Eine Plattform für die Wissenschaft: Bauingenieurwesen, Architektur und Urbanistik
Eine Plattform für die Wissenschaft: Bauingenieurwesen, Architektur und Urbanistik
Time-resolved spectroscopy of initiation and ignition of flash-heated nanoparticle energetic materials
Nanotechnology has brought a great deal of excitement to research in energetic materials (EMs). Nanoparticle EMs have high densities of stored energy and the potential for multifunctionality. Here we discuss research on fundamental mechanisms of initation and ignition of EM with Al or B fuel nanoparticles and Teflon or nitrocellulose (NC) oxidizer. Polybutadiene (PB) was also used as an inert. The thin-film samples were confined between two windows and were activated by flash-heating the metal nanoparticles with picosecond laser pulses. Reactions of isolated nanoparticles with their surroundings were studied by measuring ablation thresholds. A shock-induced polymer dissociation model was needed to explain the growth of the reaction volume surrounding a flash-heated fuel particle. Thicker oxide passivation layers confined the nanoparticle allowing the pressure to build up to higher values during flash-heating. Initiation, as the onset of chemical reactivity, was probed using time-resolved Raman or infrared to monitor disappearance of nitrato (ONO2) of NC or CF2, CF3, or CFO of Teflon. Ignition, the onset of energy-releasing processes, was studied by analyzing time-dependent spectra of emission bursts. In flash-heated Al/Teflon, initiation occurs in about 50 ps and ignition occurs in about 100 ps. In B/Teflon, ignition occurs in about 200 ps. Transient opacity measurements of Al/Teflon suggest that chemical reactivity beyond the initial exothermic formation of AlF occurs within about 5 ns.
Time-resolved spectroscopy of initiation and ignition of flash-heated nanoparticle energetic materials
Nanotechnology has brought a great deal of excitement to research in energetic materials (EMs). Nanoparticle EMs have high densities of stored energy and the potential for multifunctionality. Here we discuss research on fundamental mechanisms of initation and ignition of EM with Al or B fuel nanoparticles and Teflon or nitrocellulose (NC) oxidizer. Polybutadiene (PB) was also used as an inert. The thin-film samples were confined between two windows and were activated by flash-heating the metal nanoparticles with picosecond laser pulses. Reactions of isolated nanoparticles with their surroundings were studied by measuring ablation thresholds. A shock-induced polymer dissociation model was needed to explain the growth of the reaction volume surrounding a flash-heated fuel particle. Thicker oxide passivation layers confined the nanoparticle allowing the pressure to build up to higher values during flash-heating. Initiation, as the onset of chemical reactivity, was probed using time-resolved Raman or infrared to monitor disappearance of nitrato (ONO2) of NC or CF2, CF3, or CFO of Teflon. Ignition, the onset of energy-releasing processes, was studied by analyzing time-dependent spectra of emission bursts. In flash-heated Al/Teflon, initiation occurs in about 50 ps and ignition occurs in about 100 ps. In B/Teflon, ignition occurs in about 200 ps. Transient opacity measurements of Al/Teflon suggest that chemical reactivity beyond the initial exothermic formation of AlF occurs within about 5 ns.
Time-resolved spectroscopy of initiation and ignition of flash-heated nanoparticle energetic materials
Zeitaufgelöste Spektroskopie der Initiierung und Zündung lichtblitzerhitzter energetischer Nanomaterialien
Conner, Rusty W. (Autor:in) / Dlott, Dana D. (Autor:in)
Journal of Physical Chemistry C ; 116 ; 14737-14747
2012
11 Seiten, 12 Bilder, 1 Tabelle, 78 Quellen
Aufsatz (Zeitschrift)
Englisch
Nanopartikel , energetisches Material , Polybutadien , Laserimpuls , Reaktivität (Reaktionsfähigkeit) , Oxidationsmittel , Nitrocellulose , Energiedichte , Aluminium , Bor , Teflon , Pikosekundenbereich , Impulslaser , Raman-Spektrometrie , Zeitauflösung , Infrarotspektrometrie , Opazität , Lichtblitz , Entzündungsverhalten
Friction-induced ignition modeling of energetic materials
| British Library Online Contents | 2009
Computational Analysis of Ignition in Heterogeneous Energetic Materials
| British Library Online Contents | 2014
Suppression of Ignition Over a Heated Metal Surface
| British Library Conference Proceedings | 1995
Suppression of ignition over a heated metal surface
| Tema Archiv | 1998
Hot Surface Ignitions: Ionic Effects in Ignition Initiation
| British Library Conference Proceedings | 1992