Development of biodegradable lubricating grease for application in specialized equipment operating under marine environmental conditions

Lubricating greases play a crucial role in protecting and maintaining the stable operation of equipment, particularly under the harsh and corrosive conditions of marine environments. Most currently available greases are formulated from mineral oils, which are non-biodegradable and pose serious environmental pollution risks. In response to the increasing demand for environmentally friendly alternatives, especially in marine environments where various military devices operate, the development of biodegradable lubricating greases has become a necessity. This study presents the synthesis and evaluation of a biodegradable grease formulated using castor oil as the base oil, lithium 12-hydroxystearate soap as the thickener, and functional additives with anti-corrosion and anti-wear properties. The grease was prepared with a thickener-to-base oil ratio of 14:86 wt.% and temperature processed at 220–230 oC, resulting in a stable structure and high homogeneity. Salt spray test results demonstrated a significant improvement in metal surface protection. Additionally, the grease exhibited a load-carrying capacity of 315 kg and a biodegradability exceeding 70%. The results indicate that the grease offers excellent lubricating and protective properties and high biodegradability, making it suitable for equipment operating in marine environments.