Triazinyl-containing polysulfides as additives in biodegradable grease Tribological studies of S-N type

Purpose - This paper sets out to study tribological properties, anticorrosive performances and thermal stabilities of two novel S-N type triazinylcontaining polysulfides {Bis[2,4-bis(diethylamino)-s-triazin-6-yl] polysulfide (BBET-PS) and Bis[2,4-bis(di-n-butylamino)-s-triazin-6-yl] polysulfide (BBBT-PS)) as additives in biodegradable grease, and to estimate the tribochemical mechanism. Design/methodology/approach - Extreme pressure (EP) and anti-wear (AW) properties of two compounds at different addition concentration were evaluated using a four-ball machine. Their wear scar was analyzed with X-ray photoelectron spectroscopy (XPS) and a scanning electron microscope. Findings - Two novel S-N type triazinyl-containing polysulfides possess excellent load-carrying capacity, good AW and show good corrosion-inhibiting performance. The thermal stability of BBB-PS is better than that of BBE-PS. According to the XPS results, the triazinyl-containing polysuffides react with the metal to generate a surface protective film consisting of sulfate, FeS and absorbed compounds containing organic-N. Research limitations/implications - The antioxidant and biodegradability of the two novel compounds were not investigated. Practical implications - Two effective EP and AW additives were synthesized, and maybe potentially industrial applied lubricating grease additives. Originality/value - The achievement of this study is the synthesis of two triazinyl-containing polysulfides, which can be effective additives to improve the tribological performance of biodegradable grease.