A study of S-[2-(2-hydroxygenacetyl)thiobenzothiazol-1-yl]dialkyldithiophosphates as novel additives in liquid paraffin

Three S-[2-(2-hydroxygenacetyl)thiobenzothiazol-1-yl]dialkyldithiophosphates were synthesized and their wear and friction behaviors as additives in liquid paraffin were evaluated using a four-ball tester. The thermal degradation tests were conducted to identify their thermal stable properties using thermogravimetry analyzer (TGA) in a Perkin-Elmer model 7 thermal analyzer. The protective film formed on the rubbed surface was investigated by X-ray photoelectron spectroscopy (XPS). Based on the experimental results, the novel additives showed good antiwear ability and friction-reducing properties. The thermal stable properties of three compounds show that the longer the alkyl chain, the more stable. The results of XPS analyses illustrate that the prepared compound as additive in liquid paraffin forms a protective film containing ferric sulfide, ferric sulfate, othophosphate and compounds containing sulfur and nitrogen on the rubbed surface.