Structural influences of ferrocenes on burn rate modification of composite rocket propellants.

Ferrocenes like 2,2'-Bis(ethylferrocenyl)propane (Catocene(R)) are capable to enhance the burning rates of composit propellants significantly without effecting performance, processing and mechanical properties detrimentally. Their disadvantages are a tendency of migration and facilitation of oxidation by air. In this way they spoiled aging behaviour and reliability of the propellant, reduced its lifetime and enhanced its sensitivity. To avoid drawbacks and make a propellant with improved durability, new ferrocene compounds with bulk ligands and functional derivatives like Butacene(r) which are capable of chemical binding to the HTPB polymer were tested in formulations of a fast burning composite propellant. The burning behaviour, processing and mechanical properties of AP/Al/HTPB formulations with different concentrations of ferrocene were evaluated and compared to each other. The efficiency of burn rate enhancement was pointed out in relation to structural features