Pentaerythritol rosin ester as an environmentally friendly multifunctional additive in vegetable oil-based lubricant

Abietic acid is an abundant renewable natural resource. Pentaerythritol rosin ester (PRE), which is synthesized by esterification of abietic acid and pentaerythritol, is notably environmentally friendly. In our study, we first report PRE as an environmentally friendly multifunctional additive in vegetable oil-based lubricant. The dynamic viscosity, kinematic viscosity, thermal stability and oxidation stability were investigated. The dynamic viscosity of rapeseed oil (RO) and soybean oil (SO) increased by 136.11% and 179.3% at 25 degrees C when 20 wt% of PRE was added. The viscosity results indicated that PRE can significantly increase the viscosity of RO and SO base oils to expand their range of applications. Moreover, lubricant samples with PRE had higher thermal stability and oxidation stability compared with pure RO and SO. The onset temperature (OT) of oxidation of RO and SO increased by 7.7 degrees C and 12.6 degrees C, respectively, when the concentration of PRE was 20 wt%. The oxidation induction time (OIT) of RO and SO increased by 305% and 124%, respectively, when the concentration of PRE was 20 wt%. Therefore, environmentally friendly multifunctional additive of PRE may be a potential alternative to the traditional additives in the preparation of eco-friendly bio-based lubricant.