Abstract: 2,2’, 4,4’, 6,6’- hexanitrostilbene (HNS) is an energetic material, a nitroaromatic compound, with thermal and chemical stabilities, which is employed in the aerospace industry. In this work, the Arrhenius parameters (activation energy and pre-exponential factor) of thermal decomposition reaction were studied and the results were compared with the values reported in the literature. The Kissinger method, applied to DSC’s nonisothermal data of the decomposition temperature was chosen for this study. The activation energy determined for the thermal decomposition of HNS revealed values from 428 kJ.mol-1 to 477 kJ.mol-1, under the experimental conditions employed.

Abstract: A new methodology was developed to characterize and to quantify the polymer content in PBX (HMX/Viton) by Fourier Transform Infrared Spectroscopy (FT-IR), using the Termogravimetric analysis (TG) as reference techniques for the quantitative method. The quantification methodology, proposed by us, using the Fourier transform infrared-attenuated total reflectance (FT-IR/ATR) showed excellent results, being faster than the usual methodologies and can eliminate the generation of chemical residues.

A new method has been developed for determining the content of mixtures of octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX) and hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX), the HMX/RDX ratio, in explosive compositions by Fourier transform infrared spectroscopy (FT-IR), in the regions MIR (mid infrared) and NIR (near infrared) with reference values obtained by chromatographic analysis (HPLC). Plots of relative MIR (A917 / A783) or NIR absorbance values (A4412 / A4317) versus HMX/RDX ratio determined by HPLC analysis revealed good linear relationships.

Técnicas FT-IR de transmissão, reflexão e fotoacústica (PAS) foram utilizadas para a caracterização da cobertura polimérica do hexahidro-1,3,5-trinitro-1,3,5-triazina (RDX) usando um poliuretano (Estane). Verificou-se no decorrer deste trabalho que, embora seja possível observar as bandas do polímero por meio das diferentes técnicas, as de transmissão (filme vazado) e fotoacústica foram aquelas que melhor evidenciaram as absorções do poliuretano na amostra analisada da cobertura polimérica do material energético. Entre as técnicas consideradas de análise de superfície, a espectroscopia PAS apresentou melhor resultado, provavelmente em função da espessura de poucos micra da camada polimérica.

The transmission, reflection and photoacoustic FTIR techniques have been used for characterization of polymeric coating of hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) using a polyurethane (Estane). Although the bands characteristic of the polymer were indicated by the various techniques, the transmission (casting film) and photoacoustic techniques showed better evidence of polyurethane absorptions in the polymer coating of energetic material. Among the surface-sensitive techniques, PAS spectroscopy shows better result, probably because the polymer coating is at few microns from the surface.