Studies on the effect of nano-MnO2 in HTPB-based composite propellant formulations

Abstract

Various propellant compositions were prepared incorporating fully characterized nano-sized manganese dioxide, from 0.25 wt.% to 1.0 wt.%, in HTPB/AP/Al-based composite propellant formulations having 86 wt.% of solid loading, and its effects on the viscosity build-up, thermal, mechanical and ballistic properties were studied. The findings revealed that on increasing the percentage of nano-MnO2 in the composition, there was an increase in the end of mix viscosity, the modulus and tensile strength, while the elongation decreased accordingly. The data on the thermal properties revealed a reduction in the decomposition temperature of ammonium perchlorate (AP) as well as of the formulations based on it. The data on the ballistic properties revealed that there is an enhancement in the burning rate from 6.11 mm/s (reference composition) to 7.54 mm/s at 6.86 MPa (a 23% enhancement in the burning rate) and an increase in the pressure exponent from 0.35 (reference composition) to 0.42 with 1.0 wt.% nano-MnO2.