Mesoporous Copper Oxide as a New Combustion Catalyst for Composite Propellants

The use of powder additives to modify the burning rates of solid propellants and other energetic materials has been the topic of much study for several decades. This paper reports the discovery of the enhancement of the performance of ammonium perchlorate-based composite propellants by means of employing mesoporous copper oxide powder as a new burning rate catalyst in comparison to conventional (nonporous) copper oxide fillers. The burning rate measurements, obtained by the strand burner method, show that, with the addition of mesoporous fillers of copper oxide in aluminized composite propellants, higher rates (in excess of 22 mm/s at 7 MPa) are found over a broad pressure range. It was noticed that these high burning rates were accompanied by a more stable combustion, decreasing considerably the pressure index (0.40 versus 0.55). The thermal characterization of these highly energetic composite materials was also carried out by differential scanning calorimetry and thermogravimetric analysis, demonstrating that the incorporation of mesoporous copper oxide particles in the formulations improves their combustion behavior, shifting the temperature decomposition peak toward a lower temperature and decreasing the activation energy. The results presented here reveal the advantages exhibited by the use of these mesoporous particles as an additive for solid rocket propulsion technology.