Glycol Synthetic PAG Oil Explained The terms polyalkylene glycol and polyglycol are used interchangeably. These fluids can be manufactured to be either water soluble or water insoluble (oil soluble). The most common are the water-soluble fluids, and thus they can have some very different properties. Polyglycols are moderately polar, which gives them moderate film strength properties. They have a very high viscosity index (180 to 280) and good low and high temperature abilities. They burn off cleanly, leaving no residue, and have been used as a carrier oil for solid lubricants for high-temperature chain lubrication. Some versions are food grade and biodegradable. They are used as compressor oils in rotary screw and reciprocating units, worm gear oils, fire-resistant lubricants, metal-working fluids and as brake fluids. Water-soluble polyglycols are not compatible with mineral oils and therefore must be handled and disposed of separately. They should not be mixed with mineral oils. The result is a gelatinous, gooey mess. Although they are excellent lubricants, they can pose a logistic problem in plants. They can also have some negative effects on paints and seals, and are very expensive. Water-insoluble (oil-soluble) polyglycols are likely to become more common and are used as heat transfer fluids, high-temperature bearing oils and in screw-type refrigeration compressors. For centuries, lubricants have been utilized as a way to reduce friction and wear on moving parts. In 2005, 40 million tons of lubricants were produced. While natural mineral oil-based fluids represent the majority of the market demand, many technological advances in equipment and machinery would not be possible without the benefits offered by improvements in synthetic lubricants, which currently make up only two percent of the market. While polyalphaolefins (PAOs) fill some of these needs, a growing number of applications are demand.