The Curing Mechanism of Hydroxylammonium Nitrate‐Based Electrically Controlled Solid Propellant

ABSTRACT At room temperature, the mixture of hydroxylamine nitrate (HAN) solution and polyvinyl alcohol (PVA) powder solidifies to form an electrically controlled solid propellant. Investigating its curing mechanism can provide important guidance for formulation design. This study systematically examines the effects of different HAN solution concentrations, varying PVA contents, and molecular weights on the curing characteristics of the propellant. Multiple characterization techniques, including compression tests, thermogravimetric analysis, Fourier‐transform infrared spectroscopy, and scanning electron microscopy, were employed to thoroughly investigate the curing mechanism of HAN‐electrically controlled solid propellants (HAN‐ECSP). The results indicate that HAN can form stronger hydrogen bonds with PVA, and high‐concentration HAN solutions effectively promote the dissolution of PVA, leading to the formation of a uniform and dense three‐dimensional network structure. This structure not only imparts excellent structural stability to the propellant but also provides good self‐recovery properties. However, low PVA content and molecular weight result in insufficient crystalline regions within the propellant, with inadequate entanglement between PVA chains, which adversely affects the curing performance. To achieve optimal curing performance for HAN‐ECSP, the HAN concentration should be maintained above 80%, the PVA content should be at least 15%, and the PVA molecular weight should exceed 166 000 g/mol.