Study of degradation of marine engine oils using Fourier transform infrared spectroscopy

The purpose of the work was to study the processes of degradation of hydrocarbons in marine motor oils and depletion of the anti-wear additive zinc dialkyldithiophosphate using Fourier transform infrared spectroscopy. The study is one of the preliminary analyzes by this method of several fresh and used marine engine oils, which have not previously been studied for aging during engine operation. Changes in the composition of used oils compared to fresh oils were analyzed. The absorption intensities of impurities of various substances in the IR spectra of the studied motor oils were measured. The possibility of identifying oil by the presence of additive absorption lines has been confirmed. The data obtained are a valuable source of information on the processes of oxidation, nitration and sulfatization of hydrocarbons of the tngine oils, and on the depletion of improving additives contained in the oil. The results obtained in the work can be used in the future to build an expert system for determining the parameters of unknown engine oils.