Effect of Some Catalysts on Combustion of Double-Base Propellants

Supercritical Antisolvent Processing of Nitrocellulose: Downscaling to Nanosize, Reducing Friction Sensitivity and Introducing Burning Rate Catalyst

“…After the burning of the NC matrix with the registered temperatures of 500–900 °C, the desired product was recovered. In line with these results, Denisyuk and Demidova [24] noticed the reduction of SnO 2 to a mixture of SnO and Sn during the combustion of an NC-based propellant. Here, we could assume the reduction of nano-Fe 2 O 3 in our experiments; however the necessary high-temperature flame was not registered.…”

“…Tailoring the burning rate of the double-based propellants, i.e., nitrocellulose-based formulations, is usually performed by adding of 1–10 wt.% of catalysts or inhibitors [23,24]. The general conclusion drawn on the basis of the experience with catalysis of double-based propellants is that carbonaceous skeleton formed above the burning surface promotes the burning rate via the prolongated residence of catalyst particles and increase of heat flux to the condensed phase [24,25,26]. The desired carbonaceous layer can be formed either during combustion of some components, e.g., dinitrotoluene, dibutyl phthalate plasticizers, or by introduced prior to combustion additives (e.g., 0.5–3 wt.% of carbon black in [24]).…”

“…The general conclusion drawn on the basis of the experience with catalysis of double-based propellants is that carbonaceous skeleton formed above the burning surface promotes the burning rate via the prolongated residence of catalyst particles and increase of heat flux to the condensed phase [24,25,26]. The desired carbonaceous layer can be formed either during combustion of some components, e.g., dinitrotoluene, dibutyl phthalate plasticizers, or by introduced prior to combustion additives (e.g., 0.5–3 wt.% of carbon black in [24]). Interestingly, the addition of carbon in the form of carbon nanotubes (CNTs) can increase the burning rate per se, by improving the thermal conductivity [27,28,29].…”

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

“…3 Lead-based ballistic modifiers are commonly used in the form of lead salts of organic acids such as lead acetate, lead salicylate and lead b-resorcylate, or as the oxides PbO, Pb 3 O 4 and PbO 2 . [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.…”

“…10 It is therefore likely that the catalytically active form of the ballistic modifier will be a decomposition product of the lead salts. Furthermore PbO and PbO 2 have been directly proven to be capable of produce plateau burning, 11,12,22 whilst mass spectrometry studies have identified that Pb, PbO, PbO 2 , H 3 PbO 4 and elemental carbon are all formed in the decomposition of lead ballistic modifiers within the combustion process. 9 Of the different lead oxide species, PbO is widely regarded as the most stable form, 23 and so it is likely that other forms of lead oxide will convert to this in the combustion flame.…”