The Tribological Performance of S-[2-(Acetamido) Benzothiazol-1-yl] N,N-Dioctyl Dithiocarbamate as an Additive in Rapeseed Oil

Abstract

A new derivative of benzothiazol, S-[2-(acetamido) benzothiazol-1-yl] N,N-dioctyl dithiocarbamate, was synthesized. The tribological behavior of the synthesized compound as an additive in rapeseed oil was evaluated using a four-ball friction and wear tester, and compared with that of zinc butyloctyl dithiophosphate (ZDDP) and zinc dibutyl dithiocarbamate (ZDTC). The morphologies and elemental chemical states on the worn surfaces of the lubricated GCr15 steel were investigated by means of X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). The biodegradability (fate) and microbial toxicity (effects) measurement of the additive were also performed. The results indicate that the compound possesses excellent load-carrying capacity, antiwear and friction-reducing properties as compared with rapeseed oil alone. The antiwear and friction reduction properties of the novel compound are similar to those of ZDDP and ZDTC; and its load-carrying capacity is similar to ZDTC, but is better than ZDDP. The excellent tribological behavior of the novel compound is attributed to chemical adsorption on and tribochemical reaction with the steel surface, with the generation of a surface protective film composed of FeS, FeSO4, etc. Measurements of biodegradability and microbial toxicity show that the additive has high biodegradability, and microbial toxicity needed to be further lowered.