ABSTRACT
Failures in moving parts of mechanical systems can be mitigated or eliminated using appropriate lubricants. While conventional fossil-derived mineral oil-based lubricants have served the mechanical industry for this purpose for over a century, increasingly stringent environmental norms have tended to incentivize eco-friendly and biodegradable base oil additives for lubrication. In this chapter, we have first compared the tribological efficacy of fossil-based and bio-based base stocks (petroleum-derived mineral oils and naturally occurring tree-borne oils) utilizing a combined approach of experimental simulations and molecular modeling to demonstrate that polar end groups in the case of a tree-borne oil-derived lubricant interact strongly with, diffuse slowly from and adsorb efficiently over the substrate, thereby providing superior tribo-performance as compare to fossil derived when compared to mineral oil based lubricants. Having established this point, we then reviewed the extensive literature on using such esters of naturally occurring tree-borne oils. We observed that polyol esters of fatty acids dominate the application landscape. In such lubricant esters, every oxygen atom present is part of an ester linkage. This raises the question of whether other oxygen atom environments, such as ether linkages, could enhance bio-derived lubricants’ performance in specific applications.
