Pyrolysis-atmospheric pressure chemical ionization was used to study the thermal decomposition of the energetic material cyclotrimethylenetrinitramine (RDX) and characterization of the individual molecular ion products was accomplished by tandem mass spectrometry. The analysis was aided with pyrolysis mass spectra of the (''N)-and perdeuterated RDX isotopes, and molecular formulae were derived for the m/z 46, 60, 74, 75, 85 and 98 molecular ions in the RDX pyrolysis mass spectrum. Equivalent fragments between the daughter ion mass spectra of the unlabeled and labeled RDX were determined in order to define a structure for each pyrolysis feature. Daughter ion mass spectra of pure reference compounds confirmed the identity of five of the six molecular ions, Perdeuterated RDX analyses provided evidence that m/z 74 and 75 are N,N-dimethylformamide and N-nitrosodimethylamine, respectively; m/z 46, 60 and 85 were identified as the protonated forms of formamide, N-methylformamide and dimethylaminoacetonitrile, respectively.

No abstract

Solid propellant characterization has been performed with the use of three Fourier transform infrared (FT-IR) techniques: FT-IR-microscopy (FT-IR-mic), attenuated total reflectance/FT-IR (ATR/FT-IR) spectroscopy, and desorption/gas chromatography/FT-IR (D/GC/FT-IR) spectroscopy as well as thermogravimetric analysis (TGA). Emphasis was placed on examination of the content and behavior of plasticizer (bis-2,2-dinitropropyl acetal/formal, BDNPA/F) in propellant samples characterized over a 300-day period. Levels of residual solvent and other desorbable materials were examined as well. The following conclusions were made: there are significantly higher levels of both plasticizer and polymeric binder at extruded surfaces than in the interior of propellant grains; the rate of plasticizer migration in binder alone depends on the CAB:NC (cellulose acetate butyrate: nitrocellulose) ratio; and plasticizer evaporation and diffusional migration are negligible for all but one of the samples analyzed, suggesting that plasticizer is probably not responsible for observed aging phenomena. Levels of residual solvent and other minor components were observed to decrease with time under both ambient and accelerated aging conditions and may be related to aging phenomena.

A calculation is described for determining water molecule Frr force constants from observed HOD, H2O, and D2O vibrational frequencies. The calculations for water in the vapor and in the hydrates MnCl2·2H2O, FeCl2·2H2O, CoCl2·2H2O, and CuCl2·2H2O indicate a large increase in Frr with hydrogen bonding. Various contributions to Frr are considered, and its increase is attributed to an enhancement of the effective charge on water hydrogens with increased hydrogen bonding.

No abstract

Laser and radiative ignition of 24 solid propellants and explosives was analyzed. The effect of ignition criterion used to calculate ignition delays from models was evaluated. Values for the optical parameters reflection, R A and absorption, k^ coefficients at wavelengths 0.36-1,1.06 and 10.6 urn were summarized. Effects of in-depth absorption and vaporization were considered. Methods for determining the relation of ignition delays for conductive heating (R x = 1, k A = infinity) and radiative heating at various wavelengths are presented. Methods for deriving kinetic parameters for the ignition and vaporization mechanisms for RDX-based materials were developed. Changes in the ignition mechanism at high radiative flux levels are discussed. A summary of the minimum flux levels needed for ignition and the Arrhenius kinetic parameters determined from ignition delay measurements with several energetic materials is presented. List of Figures viiList of Tables ix IX INTENTIONALLY LEFT BLANK.

No abstract

No abstract