engleski

The Applicability of Chromatographic Methods in the Investigation of Aging Processes in Double Base Rocket Propellants

The aging of double base rocket propellants (DB rocket propellants) is the result of chemical decomposition reaction and physical processes, causing degradation of a number of relevant propellant properties (such as reduction of stabilizer and nitroglycerine (NG) content, reduction of nitrocellulose (NC) mean molecular mass etc.), which reflects decrease of reliable service life time of DB propellants. This is the reason why the study of processes and consequences (effects) of ageing is so important. In this paper we have studied kinetics of DB rocket propellant decomposition during their artificial ageing, i.e. at elevated temperatures. The kinetic parameters are obtained by measurements of stabilizer/Ethyl Centralite (EC) and NC mean molecular mass reduction, during artificial ageing at temperatures (80, 85 and 90 °C). Consumption of the EC was observed using High Performance Liquid Chromatography (HPLC), while the reductions of the NC mean molecular mass was monitored using Gel Permeation Chromatography (GPC). It has been shown that the artificial ageing of DB propellant causes significant EC consumption and reduction of NC mean molecular mass, from the very beginning of the ageing. The entire EC is consumed after 120 days at 80 °C, followed by the intensive reactions of NC decomposition. The significant changes of NC mean molecular mass start after 60 days of ageing at 90 °C (or ~ 250 days at 80 °C). The results obtained from kinetic data have shown that activation energy of DB propellant decomposition determined on the basis of changes of the NC mean molecular mass is 145.09 kJ/mol, while the activation energy of such decomposition obtained on the basis of EC consumption is 142.98 kJ/mol which is consistent with available literature values [1, 2].

activation energy; artificial ageing; DB rocket propellants; decomposition; Ethyl-Centralite (EC); Gel Permeation Chromatography (GPC); High Performance Liquid Chromatography (HPLC); kinetics of degradation; NC mean molecular mass

nije evidentirano