liquid ink. Therefore, it was concluded that sodium dodecyl sulfate was not suitable as a surfactant in sodium azide ink.

[0071] Comparative Example 2

[0072] No surfactant was added to the sodium azide ink, and the other configurations were the same as those of the sodium azide ink in Example 1. The surface tension of the sodium azide ink was greater than 50 mN / m, and only a very small amount of sodium azide could be printed. The reason was that the surface tension was too large, and the applied voltage was insufficient to overcome the surface tension of the ink, so the ink could not break at the nozzle to form ink droplets, and thus could not be printed.

[0073] Comparative Example 3

[0074] When the solvent water in Example 1 is replaced with ethanol, the surface tension is less than 30 mN / m. At this time, the printing parameters cannot control the ink droplets, and the ink flows out continuously at the nozzle without forming droplets.

Claims

1. A method for synthesizing copper azide based on inkjet printing, characterized in that: The method comprises the following steps: S1, configure ink A sodium azide ink is prepared, wherein the sodium azide ink comprises sodium azide, water, polyvinyl pyrrolidone, sodium dodecylbenzene sulfonate and ethylene glycol; the surface tension of the sodium azide ink is 36.0 to 45.0 mN / m, and the viscosity is 4.0 to 9.0 cps; and the content of sodium azide in the sodium azide ink is 0.1 to 0.3 g / mL; A copper salt ink is prepared, wherein the copper salt ink contains copper salt, water and ethylene glycol; the surface tension of the copper salt ink is 36.0 to 42.0 mN / m, and the viscosity is 4.0 to 12.0 cPs; and the content of copper salt in the copper salt ink is 0.1 to 1.0 g / mL; S2, inkjet printing On a printing medium, firstly, a plurality of sodium azide layers are printed using sodium azide ink, and then copper salt is printed on the printed sodium azide layers using copper salt ink; S3, vacuum drying The product obtained in step S2 is dried under vacuum.

2. A method for synthesizing copper azide based on inkjet printing according to claim 1, characterized in that: In the sodium azide ink, the mass percentage of polyvinyl pyrrolidone is 2.0% to 6.0%, the mass percentage of sodium dodecylbenzene sulfonate is 0.1% to 0.3%, and the mass percentage of ethylene glycol is 25.0% to 35.0%.

3. A method for synthesizing copper azide based on inkjet printing according to claim 2, characterized in that: The copper salt includes copper nitrate.

4. The method for synthesizing copper azide based on inkjet printing according to claim 3, characterized in that: The mass ratio of ethylene glycol to water in the copper salt ink is (0.3-2):

1.

5. The method for synthesizing copper azide based on inkjet printing according to claim 4, characterized in that: The surface tension of the sodium azide ink is 38.0-42.0 mN / m, and the viscosity is 6.0-9.0 cPs; the surface tension of the copper salt ink is 36.0-42.0 mN / m, and the viscosity is 4.0-12.0 cPs.

6. The method for synthesizing copper azide based on inkjet printing according to claim 5, characterized in that: In the S2 inkjet printing, when the printing area is the same, the molar number of printed sodium azide is slightly greater than the molar number of copper salt.

7. The method for synthesizing copper azide based on inkjet printing according to claim 6, characterized in that: In the S2 inkjet printing, a Fujifilm Dimatix material printer DMP-2850 is used for inkjet printing.

8. Use of the method for synthesizing copper azide based on inkjet printing as described in any one of claims 1 to 7 in the preparation of pyrotechnic components.

9. The pyrotechnic components prepared in the application of claim 8.

10. An energetic explosive device, characterized in that: The energetic pyrotechnic device comprises the pyrotechnic device component as claimed in claim 9.

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