Document Type : compile
Authors
1
PhD candidate/ University of Isfahan
2
Product Engineering and Development Unit, Sepahan Oil Company, Isfahan, 8143864755, Iran
10.22063/basparesh.2025.35723.1744
Abstract
Foam formation in lubricants is a significant challenge in industrial systems, primarily caused by the accumulation and stabilization of air bubbles within the fluid. The formation and persistence of foam are influenced by the chemical and physical properties of the lubricant, as well as operational conditions such as temperature, pressure, and oil circulation speed. Foam can also be promoted by certain additives, including detergents, antioxidants, anti-corrosion agents, and dispersants, many of which act as surfactants and stabilize bubbles by lowering the interfacial tension between gas and liquid phases. The detrimental effects of foam include reduced lubrication efficiency, impaired cooling and heat dissipation, accelerated oil oxidation, increased corrosion, disruption of oil flow, and potential safety hazards such as leakage and fire risk. Polymers play a crucial role as antifoaming agents in lubricants. These compounds, such as polydimethylsiloxane, polyethylene glycol, and specific copolymers, improve lubricant performance by reducing surface tension, destabilizing foam films, and preventing air ingress. The mechanisms by which polymeric antifoams operate include local reduction of surface tension, disruption of foam film elasticity, and facilitation of liquid drainage from bubbles. Recent studies have shown that modifying polymer structures and incorporating nanoparticles can significantly enhance antifoaming performance and thermal stability. This review discusses the mechanisms of foam formation, factors influencing foam stability, and the chemistry and application of various polymeric antifoaming agents used in lubricants.
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