Rheological and tribological characteristics of the synthesized lubricants derived from vegetable oils

Abstract

The double bonds in the vegetable oils can be conjungated and Diels-Alder react when they are heated in the existence of the catalyst. The percent of the double bond will decrease and the oxidative stability of the vegetable oils can be ameliorated. Dimmer acid can react with different carbon chain length of alcohols to form dimmer acid esters. A series of dimmer acid esters were synthesized and their rheological characteristics (viscosity, viscosity index, pour point) and tribological characteristics (the coefficient of friction at different load, the characteristic of extreme pressure (P _B), the wear scare diameter (D ^{196 N}_{30 min} ) were evaluated and analyzed. The results showed that the characteristics of Di-iso-octanol dimmer acid ester were the best among the synthesized dimmer esters. It’s a lubricant with good properties (the viscosity is 94.5 mm²/s, the viscosity index is high up to 141 and the pour point is −49t). It is a kind of newly interesting ester type lubricant. Its rheological and tribological characteristics are even better than those of the slap-up synthesized lubricant-pentaerythritol esters (C_7–9 acidate). The FT-IR spectrophotometer was used to analyze the structure of the synthetic esters. Their IR spectra are the same as the typical IR spectrum of ester. The test indicated that Di-iso-octanol dimmer acid ester could be used as a kind of base lubricant with excellent quantity.