Synthesis of Ferrocene-Based Morpholine Compounds and Their Catalytic Impact on Ammonium Perchlorate Decomposition for Advanced Composite Solid Propellant

Ferrocene-based compounds are widely used as burning rate catalysts (BRCs) in composite solid propellants (CSPs) due to their efficient performances in the thermal decomposition of ammonium perchlorate (AP). However, on prolong storage ferrocene-based BRCs favors migration in the propellant matrix. To address this issue, ferrocenyl (Fc) morpholine compounds (Fc-MORP-1, Fc-MORP-2 and Fc-MORP-3) were synthesized. The structure of Fc-MORPs was characterized by UV–Vis, FT-IR and 1 H-NMR spectroscopy, while the catalytic activities were examined through thermogravimetric (TG) and differential thermogravimetric (DTG) techniques. Results reveal that pure AP decomposed at 415.28 °C and after mixing with 1 wt.% of Fc-MORP-1, Fc-MORP-2 and Fc-MORP-3, the decomposition temperature of AP reduced to 382.50 °C, 380.42 °C and 396.62, respectively, showing that Fc-MORP-2 shows good catalytic performance. Anti-migration studies revealed that Fc-MORP-3 shows the best anti-migration performance in simulated CSP. In addition, the combustion performances were investigated by burning AP-hydroxyl-terminated polybutadiene (HTPB)-based simulated propellant. The results showed that Fc-MORP-2 had effectively reduced the burning time of the simulated AP-HTPB propellant from 24 s (sec) to 10 sec.