ABSTRACT
Tribology is loosely translated from Greek as “the science of rubbing.” In a lighthearted view, the “tri” can be considered to be the three areas of friction, wear, and lubrication. Much work has been historically performed in the sliding of metallic systems, both dry and lubricated. From this great body of work, virtually all of the current “laws” of friction have evolved. Unfortunately, the subtopic of polymer-onmetal or polymer-on-polymer sliding systems violate most of the so-called laws, thus invalidating them relative to polymers. However, examination of the popular misconceptions (typically those taught in high school or undergraduate physics) is instructive for an understanding of polymeric systems. This chapter concentrates on dry and nonliquid lubricated polymer-on-metal or polymer-on-polymer sliding. The only lubrication discussed is self-lubrication or dry-lubricant films
Examples of polymers in tribological applications are the following:
1. Self-lubricated guides for slide assemblies 2. Gears 3. Housings for low-speed, lightly loaded shafts 4. Pumps 5. Conveyer chains 6. Fluid meters 7. Seals 8. Tires and wheels 9. Belts
Obviously, the potential application list is more extensive. Polymers are used in tribological applications for many of the same reasons as they are used in structural applications. In many instances, polymers perform a dual function as both a structural and a tribological material. An example of dual functionality is self-lubricated polymers that are injection molded into structural housings for low-speed, lightly loaded rotating shafts. Concerns such as weight, cost, and manufacturability are some of the same issues with the use of polymers and polymeric composites for sliding applications as in structural applications.
