Antiseizure Properties of Aqueous Solutions of Ethoxylated Sorbitan Esters

Abstract

Influence of compound’s type and concentration of ethoxylated sorbitan ester (ESE) water solutions on their anti-seizure properties was investigated. Ethoxylated sorbitan monolaurate (ESL), ethoxylated sorbitan monostearate (ESS) and ethoxylated sorbitan monooleate (ESO) were used as lubricant additives.
Tribological tests were performed on the four-ball machine, at linearly increasing load (409 N/s) (tribosystem: steel-steel). On the basis of the critical load (the load at the moment of rapid increment of friction torque) anti-seizure properties of the solutions were assessed. The other measured parameter was the seizure load that is load at the moment when friction torque exceeded 10 Nm.
According to the obtained results one can say that addition of ESE to water significantly improves its anti-seizure properties. The measured tribological quantities strongly depend on concentration. 1 %, 4 %, 10 %, 30 %, 50 %, and 100 % solutions were tested. The best anti-seizure properties were observed for 1 %, 4 %, 10 % solutions. The obtained results can be interpreted as a consequence of a formed liquid crystalline structure near to surface. Presence of meso-phases in the tested solutions was confirmed by observations in polarized light and characteristic changes of the viscosity.