What is the function of antioxidants in lubricants ?
During the use of lubricants they can both suffer from thermal and/or oxidative stresses, which will degrade the chemical composition of the lubricant’s basestock and deplete the lubricant’s additive package. • Oxidation Is the chemical reaction of a lubricant at elevated temperatures between the dissolved atmospheric oxygen and the base-oil. • During the oxidation, as hydrocarbon molecules will break down, reaction products will be formed, better known as radicals (very reactive chemical compounds). Subsequent reactions of these radicals lead to the formation of peroxides, and must therefore be quenched (see figure 1b) by the antioxidants to preserve the lubricant integrity, or its Remaining Useful Life, RUL. The Remaining Useful Life of a lubricant is the length of engine operating time from when a lubricant is sampled, until the antioxidants are depleted. This results in large changes in the basestock’s physical properties, and formation of insoluble gums or sludge. In the industry
