Unravelling the Effect of Anthraquinone Metal Salts as Wide-range Plateau Catalysts to Enhance the Combustion Properties of Solid Propellants

Abstract

Novel lead and copper salts based on anthraquinone, including 1,8-dihydroxyanthraquinone,1,4,5,8-tetrahydroxyanthraquinone and 1,8-dihydroxy-4,5-dinitroanthraquinone, were prepared and characterized by Fourier transform infrared spectroscopy (FTIR), elemental analysis (EA), and X-ray fluorescence (XRF). The catalytic effects of these compounds on the decomposition of nitrocellulose (NC) and on the combustion properties of double-base (DB) and composite modified double-base (CMDB) propellants were comprehensively investigated. The results demonstrated that the burning rate is significantly increased (by 200%) in the lower pressure range (2-6 MPa) as compared to the control systems without added anthraquinone-based salts. Concurrently, the pressure exponents (n) were obviously lower, exhibiting a "wide-range plateau" combustion phenomenon in the middle-pressure region. Specifically, for the DB propellants such a plateau region extended from 10 MPa to 16 MPa for n equal to 0.10, from 10 MPa to 18 MPa for n equal to 0.11 and from 8 MPa to 18 MPa when n is 0.05. In the case of RDX-CMDB propellants, the plateau was found to be in the range 6-18 MPa, with n in the range 0.16-0.27, depending on the type of catalyst, in contrast to the reference CMDB sample, which was characterized by n equal to 0.7 for the same pressure range.

A Review of the Catalytic Effects of Lead‐Based Ballistic Modifiers on the Combustion Chemistry of Double Base Propellants

“…Another trend in the work of Zhao et al has been the introduction of energetic functionality to ballistic modifiers in order to increase the combustion rate of the system. These take the form of anthraquinone salts containing metal ions (Pb/Cu), and hydroxyl and nitro groups [73]. These catalysts provide much better modification of the plateau region towards medium gas pressures, as quantified by very low pressure exponents.…”

Towards understanding the catalytic properties of lead-based ballistic modifiers in double base propellants

“…[8][9][10][11][12] To date, only these lead-based compounds support all three burn-rate effects, while the inclusion of other additives, such as copper-based products and carbon black, have been found to further increase the catalytic effect of the lead salts. 2,[12][13][14] The on-going dependence on lead is problematic as this highly toxic element presents hazards in its use and disposal, and impending European Union regulations (Reach -Registration, evaluation, authorisation and restriction of chemicals) 15 will ban their use. Hewkin et al tested a wide range of alternative modifiers including CuO, Fe 2 O 3 , ZnO, Co 2 O 3 and SnO 2 which, while increasing the combustion rate, could not support plateau burning.…”

Transformation of Combustion Nanocatalysts inside Solid Rocket Motor under Various Pressures

“…In order to improve the energy content of this type of propellants, usually maximum 5wt% metal fuels (e.g., Al, Mg, B, and Ni) would be included [5]. The pressure exponent could be further decreased with extended pressure range by use of novel multi-functional catalysts [6]. The experiment phenomenon on combustion performance improvement has been widely reported by use of metal powder and novel catalysts as additives.…”