Antifoaming Agent for Lubricating Oil: Preparation, Mechanism and Application

Abstract

In the process of using lubricating oil, it is inevitable that bubbles will be produced, which can not only accelerate the oil’s oxidation and shorten the oil change cycle but also reduce its fluidity and lubricity, aggravate the wear of mechanical parts and produce an air lock that interrupts the oil pump supply and causes an oil shortage accident. This paper mainly and comprehensively discusses the foaming process and its harm, the defoaming mechanism and defoaming method of lubricating oil, more specifically, the synthesis, application, advantages, disadvantages and current situation of three kinds of chemical defoaming agents, namely silicone defoaming agent, non-silicone defoaming agent and compound defoaming agent. Finally, the paper looks forward to the future development of special defoaming agents for lubricating oil.

Process Development for the Sustainable and Economic Production of Biobased and Biodegradable High-Performance Lubricants

“… A small portion of silicone oil was added to be on the safe side to prevent potential foaming. In the reactions shown, however, this would not be mandatory, as excessive foaming only leads to problems when producing high-viscosity oils by extending the reaction time to >40 h. On the other hand, silicone oil is often added to lubricants as a defoamer and, thus, its use in the final product would not represent a problem or raise purification concerns since there is no need to remove this additive. − In the field of lubricants, one of the most relevant parameters for application is viscosity, and in our case it directly correlates to the degree of polymerization (see the Supporting Information, Figure S2). We were pleased to find a strong relationship between the reaction time and viscosity, giving us the opportunity to produce low-viscosity oligomers (viscosity at 40 °C: 67.9 mm 2 s –1 ) as well as high-viscosity fatty esters (viscosity at 40 °C: 407.2 mm 2 s –1 ) within the same plant and within the same type of process just by changing the reaction time (Figure A).…”

Structure–activity relationship study of anti-wear additives in rapeseed oil based on machine learning and logistic regression

“…Commonly used lubricant additives include dispersants, detergents, anti-foam agents, viscosity index improvers, antioxidants, and anti-wear agents. 6,7 The purpose of anti-wear agents is to reduce wear on metallic surfaces, thereby prolonging the life of the engine. Initially, anti-wear agents were mainly composed of inorganic compounds, such as lead chloride and molybdenum disulfide.…”

Microscopic Understanding of Interfacial Performance and Antifoaming Mechanism of REP Type Block Polyether Nonionic Surfactants

“…While most of the currently employed defoamers include mineral oil, fatty acids, fatty alcohols, surfactants, silicone compounds (silicone oil or polysiloxane), solid hydrophobic particles, etc. [6,[17][18][19], might be antifoamfers, though the mechanisms of different types of defoamers are quite different. Reducing the solubility of surfactants is the most commonly used defoaming category.…”