An investigation of propellant stabiliser degradation products.
Chemical stabilisers are incorporated into nitrate ester based propellant
formulations to react with the initial propellant decomposition products, preventing the
onset of autocatalytic deterioration of these energetic constituents. As a result of these
interactions the stabiliser forms a number of derivatives. Sources of these propellant
stabiliser degradation products are vital for investigating the course of propellant
breakdown and for the validation of several established stability tests.
Synthetic methodologies have been developed which yield targeted derivatives of
diphenylamine via catalysed and uncatalysed nucleophilic aromatic substitutions in
conjunction with standard nitrosating techniques.
Ethylcentralite, used in double or triple base propellants, reacts depending on
stabiliser concentration, to give two distinct groups of degradation products. Those based
on the N-ethylaniline nucleus and those based on the parent stabiliser. The derivatives
based on N-ethylaniline have been synthesised utilising a variety of synthetic approaches
including phase transfer catalysed N-alkylation, while the utility of urea synthesis
employing the reaction between anilines and isocyanates has been evaluated as a possible
route towards the second group of ethylcentralite propellant stabiliser degradation
High performance liquid chromatographic techniques have been developed for the
quantitative assay of the diphenylamine and ethylcentralite stabiliser derivatives
synthesised. Preliminary analysis of different single base propellants, stabilised by
diphenylamine, indicate markedly different degrative product profiles for each of the
samples studiedFinally an investigation of a resorcinol stabilised model propellant system has
provided evidence that 2-nitroresorcinol, 4-nitroresorcinol and lacmosol are propellant
stabiliser degradation products of the aforementioned stabiliser