ABSTRACT
In this chapter, anhydrous ¨uids will be discussed Ÿrst, followed by water-based ¨uids, where certain of the anhydrous ¨uid types are emulsiŸed or dissolved in the water phase. Historically, many lubricants were biobased, consisting of or containing natural fats and oils and their derivatives, but with the increasing availability of petroleum-based ¨uids (mineral oils) by the latter half of the 1800s, petroleum and products derived from it have become the primary source of lubricating ¨uids. In more recent decades, a variety of synthetic products have found application in the marketplace. Two texts the reader may consult for more detail on these products are Shubkin [1] and Mang and Dresel [2]. More recently again, there has been renewed interest in biobased products as a result of the environmental beneŸts associated with the use of products from renewable sources.
