Abstract

Composites of rhenium (ReNP) and rhenium-copper nanoparticles (ReCuNP) were studied as catalysts for the decomposition of the oxidizer ammonium perchlorate (AP) for composite solid propellants. Both composites were prepared by reducing ammonium perrhenate (NH4ReO4) and copper chloride (CuCl2) in the presence of polyamidoamine (PAMAM) dendrimers. The PAMAM-based nanostructures were characterized by transmission electron microscopy (TEM), high resolution TEM, and X-ray photoelectron spectroscopy. ReNP@PAMAM samples showed rhenium clusters and partially oxidized spherical nanoparticles of approx. 1 nm in diameter, while ReCuNP@PAMAM comprised nanoparticles of 6 nm in average size with different shapes and high-size dispersion. The computational description demonstrated the higher stability of the interaction between copper and PAMAM than perrhenate anion due to the charge transfer from the dendrimer to the cation. The materials were evaluated for the catalytic decomposition of AP by calorimetry. The catalytic performance of ReCuNP@PAMAM was superior to that of ReNP@PAMAM, lowering the decomposition of AP at high temperatures. However, the latter composite increased the energy release drastically due to the exothermic oxidation of rhenium metal.