Relative Dispersion of Catalytic Nanoparticle Additives and AP Particles in Composite Solid Propellant and the Effect on Burning Rate

Abstract

This paper presents current work using nanoparticle metal oxides as catalytic additives in composite solid propellant. The nanoparticles were processed into agglomerated powders and incorporated into ammonium perchlorate (AP) and hydroxyl terminated polybutadiene (HTPB) propellants. Additive effectiveness was evaluated for different AP mass loadings and distribution. Burning rates were evaluated in a strand bomb at incremental pressures between 500-2000 psi for baseline formulations and formulations enhanced with 1% titanium oxide (titania). Additive effectiveness was found to be most sensitive to AP size distribution. Propellants containing portions of fine AP showed a smaller increase in burning rate from the additions of catalytic additives. The theory of relative dispersion between the dispersion of reactions created by the changing AP size and the dispersion of catalytic particles based on the agglomeration of the additives is introduced to explain the presented differences in additive effectiveness.