| As burning rate (BR) catalysts, ferrocene derivatives are currently mostly used in solid propellant, especially in the hydroxyl-terminated polybutadiene/aluminum/ammonium perchlorate (HTPB/A1/AP) composite solid propellants, and play an important role in various kinds of middle-and long-range missile propulsion systems, due to their excellent combustion properties. Although the currently commercialized ferrocene burning rate catalysts such as n-Butylferrocene (NBF), tert-butylferrocene (TBF),2,2-bis(ethylferrocenyl)propane (Catocene), n-octylferrocene and bis(ethylferrocenyl)methane (Hycat 6D), can greatly improve the burning rates of HTPB propellants, they exist the defects such as strong migratory tendency and volatility in applications. The most urgent task in current situation is to develop new generation of ferrocene-based BR catalysts with high catalytic efficiency and thermal stability, stable electrochemical properties and low mobility.To overcome the drawbacks those current ferrocene-based BR catalysts exist, in this paper we introduced the unique advantages (low vapor-pressure, volatility and mobility, high formation enthalpy and low pollution) of nitrogen-rich energetic ionic compounds into ferrocene and its derivatives, and designed and synthesized a series of new type of nitrogen-rich energetic ionic ferrocenyazole compounds. The main research contents of this thesis are as follows:(1) (1-ferrocenylmethyl)alkylimidazolium/triazolium iodides with different alkyl chain (n= 1-4) and silver nitrate, sodium picrate, potassium 1,1,3,3-tetracyanopropenide, pyridinium 1,1,2,3,3-pentacyanopropenide and tetraethylammonium 1,1,2,5,6,6-hexacyano-3,4-diazahexa-dienide were chosen as raw materials,21 nitrogen-rich energetic ionic ferroceneazole compounds were designed and synthesized. During synthetic processes the environment-friendly and cheap solvent water, together with minimum amount of methanol in some cases, were used as medium. And the reactions were conducted at room temperature and atmospheric pressure with simple synthetic steps, easy separation and purification and high yield. The new compounds were characterized by 1HNMR, 13CNMR, EA, single-crystal X-ray diffraction, FT-IR, UV/Vis and M.p. determination and supported the molecular structures of our desired products.(2) Thermal behaviors of the compounds 1-H2O-21 were investigated by TG/DSC methods. It can be found from the results that the thermal decomposition peak temperature of 1·H2O-8> 172.2 ?,9-16> 205.4 ?, while NBF is 64.2 ?, indicating that the thermal stability of the compounds 1·H2O-21 are higher than that of NBF. The alkyl chain lengths in the imidazole/triazole rings exert no significant effect on their thermal stability.(3) The redox properties of the new compounds 1·H2O-21 were studied by cyclicvoltammetry techniques. It can be found that Ep1/2 of the new compounds are in the range of 578-649 mV, higher by nearly 200 mV than those of NBF (394 mV), TBF (378 mV) and Catocene (347 mV). The electrochemical properties of the new compounds indicated that these compounds exhibit quasi-reversible redox systems and are more difficult to be oxidized than the neutral ferrocene derivatives.(4) The mobility of some selected compounds (3,4,5,14 and 19) were determined and compared with that of Catocene. It can be found that the total migration percentages of 3,4,5,14 and 19 aged for 7 days at 70 ? are 2.77%,2.82%,2.85%,2.68% and 0.95%, while that of Catocene is 32.86%. Obviously, these compounds have lower migration tendency and the migration rates decrease with increase of molecular weight, increases with elongation of the alkyl chains in the imidazole/triazole rings.(5) The catalytic performances of the new compounds and NBF for thermal degradation of the main components of solid propellants such as 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 evaluated by DSC technique. It was found that both the high-temperature decomposition stage (HTD) and the low-temperature decomposition stage (LTD) of AP are changed dramatically. The endothermic process of the AP peaked at 429.3 ? disappears and new exothermic processes are shown peaked in the region of 350.1-365.9 ? (63.4-88.8 ? downwards-shift). The released heat of AP is in the ranges of-1042.9-2164.0 J·g-1 for addition of optimum weight percentages (4 wt.% or 5 wt.%) of the new compounds. While, the released heat of AP is -643.6 J-g-1 and-233.0 J·g-1 for addition of NBF (4 wt.% and 5 wt.%). Therefore, these compounds have more significantly catalytic effect for AP than NBF. In addition, except compounds 7 other compounds have great catalytic effect on thermal degradation of RDX, and most of the compounds also have certain ability of catalytic performance for HMX.In summary, the 21 new nitrogen-rich energetic ionic ferrocenylazole compounds show highly combustion catalytic properties for thermal degradation of main components of solid propellants. In the meanwhile they have the advantage of low mobility, high thermal stability and better anti-oxidation ability, satisfying the basic requirements of a commercialized burning rate catalyst and showing potential application values. |
PDF Full Text Request