Pulsed Laser Induced Decomposition of Energetic Polymers: Comparison of ultraviolet (355 nm) and infrared (9.3 μm) initiation

Haas, Yehuda; Ben-Eliahu, Yeshayahu; Welner, Shmuel

doi:10.1002/prep.19960210509

Cited by 10 publications

(13 citation statements)

References 21 publications

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“…Some work focuses on propellants and pyrotechnics (Assovskii & Leipunskii 1980;Haas et al . 1994;Haas & ben Eliahu 1996;Østmark & Roman 1993;Radenac et al . 1998;Saito et al .…”

Section: Ignition or Initiation By Direct Irradiation (A) Early Researchmentioning

confidence: 99%

On the laser ignition and initiation of explosives

Bourne¹

2001

Proc. R. Soc. Lond. A

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Energetic materials are conventionally ignited by the application of heat to some part of an explosive target. This is most often provided by a flame or by electrical heating using a resistive wire. The material responds by thermally heating and starting a burning zone, which spreads out from the ignition point generating gas. In some cases this zone can accelerate (due to the effect of this gas) into a reactive shock wave, termed detonation. Lasers are used in a variety of applications to thermal heat a range of materials, and thus seem an obvious candidate to trigger chemical reaction in energetic ones. A light pulse offers several advantages over an electrical one, since it may be delivered down a path both immune to electrical effects and chemically stable. Thus, the triggering of safety apparatus (such as the firing of bolts on aircraft exits) represents a major thrust in the development of laser-triggered explosive devices. The energy of the pulse may be used in one of two ways to achieve these effects. In the first, the laser is shone directly upon the chemical medium, which absorbs the light at discrete wavelengths. In the second, it is used to vaporize a metallic flyer that is launched to impact on a target creating a high-pressure zone. Either mechanism starts the required reaction. However, when the pulse is delivered directly to the material, detonation is found to proceed immediately with no transition via burning. This makes the process inexplicable using present concepts. This review will address a range of the experiments conducted and theories developed for this novel field. However, it should be emphasized that the fundamental mechanisms remain to be fully explained making the application both academically stimulating as well as industrially important.

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“…Some work focuses on propellants and pyrotechnics (Assovskii & Leipunskii 1980;Haas et al . 1994;Haas & ben Eliahu 1996;Østmark & Roman 1993;Radenac et al . 1998;Saito et al .…”

Section: Ignition or Initiation By Direct Irradiation (A) Early Researchmentioning

confidence: 99%

On the laser ignition and initiation of explosives

Bourne¹

2001

Proc. R. Soc. Lond. A

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“…[2][3][4][5][6][7][8][9][10][11][12][13][14][15] However, a few studies found that a laser ablated energetic polymer (glycidyl azide polymer [GAP]) produced a faster shock wave than nonenergetic polymers. [16][17][18][19] The increased shock wave velocity was attributed to the higher decomposition enthalpy of GAP; the pulsed laser initiated a self-sustaining exothermic reaction resulting in rapid formation of gaseous products. More recently, Roy et al 20 measured spatially and temporally resolved temperatures behind an expanding laser-induced shock wave to demonstrate differences in energy release between reacting aluminum nanoparticle formulations.…”

Section: Introductionmentioning

confidence: 99%

Influence of exothermic chemical reactions on laser-induced shock waves

Gottfried

2014

Phys. Chem. Chem. Phys.

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Differences in the excitation of non-energetic and energetic residues with a 900 mJ, 6 ns laser pulse (1064 nm) have been investigated. Emission from the laser-induced plasma of energetic materials (e.g. triaminotrinitrobenzene [TATB], cyclotrimethylene trinitramine [RDX], and hexanitrohexaazaisowurtzitane [CL-20]) is significantly reduced compared to non-energetic materials (e.g. sugar, melamine, and l-glutamine). Expansion of the resulting laser-induced shock wave into the air above the sample surface was imaged on a microsecond timescale with a high-speed camera recording multiple frames from each laser shot; the excitation of energetic materials produces larger heat-affected zones in the surrounding atmosphere (facilitating deflagration of particles ejected from the sample surface), results in the formation of additional shock fronts, and generates faster external shock front velocities (>750 m s(-1)) compared to non-energetic materials (550-600 m s(-1)). Non-explosive materials that undergo exothermic chemical reactions in air at high temperatures such as ammonium nitrate and magnesium sulfate produce shock velocities which exceed those of the inert materials but are less than those generated by the exothermic reactions of explosive materials (650-700 m s(-1)). The most powerful explosives produced the highest shock velocities. A comparison to several existing shock models demonstrated that no single model describes the shock propagation for both non-energetic and energetic materials. The influence of the exothermic chemical reactions initiated by the pulsed laser on the velocity of the laser-induced shock waves has thus been demonstrated for the first time.

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“…Apart from degradation in solution, the pulsed‐laser technique has been used to study the photoetching, ablation, and deposition of polymer thin films onto surfaces 23–26. The theoretical model for the process of ablation considers it to be a nonstationary thermodestruction process that follows an Arrhenius equation, where degradation occurs for every laser pulse 27.…”

Section: Introductionmentioning

confidence: 99%

Photodegradation of poly(vinyl alcohol) under UV and pulsed‐laser irradiation in aqueous solution

Vijayalakshmi

Madras

2006

J of Applied Polymer Sci

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ABSTRACT:The photodegradation of poly(vinyl alcohol) (PVA) in aqueous solution was investigated under UV exposure and pulsed-laser irradiation. The degradation under UV exposure was studied at different pH values and with the addition of potassium chloride and potassium dichromate. The pulsed-laser degradation of PVA was investigated with a Nd : YAG laser, operating at a wavelength of 266 nm with about 6-ns pulses. The pulsed-laser degradation was studied at different polymer concentrations and light intensities. Samples were analyzed by gel permeation chromatography. The degradation rate coefficients were determined by the application of a continuous distribution model. The photodegradation rates under UV exposure were highest at extremes of pH and were greatly enhanced by the addition of potassium chloride and potassium dichromate. The pulsed-laser degradation of the polymer decreased with increasing polymer concentration, although a threshold light intensity was required to initiate the degradation process.

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Pulsed Laser Induced Decomposition of Energetic Polymers: Comparison of ultraviolet (355 nm) and infrared (9.3 μm) initiation

Cited by 10 publications

References 21 publications

On the laser ignition and initiation of explosives

On the laser ignition and initiation of explosives

Influence of exothermic chemical reactions on laser-induced shock waves

Photodegradation of poly(vinyl alcohol) under UV and pulsed‐laser irradiation in aqueous solution

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