Impact of oleoyl glycine on biodegradability and lubricity of lubricating oil

Abstract

Purpose

The purpose of this paper is to understand the impacts of oleoyl glycine on biodegradation, friction and wear performances of a mineral lubricating oil.

Design/methodology/approach

The biodegradabilities of a neat oil and its formulations with oleoyl glycine were evaluated on a biodegradation tester and the microbial characters in the biodegradation sewage observed through a microscope. Also, the friction and wear performances of neat oil and the formulated oil were determined on a four‐ball tribometer. The morphologies and tribochemical features of the worn surfaces were analyzed by scanning electron microscopy and X‐ray photoelectron spectroscopy.

Findings

Oleoyl glycine markedly enhanced biodegradation of unreadily biodegradable mineral oil and effectively improved its anti‐wear and friction‐reducing abilities. The enhancement of biodegradability of the mineral oil was preliminarily ascribed to the increment of microbial populations in the biodegradation processes, while the improvement of anti‐wear and friction‐reducing abilities was mainly attributed to the formation of a boundary adsorption film of oleoyl glycine on the friction surfaces.

Originality/value

Oleoyl glycine is a biodegradable and low eco‐toxic compound. The authors' work has shown that oleoyl glycine is effective in improving biodegradability and tribological performances of mineral lubricants. Enhancing biodegradability of petroleum‐based lubricants by additives is a new attempt. The paper has significance for improving ecological and tribological performances of mineral lubricants, even for developing petroleum‐based biodegradable lubricants.

Citation

Chen, B., Huang, W. and Fang, J. (2012), "Impact of oleoyl glycine on biodegradability and lubricity of lubricating oil", Industrial Lubrication and Tribology, Vol. 64 No. 3, pp. 122-127. https://doi.org/10.1108/00368791211218614