KR101437609B1 - Micro-Mesoporous Melamine Resin as a Nanocomposite Support for Nano High Energy Materials, and Manufacturing Method thereof - Google Patents

Abstract

The present invention relates to a process for producing a mixture of a melamine monomer, a terephthalaldehyde and a mesoporous hexagonal plate type silica mold with a solvent to obtain a mixed solution; A second step of heating the mixed solution to polymerize to obtain a polymer; A third step of obtaining a solid phase mixture containing the polymer; And a fourth step of removing the mesoporous hexagonal plate-shaped silica template from the solid mixture. The present invention also relates to a method for producing a mesoporous melamine resin for a high energy material carrier.

Description

TECHNICAL FIELD The present invention relates to a mesoporous melamine resin for use in a high energy material carrier,

The present invention relates to materials that increase the thermal stability and adsorption of high energy materials. More specifically, the present invention relates to a method for producing a mesoporous melamine resin comprising a step of polymerizing a melamine monomer to increase the thermal stability and adsorption amount of a high energy material, a mesoporous melamine resin prepared using the same, To a method for encapsulating a high energy material.

Materials such as RDX (Cyclotrimethylenetrinitramine), HMX (High-Molecular-weight RDX, Octogen) and TNT (Trinitrotoluene) have been classified as explosive chemicals and are now widely used as explosives. At the time of World War II, RDX was used as a trigger for explosives, causing pollution of soil and water quality, which has become a global problem. Research on the detection and adsorption of explosive chemicals has been conducted accordingly.

In this regard, a detection method using HPLC, a detection method using RAMAN, and a detection method using ionization mass spectrometry can be used. These methods lower the detection limit of explosives remaining in water or soil and focus on selective detection of explosives.

On the other hand, RDX is susceptible to static electricity and impact, which easily explodes, making it difficult to handle explosives.

Thus, there has been an attempt to create and desensitize nano RDX particles using an atomizer. However, it is disadvantageous that the nozzles used in the atomizer have difficulty in miniaturization and the actually measured diameter of the RDX has a micron size and forms a part of the RDX of the nano size.

Lev N. Krasnoperov and colleagues have succeeded in nanoizing RDX by using supercritical CO ₂ as a solvent as a kind of RESS (Rapid expansion of supercritical solutions). The RDX nanotization method using carbon dioxide as a material of RESS (Rapid expansion of supercritical solutions) dissolves RDX in supercritical carbon dioxide and induces the separation of RDX crystals by using the expansion due to CO ₂ state change, Wherein the average particle size of the RDX produced is 100 nm, but it has various sizes ranging from 100 nm to 300 nm, and the use of supercritical carbon dioxide has a disadvantage of consuming a large amount of energy. [Phys. Chem. Chem. Phys., 2007, 9, 5249.5259]

In order to solve these drawbacks, there has been a need for a support for lowering the sensitivity of explosives, and studies are underway. Carriers maintain the explosive nature of the explosive itself, which is the ideal role of porcelain, and play a role of insensitivity to explosives only when embedded in the carrier.

As a result of such studies, Victor Stepanov and colleagues have found that the size of the crystals has the greatest impact on the sensitivity of explosives (Propellants Explos. Pyrotech. 2011, 36, 240-246).

Yongjun Ma and colleagues have also used RDX as a surfactant, such as sodium dodecyl benzene sulfonate (SDBS) and p-octyl polyethylene glycol phenylether (OP) (BC), which has a porous structure. As a result, the maximum amount of the RDX which did not explode was 87.47 wt% based on the mass of porcelain (Journal of Energetic materials, 2011, 29, 150-161).

In addition, M. Smeu and colleagues have verified that RDX can be stabilized by the confinement effect when RDX is placed inside carbon nanotubes using DFT calculations (Journal of Physical Chemistry C. 2011, 115 , 10985-10989).

In addition, studies have been conducted to maintain the explosive power as well as the stability when supporting the explosive on the support. Denis Spitzer and colleagues carried RDX onto porous Cr ₂ O ₃ by the impregnation method. The lower the amount of RDX compared to the carrier, the similar to the physical properties of pure RDX, but the closer to 95%, the more stable the impact sensitivity and the friction sensitivity. Physics and Chemistry of Solids 2010, 71, 100-108)

Using a mesoporous carbon material composed of carbon among the mesoporous materials widely known to have a trapping effect, a researcher of the present invention has shown the adsorption amount and thermal insensitivity of TG by carrying RDX on a mesoporous carbon body.

However, the mesoporous carbon body undergoes a carbonization process to have a graphitic structure, and this somewhat non-fluid structure interferes with adsorption of RDX into the pores.

J.P. Agrawal and his colleagues used polymeric binders such as polyester, polyurethane, nylon, polystyrene and epoxy resin to overcome the disadvantages of explosive RDX, high explosiveness, sensitivity, unevenness and temperature resistance. In particular, RDX was made more stable by using epoxy resin (Journal of Energetic Materials, 19: 2-3, 255-272).

In order to facilitate the entry of high-energy materials such as RDX into the pores, the present inventors have developed a hexagonal plate-type silica (INC-2) of a patent (patent registration No. 10-1080681) And melamine resins with mesopores were synthesized by applying mesopores to melamine resins with low cost and applied to RDX encapsulation.

Korean Patent No. 10-1080681B

It is an object of the present invention to provide a method for producing a mesoporous melamine resin for a high energy material carrier, in order to adsorb high energy material and impart insensitivity.

It is another object of the present invention to provide a mesoporous melamine resin for a high energy material carrier for adsorbing a high energy material and imparting insensitivity thereto.

It is also an object of the present invention to provide a method of encapsulating a high energy material for thermal stability and dulling of a high energy material.

In order to achieve the above object,

Mixing melamine monomer, terephthalaldehyde and mesoporous hexagonal plate type silica mold with a solvent to obtain a mixed solution;

Heating the mixed solution to polymerize to obtain a polymer;

Obtaining a solid mixture containing said polymer; And

And removing the mesoporous hexagonal flaky silica mold from the solid mixture. The present invention also provides a method for producing a mesoporous melamine resin.

The present invention also relates to a process for preparing a solid mixture comprising mixing a melamine monomer, a terephthalaldehyde and a mesoporous hexagonal plate type silica mold with a solvent to obtain a mixed solution, heating the mixture to effect a polymer reaction, A mesoporous melamine resin for a high energy material carrier obtained by removing the mesoporous hexagonal plate type silica mold from a solid mixture is provided.

The present invention also provides a method of encapsulating a high energy material comprising the step of encapsulating a mesophase melamine resin prepared according to the present invention by adding a high energy material together with a solvent.

The mesoporous melamine resin prepared according to the present invention increases the surface area by the mesopores generated by the template material. Therefore, when applied as a support material of a high energy material, it is effective for encapsulating a high energy material, It is possible to secure stability and to effectively use it for transportation and storage of high energy materials.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a schematic representation of a mesoporous melamine resin according to one embodiment of the present invention.
2 is a nitrogen adsorption and desorption curve of the mesoporous melamine resin according to one embodiment of the present application.
FIG. 3 is a graph showing the inclusion amount and insensitivity of RDX when a mesoporous melamine resin synthesized according to one embodiment of the present invention is used.
FIG. 4 is a TGA analysis result when RDX is embedded in the mesoporous melamine resin synthesized according to one embodiment of the present invention. FIG.
FIG. 5 illustrates the case where the RDX is encapsulated in the mesoporous melamine resin synthesized according to one embodiment of the present application. It is a bar graph showing the adsorption efficiency to the input ratio of RDX.
FIG. 6 shows the result of PSD (Pore Size Distribution) analysis by BET isotherms.

Hereinafter, the present invention will be described in detail.

The present invention

Mixing a melamine monomer, terephthalaldehyde and mesoporous hexagonal plate type silica mold with a solvent to obtain a mixed solution;

A second step of heating the mixed solution to polymerize to obtain a polymer;

A third step of obtaining a solid phase mixture containing the polymer; And

And a fourth step of removing the mesoporous hexagonal plate-shaped silica template from the solid mixture. The present invention also provides a method for producing a mesoporous melamine resin for a high energy material carrier.

Mesoporous materials are important materials with various applications such as adsorbents, ion exchange materials, and catalysts. According to IUPAC definition, the microporous means that the pore size is 2 nm or less, the mesoporous has the pore size of 2 to 50 nm, and the macroporous has the pore size of 50 nm or more.

The first step is a step of mixing a melamine monomer, terephthalaldehyde and mesoporous hexagonal plate type silica mold with a solvent to obtain a mixed solution. Synthesis of Mesoporous Melamine Resin Referring to FIG. 1, Melamine and terephthalaldehyde, which are the skeletons of the resin, form a melamine resin in a mesoporous hexagonal plate type silica mold.

Unlike the conventional graphite structure due to the carbonization process of the mesoporous carbon material, the melamine monomer prevents the adsorption of the high energy material into the pores, when the mesopores are formed, Thus facilitating the entry of high energy material into the pores without causing such problems.

In the present invention, mesoporous hexagonal plate type silica is used as a template as a mold for the production of a mesoporous melamine resin.

As the mesoporous hexagonal plate type silica, those disclosed in Korean Patent No. 10-1080681 are preferably used, but not always limited thereto. In the present application, the mesoporous hexagonal plate type silica disclosed by the above document is referred to as "INC-2 ".

According to the above document, INC-2 was prepared by irradiating an aqueous solution containing an inorganic silica precursor, aminopropyltriethoxysilane (APTES) and a P123 surfactant in an acidic condition, and then extracting a surfactant template And the hexagonal small-plate type silica obtained by removing the hexagonal small-plate type silica.

The solvent of the first step may be at least one solvent selected from the group consisting of dimethylsulfoxide (DMSO), N-methylpyrrolidone (NMP), dimethylacetamide (DMAc) and dimethylformamide Soluble organic solvent.

It is preferable that the mixed solution contains 7-40 wt% of melamine monomer, 5-25 wt% of terephthalaldehyde, 10-40 wt% of mesoporous hexagonal plate type silica, and a residual solvent. At this time, it is preferable that the ratio of melamine monomer / terephthalaldehyde in the mixed solution is maintained at 0.3 to 2.0.

The second step is a step of heating the mixed solution to obtain a polymer by a polymer reaction. At this time, the air is removed by using an inert gas such as argon, and the mixture is aged at 120 to 180 ° C for 24 to 120 hours using a reflux apparatus, and then cooled to room temperature to obtain a precipitated white solid.

The third step is a step of obtaining a solid-phase mixture containing the polymer.

For this purpose, the precipitated polymer is filtered using a screening apparatus such as a Buchner funnel and washed with an excess of acetone, tetrahydrofuran, dichloromethane or the like.

The resulting solid phase mixture is a mesoporous hexagonal plate type silica containing a melamine resin.

In the fourth step, mesoporous hexagonal plate type silica molds are removed from the solid phase mixture using hydrofluoric acid, ammonium fluoride, or the like.

As a result, a solid mixture in which the mesoporous hexagonal plate type silica is removed can be obtained.

Analysis of this solid mixture by PSD (Pore Size Distribution) by BET isotherms revealed it to be a melamine resin with mesopores.

FIG. 6 is a graph showing the pore distribution in the nitrogen adsorption-desorption curve of the melamine resin. The maximum peak of the pore size was confirmed at 3.85 nm, indicating that the melamine resin had mesopores.

Another aspect of the present invention is to provide a method for producing a solid mixture comprising mixing a melamine monomer, a terephthalaldehyde and a mesoporous hexagonal plate type silica mold with a solvent to obtain a mixed solution, heating the mixed solution to effect a polymer reaction, And a mesoporous melamine resin for a high energy material carrier obtained by removing the mesoporous hexagonal plate type silica mold from the solid mixture.

The present invention also provides a method of embedding a high energy material in a mesoporous melamine resin prepared according to the present invention.

More specifically, the present invention provides a method for encapsulating a high energy material comprising the step of encapsulating a mesophase melamine resin prepared according to the present invention by adding a high energy material together with a solvent.

The high energy material may be RDX (Cyclotrimethylenetrinitramine), HMX (High-Molecular-weight RDX, Octogen), TNT (Trinitrotoluene) and the like, preferably RDX.

The solvent may be acetone, dimethylformamide (DMF), dimethylsulfoxide (DMSO), ethanol, or the like, but is not limited thereto.

In one embodiment of the present invention, when the high energy material is RDX and acetone is used as the solvent, the ratio of RDX to acetone is preferably 1 mM to 1 M. At this time, the total amount of acetone is always fixed to 50 ml when 0.5 g of melamine resin is used.

The atmospheric pressure is preferably 0.1 to 1 atm and the temperature is preferably 25 to 60 ° C.

It is preferable that the temperature is kept constant when the solvent is evaporated.

TG-DTA analysis can be performed to confirm whether the mesoporous melamine resin prepared according to the present invention has RDX coverage and insensitivity.

Hereinafter, the present invention will be described more specifically with reference to preferred embodiments. In the following description, descriptions of techniques and the like well known in the art are omitted. However, those skilled in the art will readily understand the characteristic features and effects of the present invention through the following embodiments, and can implement the present invention without any difficulty.

< Synthetic example  1>: Mesoporous  Synthesis of melamine resin

A mixed solution was prepared by mixing 313 mg of melamine, 500 mg of terephthalaldehyde, 1 g of mesoporous hexagonal plate type silica (INC-2) and 15.5 ml of dimethyl sulfoxide After that, air was removed using argon. Then, the mixed solution was aged at 180 ° C for 72 hours using a reflux device, and then cooled to room temperature. The precipitated white solid was filtered using a screener (Buchner funnel) and washed with excess acetone, tetrahydrofuran, dichloromethane to give a solid mixture. This was immersed in 200 ml of a 5% HF solution for 12 hours to dissolve the mesoporous hexagonal plate type silica (INC-2) as a template. Then, the solution was filtered using a pressure-reducing device, washed with a large amount of water, and dried at 100 ° C. to obtain a mesoporous melamine resin.

< Example  1>: RDX Enclosure

2.0 mmol of RDX was dissolved in 50 ml of acetone and 0.1 g of the mesoporous melamine resin synthesized in Synthesis Example 1 was mixed. Then, acetone was naturally dried at room temperature for 1 day.

<Evaluation of TG-DTA>

RDX and mesoporous melamine resin dried according to Example 1 were analyzed by TG-DTA method to confirm the amount of actually supported RDX and the thermal stability of the enclosed RDX. At this time, the TG-DTA method was carried out at a rate of 10 ° C per minute to 100 ° C, maintained at 100 ° C for 30 minutes and then measured at 250 ° C at a rate of 2 ° C per minute.

2 is a graph showing nitrogen adsorption / desorption lines when RDX is encapsulated in the meso-processed melamine resin synthesized by Synthesis Example 1 according to Example 1. Fig.

The difference in adsorption and desorption lines between the X-axis relative pressure values of 0.4 and 1.0 indicates a hysteresis loop, which is evidence of mesopores. It can be seen that the absolute value of adsorption and desorption curves decreases as the amount of RDX added increases.

In addition, the adsorption amount of N ₂ before the initial RDX adsorption is 150 cm ³ / g, whereas the adsorption amount at 25% or more shows an adsorption amount of N _{2 of} less than 25 cm ³ / g. This means that the RDX is adsorbed in the pores and the area and volume of adsorbed N ₂ by mesopores is reduced. In addition, the adsorption curves do not decrease in proportion to the initial RDX doses of 25%, 50%, 75% and 100%. This means that at 25% or more, RDX blocks the inlet of the pores and prevents the nitrogen from penetrating into the pores, thereby measuring the pore volume smaller than the actual remaining pore volume.

3 shows a curve measured by the TG-DTA method in which RDX was embedded in the mesoporous melamine resin synthesized by Synthesis Example 1 according to Example 1. Fig. The amount of RDX supported can be determined from the reduced amount from 100%, and the insensitivity of the loaded RDX can be determined from the Tp point of the DTA curve. Where Tp represents the value of the highest vertex of the DTA curve.

&Lt; Evaluation of adsorption efficiency >

FIG. 5 is a bar graph showing the adsorption efficiency with respect to the input ratio of RDX by incorporating RDX according to Example 1 into the mesoporous melamine resin synthesized by Synthesis Example 1. FIG. The input ratio of RDX means the volume ratio of the input RDX to the initial pore volume of the mesoporous melamine resin. In addition, the adsorption efficiency is the value obtained by dividing the amount of RDX actually adsorbed in the mesoporous melamine resin by the initial amount of RDX, and is used as an index showing the relationship between the mesopores and the RDX in the melamine resin. As shown in FIG. 5, the adsorption efficiency increases with an increase in the input ratio of RDX because the attraction between the pores in the mesoporous melamine resin and the RDX increases as the adsorbed RDX increases, and the adsorption efficiency increases .

<BET evaluation>

Table 1 below shows the surface area and pore volume of the mesoporous melamine resin synthesized according to Synthesis Example 1 according to the results of the BET measurement of the RDX according to Example 1.

RDX input (based on initial pore volume) Pore surface area (m 2 / g) Pore volume (cm 3 / g) 0% 451 0.70 25% 75 0.37 50% 61 0.29 75% 49 0.26 100% 42 0.22

In Table 1, the amount of RDX was expressed as a ratio of the RDX volume adsorbed to the pores with respect to the initial pore volume of the melamine resin. For example, in Table 1 above, 25% means X (volume of adsorbed RDX) /0.70 (initial pore volume) x 100% = 25%.

As shown in Table 1, the pore surface area of the mesoporous melamine resin before RDX adsorption was 451 m ² / g, but the pore surface area was 75 m ² / g when the RDX input amount was 25%, 61 m ² / g when the RDX adsorption amount was 50% It decreases to 49m ² / g at 75% and to 42m ² / g at 100%. The initial pelletization rate of the mesoporous melamine resin before RDX adsorption was 0.7 cm ³ / g, but when the RDX input amount was 25%, the pore volume was 0.37 cm ³ / g, when it was 50%, 0.29 cm ³ / g, when it can be confirmed that reduced to ^{0.26cm 3 / g, 0.22cm 3 /} g at 100%. As shown in FIG. 2, the proportion of the pore volume is not reduced in proportion to the amount of RDX, because the RDX blocks the inlet of the pores and interferes with the adsorption of N ₂ , so that the pore volume is measured to be smaller than the actual pore volume.

&Lt; Evaluation of the amount of RDX, adsorption efficiency and Tp in the bag body >

Table 2 shows the amount of RDX present in the corpuscles analyzed by using TG-DTA equipment and the adsorption efficiency of RDX according to Example 1 to the mesoporous melamine resin synthesized by Synthesis Example 1, , And Tp (the maximum vertex of the DTA curve by RDX). Here, Tp denotes the highest point of the normal distribution curve, Tf denotes the end point of the normal distribution curve, and Ti denotes the starting point of the normal distribution curve.

RDX doses
(Based on initial pore volume) RDX content Adsorption efficiency T _p ( ^o C) 25% 18.54% 74.14% 195.13 50% 48.61% 97.22% 196.79 75% 71.36% 95.15% 200.44 100% 99.40% 99.40% 205.17

In Table 2, the RDX dosing amount is as described in the above description of Table 1, and the adsorption efficiency is as described in the description of FIG.

Tp depends on the workforce of RDX and mesoporous melamine resins. The value of Tp should decrease for RDX nanoparticles in pores. In Table 2, it can be seen that the Tp value decreases as the RDX input amount decreases. This means that due to the nanoization of RDX in the pores, the Tp value is lower than the decomposition temperature of the existing RDX. RDX is nanoized by diffusing into pores, which causes each nano RDX to fall off by pores, resulting in a lower decomposition temperature.

4 is a graph showing the relationship between the amount of RDX encapsulated by the TGA method (black line, 1) and the Tp value corresponding to each of the mesoporous melamine resin synthesized in Synthesis Example 1 and RDX according to Example 1 (Blue line, 2). It can be seen that the Tp value increases as the amount of embedded RDX increases. It can be confirmed that the Tp value is 205 ° C when the RDX of 100% level is applied to the pore volume of the mesoporous melamine resin. Since the decomposition temperature of pure RDX is 205 ° C, it can be seen that as the amount of adsorbed RDX increases, the nature of the contained RDX becomes the same as that of pure RDX.

<RDX impact stability evaluation>

Table 3 below shows the results of the experiment on the impact stability of RDX existing in the corpuscle using the impact stability tester by covering RDX according to Example 1 to the mesoporous melamine resin synthesized by Synthesis Example 1 above. Determine whether the RDX is exploded by the energy generated by dropping the weight on the melamine resin encapsulated in the RDX.

RDX content in melamine resin
(Wt%) (w / w) Weights energy
(J) Drop height
(Cm) Drop Weight
(kg) 100 48.5 5 23.8 200 35.8 2 17.5 300 67.9 2 13.3

The weights and dropping heights of the weights shown in Table 3 indicate the minimum conditions under which the RDX would explode, and the energy at that time was calculated. The energy required to explode by the impact of a typical RDX crystal is 7.5J. However, the energy shown in Table 3 is 13.3J ~ 23.8J, which is higher than 7.5J. This means that more energy must be exerted to explode, indicating that the RDX encapsulated in the melamine resin is desensitized.

The present invention can be variously modified and modified within the scope of the following claims, all of which are within the scope of the present invention. Accordingly, the invention is limited only by the claims and the equivalents thereof.

Claims (16)

Mixing a melamine monomer, terephthalaldehyde and mesoporous hexagonal plate type silica mold with a solvent to obtain a mixed solution;
A second step of heating the mixed solution to polymerize to obtain a polymer;
A third step of obtaining a solid phase mixture containing the polymer; And
And a fourth step of removing the mesoporous hexagonal plate-shaped silica mold from the solid mixture, wherein the mesoporous melamine resin for mesoporous melamine resin for high energy material carrier comprises:
Wherein the second step includes a step of removing air using an inert gas and then aging the mixture at 120 to 180 ° C for 24 to 120 hours using a reflux apparatus, A method for producing a melamine resin. The method according to claim 1, wherein the high energy material is RDX (Cyclotrimethylenetrinitramine), HMX (High-Molecular-weight RDX, Octogen) or TNT (Trinitrotoluene). The method of claim 1, wherein the solvent is at least one water-soluble organic solvent selected from the group consisting of dimethylsulfoxide (DMSO), N-methylpyrrolidone (NMP), dimethylacetamide (DMAc), and dimethylformamide Wherein the melamine resin is a melamine resin. [3] The method according to claim 1, wherein the mixed solution comprises 7 to 40% by weight of a melamine monomer, 5 to 25% by weight of terephthalaldehyde, 10 to 40% by weight of a mesoporous hexagonal plate type silica, (METHOD FOR MANUFACTURING MESHAMINE MELAMINE RESIN FOR ENERGY SUBSTANCE. The method for producing a mesoporous melamine resin according to claim 1, wherein the weight ratio of melamine monomer / terephthalaldehyde in the mixed liquid is 0.3 to 2.0. delete delete [3] The method of claim 1, wherein the third step is a step of washing the polymer by using a sieving device and washing the polymer with acetone, tetrahydrofuran, or dichloromethane, A method for producing a melamine resin. [4] The method of claim 1, wherein the fourth step comprises removing the mesoporous hexagonal plate type silica mold from the solid mixture using hydrofluoric acid or ammonium fluoride Wherein the method comprises the steps of: preparing a mesoporous melamine resin; A mesoporous melamine resin for a high energy material carrier prepared according to claim 1. The mesoporous melamine resin for a high energy material carrier according to claim 10, wherein the high energy material is RDX (Cyclotrimethylenetrinitramine), HMX (High-Molecular-weight RDX, Octogen) or TNT (Trinitrotoluene). 10. A method of encapsulating a high energy material comprising the step of embedding a high energy material together with a solvent in the mesoporous melamine resin of claim 10. The method of claim 12, wherein the solvent is acetone. 13. The method of claim 12, wherein the high energy material is cyclotrimethylenetrinitramine (RDX), high-molecular-weight RDX, octogen (HMX), or trinitrotoluene (TNT). 13. The method of claim 12, wherein the high energy material is RDX and the solvent is acetone and the ratio of RDX to acetone is 1 mM to 1 M. The method of claim 12, wherein in the inclusion step, the atmospheric pressure is 0.1 to 1 atm and the temperature is 25 to 60 ^° C.

Images