RU2309139C2 - Initiating explosive composition - Google Patents

Abstract

FIELD: explosive substances.

SUBSTANCE: invention relates to initiating explosive substances showing sensitivity to impulse laser radiation of low power. Invention proposes initiating explosive composition showing sensitivity to low-temperature laser radiation and containing 5-hydrazinotetrasol mercury (II) perchlorate, polymethylvinyltetrazole and nanodiamonds used for detonation synthesis. Invention provides reducing threshold of initiating the explosive composition, retaining high adhesion to surface of explosive substance and safety in handling. Invention can be used in agents used for initiating as a generator of flat, cylindrical, spherical and complex forms of impact waves, and in optical systems for initiating explosive charges.

EFFECT: improved and valuable properties of composition.

1 tbl, 1 ex

Description

Technical field

The invention relates to initiating explosives excited by low-power pulsed laser radiation and can be used in initiating means as a generator of flat, cylindrical, spherical and complex shape of shock waves, as well as in optical systems for initiating explosive charges.

State of the art

Laser initiation is a relatively new method of detonating explosives (BB), characterized by increased safety. Laser initiation provides a high level of isolation of the detonator from the spurious pulse, since there are no random sources in the optical range with a power sufficient to detonate the detonator [Ilyushin MA, Tselinsky IV Initiating explosives. Ross Chem. Zhurn. - 1997, t. 41, No. 4, p. 3-13].

Photosensitive explosives are used in fiber optic detonator capsules operating under the influence of pulsed laser radiation.

Laser initiation can be successfully used in many explosive technologies that require an individual approach to the development of detonation systems:

- explosive welding, stamping, hardening, compaction, synthesis of new materials can be carried out with the fiber optic initiation of one or more light detonators by undermining the film charges of the photosensitive explosives by the direct beam of a pulsed laser;

- mining and blasting operations, both overburden and in mines hazardous for gases and dust, require the simultaneous or short-delayed initiation of a large number of light detonators through fiber optic communication lines;

- automated technologies with a pulsed-periodic supply of material on which a film charge of a photosensitive explosive is applied or an explosive charge initiated from a light detonator is placed can be carried out by transmitting a laser pulse directly through air or in vacuum;

- single-use explosive technology, used, for example, in the pyro-automation of spacecraft, needs dozens of fiber-optic channels that simultaneously transmit a signal to light detonators from an onboard pulsed laser of limited power;

- when perforating deep wells, heat-resistant fiber-optic detonators with a high sensitivity to a laser pulse should be used, ensuring reliable initiation of up to 100 cumulative charges of blasting explosives;

- with low-hazard technology for producing nanodiamonds of detonation synthesis;

- when conducting blasting operations in conditions of a high level of electromagnetic interference, special shielded fiber optic detonators are required.

One of the main elements of the laser initiation chain are photosensitive energy-intensive substances. Depending on the solution of specific problems, inorganic azides and energy-consuming metal complexes with different values of the initiation thresholds by a laser single pulse (pulse time of 10 ^-8 s) or a single pulse (pulse time of up to ~ 10 ^-3 s) were proposed as photosensitive explosives for light detonators.

And one of the most effective initiating explosives (IVS) is perchlorate 5-hydrazinotetrazolruti (II), which is used individually and in the form of mixtures with optically transparent polymers in optical initiation systems as a highly photosensitive energy-intensive substance with a low threshold for sensitivity to pulsed laser radiation in the visible and near infrared spectral regions (wavelength 1.06 μm) [Chernay A.V., Zhitnik N.E., Ilyushin M.A., Sobolev V.V., Fomichev V.V. Patent of Ukraine No. 17521Ayu 1997; Ilyushin M.A., Tselinsky I.V. Energy-intensive matellokompleksy in the means of initiation // Ross. Chem. Zhurn. - 2001. No. 1, pp. 72-78].

5-Hydrazinotetrazolruti (II) perchlorate [Hg (CH ₄ N ₆ )] (ClO ₄ ) ₂ has the following characteristics: molecular weight 499.577; the density of single crystals ~ 3.45 g / cm ³ ; flash point (5 second delay) about 186 ° C; thermal decomposition activation energy ~ 90.2 kJ / mol; sensitivity to shock (Koeler Weler) (lower limit / upper limit) 60/125 mm; sensitivity to a fire beam of a fire-resistant cord (100% response / 100% failure) 60/150 mm; detonation velocity at a density of 3.4 g / cm ³ ~ 6 km / s (calculation); the minimum charge for RDX in detonator capsule No. 8 is ~ 0.015 g. Perchlorate 5-hydrazinotetrazolruti (II) is non-hygroscopic, insoluble in water, alcohol, acetone, aliphatic, chlorinated and aromatic hydrocarbons, soluble in dimethyl sulfoxide, oxidized with an alkaline solution of KMnO ₄ does not dissolve . The introduction of 5-hydrazinotetrazolruti (II) polymers into perchlorate dramatically reduces the sensitivity of the compositions to mechanical stresses, which makes them relatively safe during transportation, storage and use [Scientific and technical report on research work “Light-sensitive materials for light products used in downhole equipment” / hands. Tselinsky I.V., St. Petersburg. SPbGTI (TU), 2002. p.14; Ilyushin M.A., Tselinsky I.V., Chernay A.V. Photosensitive explosives and compositions and their initiation by a laser monopulse.// Ross. Chem. Zhurn. - 1997, No. 4, p.81-88].

Perchlorate 5-hydrazinotetrazolruti (II) has the gross formula CH ₄ N ₆ O ₈ Cl ₂ Hg and the structural formula

The closest analogue is the use of 5-hydrazinotetrazolruti (II) perchlorate in a photosensitive composition containing ~ 90% of this compound and ~ 10% of an optically transparent polymer (composition BC-2) [RF Patent Application 2002113197/15. The method of producing perchlorate 5-hydrazinotetrazolruti (II) from 05.20.2002, Ilyushin M.A., Tselinsky I.V. The decision to grant a patent dated September 26, 2003].

The disadvantage of the prototype is that the minimum initiation energy (E _cr ) of this composition is a sufficiently large value of 310 μJ.

The objective of the present invention is to obtain a technical result, which is expressed in lowering the threshold of initiation of the composition with perchlorate 5-hydrazinotetrazolruti (II) with a monopulse of a neodymium laser (wavelength 1.06 μm).

Disclosure of invention

The basis of this invention is the task to create such a composite material that would significantly reduce the initiation threshold while maintaining all the other positive characteristics of the composition (high adhesion to the explosive surface, high handling safety of the composition, convenience and ease of application, the same time delay initiation and etc.).

The solution to the problem lies in the fact that the proposed initiating composition containing perchlorate 5-hydrazinotetrazolruti (II) and a polymer - polymethylvinitetrazole, which according to the invention further includes detonation synthesis nanodiamonds in the following ratio of components, wt.%:

5-hydrazinotetrazolruti (II) perchlorate - 85.7-90.0;

polymer - polymethylvinitetrazole - 9.5-10.0;

detonation synthesis nanodiamonds - 0.1-5.0.

The best embodiment of the invention

The proposed composition containing nanodiamonds in an amount of 0.1-5.0 wt.% Of the total weight of the composition, provides a simultaneous increase in sensitivity to the action of a laser pulse by 1.5-1.7 times and high adhesion to the contact surface due to increased adhesion properties thermoplastic (polymethylvinyltetrazole).

Cluster nanodiamonds used in this method are particles that are close in shape to spherical or oval, without sharp edges (non-abrasive). Such diamonds form sedimentation and coagulation stable systems in various types of liquid media.

Currently, UDD synthesis is carried out by undermining specially prepared charges from TNT-hexogen mixed compositions in explosive chambers filled with a non-oxidizing medium [V.Yu. Dolmatov. Ultrafine detonation synthesis diamonds. St. Petersburg, Publishing House SPbSPI, 2003, 344 p.]. The resulting diamond charge (a mixture of diamonds with non-diamond forms of carbon) is subjected to chemical cleaning, the most advanced of which is the processing of the diamond charge in nitric acid at high temperatures and pressure, followed by washing [Russian Patent No. 2109683, cl. СВВ 31/06, publ. 03/05/96, the Method of separation of synthetic ultrafine diamonds. V.YU.Dolmatov, V.G.Sushchev, V.A. Marchukov].

From the point of view of morphology, UDDs are a powder with a specific surface area of 150-450 m ² / g and a pore volume of 0.3-1.5 cm ³ / g (in the dry state). In suspension, UDD aggregates can have a size of up to 50 nm (0.05 μm), subject to special treatment. The average size of individual diamond crystals is 4-6 nm (0.004-0.006 microns) [Dolmatov V.Yu. Experience and prospects of non-traditional use of ultrafine diamonds of explosive synthesis. Superhard materials, 1998, No. 4, pp. 77-81].

UDDs have a classical cubic (diamond) crystal lattice with large surface defects, which leads to a significant surface energy of such crystals. The excess surface energy of UDD particles is compensated by the formation of numerous surface groups, forming a shell ("fringe") on the surface of hydroxyl, carbonyl, carboxyl, nitrile, quinoid, and other groups chemically bonded to the crystal, representing various stable combinations of carbon with other elements of explosives used substances - oxygen, nitrogen and hydrogen [Dolmatov V.Yu. and others, ZHPH, 1993, t.66, No. 8, p.1882]. UDD microcrystallites cannot exist without such a shell under ordinary conditions - this is an integral part of cluster nanodiamonds, which largely determines their properties.

Thus, UDD combines a paradoxical beginning - a combination of one of the most inert and solid substances in nature - diamond (core) with a sufficiently chemically active shell in the form of various functional groups that can participate in various chemical reactions. In addition, such diamond crystals, despite the compensation of part of unpaired electrons due to the formation of surface functional groups, still have a rather large excess of them on the surface, i.e. each diamond crystal is, in essence, a multiple radical.

As a percentage, the proportion of non-diamond carbon in high-quality UDD varies from 0.4 to 1.5 by weight of the substance. It is significant that the so-called non-diamond carbon in this case does not constitute a separate phase or individual particles and is not defined crystallographically as graphite or micrographite. Two forms of carbon — diamond and non-diamond — differentiate according to the electronic state of atoms and chemical reactivity with respect to liquid-phase oxidizing agents [Dolmatov V.Yu., Gubarevich TM ZhPKh, 1992, t.65, No. 11, p.2512]. The task of peripheral non-diamond structures is to ensure the maximum effect of a particle with a matrix material - with polymethylvinyltetrazole at the time of its polymerization in the form of a film on the contact surface. Diamond tetrahedral sp ³ -carbon is chemically and sorption inactive, non-diamond electronic carbon configurations (sp ² and sp) are much more labile and, together with oxygen and hydrogen heteroatoms, form an adsorption-active “coat” on top of the diamond core, which is sufficiently stable with the polymerisable polymer chemical bonds.

The introduction of nanodiamonds into the polymer in an amount of 0.1-5.0% contributes to a significant increase in the cohesive (1.5-3.0 times) and adhesive properties (1.7-2.5 times) vulcanized polymer, which occurs in in case of using polymethylvinyltetrazole. A film with nanodiamonds has a very high resistance to thermal aging, can be stored unchanged for at least three years. Such a film is characterized by an increase in elastic-strength properties, which can significantly increase the range of its use.

It is known that finely dispersed soot has been successfully applied in some cases to increase the susceptibility of energy materials to a single pulse of infrared lasers [Koma M., Vormisto T., Minkio M., Sairiala M. Laser ignition research of RDX, Seminar. Levi. Finland Sept. 5-11, 2002, p. 266-271, Chem. Abstr., 2003, vol. 138. ref.403740]. However, the effect of other allotropic forms of carbon on the thresholds of laser initiation of energy materials has not been studied.

For comparison, the table shows the effect of ultrafine soot (particle size ~ 1 μm) and nanodiamonds on the initiation threshold of the photosensitive composition BC-2. The initiation of explosive compositions was carried out under the influence of a single pulse of a neodymium laser (wavelength 1.06 μm, pulse time τ _q = 30 ns, aperture diameter 0.86 mm, total pulse energy E = 1.5 J). The studied samples were copper caps with a diameter of 5 mm and a height of 2 mm, filled with the composition of the BC-2.

Table No.
p / p The composition of the sample, wt.% Min. initiation energy, E _cr , μJ Initiation result one The composition of the BC-2:
(Perchlorate 5-hydrazinotetrazolruti (II) - 90
Polymer - polymethylvinyltetrazole - 10) 310 detonation 2 Perchlorate 5-hydrazinotetrazolruti (II) - 89.10
Polymer - polymethylvinyltetrazole - 9.90
Soot - 1 2000 detonation 3 Perchlorate 5-hydrazinotetrazolruti (II) - 89.9
Polymer - Polymethylvinyltetrazole - 10.0
Nanodiamonds - 0.1 300 detonation four Perchlorate 5-hydrazinotetrazolruti (II) - 89.6
Polymer - Polymethylvinyltetrazole - 9.9
Nanodiamonds - 0.5 260 detonation 5 Perchlorate 5-hydrazinotetrazolruti (II) - 89.10
Polymer - Polymethylvinyltetrazole - 9.9
Nanodiamonds - 1.0 200 detonation 6 Perchlorate 5-hydrazinotetrazolruti (II) - 88.2
Polymer - polymethylvinyltetrazole - 9.8
Nanodiamonds - 2.0 180 detonation 7 Perchlorate 5-hydrazinotetrazolruti (II) - 87.4
Polymer - Polymethylvinyltetrazole - 9.7 Nanodiamonds - 2.9 190 detonation 8 Perchlorate 5-hydrazinotetrazolruti (II) - 86.5
Polymer - Polymethylvinyltetrazole - 9.6 Nanodiamonds - 3.9 240 detonation 9 Perchlorate 5-hydrazinotetrazolruti (II) - 86.1
Polymer - Polymethylvinyltetrazole - 9.6 Nanodiamonds - 4.3 285 detonation 10 Perchlorate 5-hydrazinotetrazolruti (II) - 85.7
Polymer - Polymethylvinyltetrazole - 9.5 Nanodiamonds - 4.8 300 detonation eleven Perchlorate 5-hydrazinotetrazolruti (II) - 85.4
Polymer - Polymethylvinyltetrazole - 9.6 Nanodiamonds - 5.0 310 detonation

The data in the table allow us to conclude that finely dispersed soot significantly increases the initiation threshold of the BC-2 composition by a single laser pulse. This result can be explained by the dissipation of the laser energy absorbed by the finely dispersed soot from the surface of the sample of the BC-2 composition, which leads to a deterioration in the conditions for the formation of the initiation zone inside the composition layer with an increase in the critical ignition energy.

The action of nanodiamonds on the composition of the BC-2 is different from the effect on it of ultrafine soot. The introduction of nanodiamonds up to 5.0% wt. lowers the initiation threshold of the BC-2 composition by a single pulse of a neodymium laser. This effect can be explained as a result of an increase in volumetric illumination inside the charge and an improvement in the conditions for the formation of the initiation focus due to the introduction of nanodiamonds with a significantly higher refractive index than the initial composition. A further increase in the number of nanodiamonds in the composition leads to a decrease in its susceptibility to laser radiation. The increase in the initiation threshold of the BC-2 composition, containing more than 5 wt.% Nanodiamonds, is obviously a consequence of the negative effect of dilution of the photosensitive composition with an inert additive.

The delay time for the initiation of the composition of the BC-2 with the introduction of nanodiamonds up to 5% wt. does not change and is 11-12 μs.

For a better understanding of the present invention provides specific examples of its implementation.

Example 1

To 90 mg of 5-hydrazinotetrazolruti (II) perchlorate, 100 mg of a 10% polymer solution, polymethylvinyltetrazole in chloroform, were added dropwise. To the resulting suspension 8, 0.5 ml of chloroform was added dropwise with stirring and 1.5 mg of nanodiamonds were added. The resulting homogeneous paste was introduced in several steps into a metal cap with a diameter of 5 mm and a height of 2 mm. After evaporation of the solvent, the composition with nanodiamonds completely filled the cap. The charge was dried at 40 ° C.

The resulting photosensitive composition has the following ratio of components: BB: polymer: nanodiamonds = 90: 10: 1.5, i.e. contains ~ 1.4 wt.% nanodiamonds.

Testing the resulting explosive composition for a single laser pulse showed that the minimum initiation energy is 192 μJ.

Other examples (see Table, examples 3-10) were carried out in a similar way, with the difference that various samples of nanodiamonds corresponding to the content of the latter from 0.1 to 5.0 wt.% Were added to the prepared composition. The results of determining the minimum initiation energy are also shown in the Table.

Claims (1)

An initiating explosive composition that is sensitive to low-temperature laser radiation, containing 5-hydrazinotetrazolmercury (II) perchlorate and a polymer, characterized in that it additionally contains detonation synthesis nanodiamonds, and as a polymer contains polymethylvinyltetrazole in the following ratio of components, wt.%: 5-hydrazinotetrazolruti (II) perchlorate 85.7-90.0 polymethylvinyltetrazole 9.5-10.0 detonation synthesis nanodiamonds 0.1-5.0