Synthesis, Characterization and Migration of Ionic Polyferrocenyl Compounds of 5-Ferrocenyl-1H-tetrazole and Their Effects During Combustion

Eighteen ionic polyferrocenyl compounds with 5-ferrocenyl-1H-tetrazolate as anion and mono- and dinuclear ferrocenyl-alkylammonium as cations were synthesized and characterized by H-1 NMR, C-13 NMR, FT-IR, and UV/Vis spectroscopy, and elemental analysis. Molecular structures of three compounds were further confirmed by single-crystal X-ray diffraction. Their thermal stability was evaluated by TG and DSC and found that they are of high thermal stability. The cyclic voltammetry analysis suggested that each of the compounds exhibits only an irreversible redox wave of the ferrocene units in the molecule. Both migration and volatility test results showed that, on comparison with those of Catocene, all tested compounds exhibit much more excellent anti-migration ability and most of the tested compounds have lower volatility. Their effects on the thermal disintegration of ammonium perchlorate (AP), 1,3,5-trinitro-1,3,5-triazacyclohexane (RDX), and 1,2,5,7-tetranitro-1,3,5,7-tetraazacyclooctane (HMX) were measured by DSC. The results revealed that most of the compounds exhibit significant catalytic effects on the thermal degradation of AP and RDX. Particularly, most of the compounds containing one ferrocene unit in their cations show higher activity than that of Catocene. These compounds can be used as alternatives to Catocene in the composite solid propellants.