Self-lubricating capacity

It has been noted that many polymeric systems have the capacity to induce what is called self lubrication. As a consequence it has not been a major focus of research activity, compared to metallic and ceramic systems, to study the lubrication of polymers per se, but more often to consider the infiuence of environmental sensitivity. For convenience the two are dealt with together here. We may also note that polymers are often included into polar and apolar solvents to modify the rheological behaviour as is conunon practice in the formulation of viscosity improvers and the development of drag reducing agents. These processes may have implications in rationalisation of environmental sensitivity. 

Just like other lamellar solids, boric acid is also self-lubricating. Its lubrication mechanism is similar to that of the other solid lubricants. It can be manufactured as very fine nanopowders. Because of their light weight, these nano-powders can easily be dispersed in oils and used as colloidal anti-friction and -wear additives. Tribological studies have confirmed that they have very high capacity to reduce friction and wear. TOF-SIMS and XPS studies... 

There are many applications of PTFE that use one or more of its specific properties self-lubrication, chemical inertia, thermostability, and anti-adhesive capacity. It also finds applications in mechanical engineering, chemical and textile industries as well as in electrical engineering. 

Various other soft materials without the layer—lattice stmcture are used as soHd lubricants (58), eg, basic white lead or lead carbonate [598-63-0] used in thread compounds, lime [1305-78-8] as a carrier in wire drawing, talc [14807-96-6] and bentonite [1302-78-9] as fillers for grease for cable pulling, and zinc oxide [1314-13-2] in high load capacity greases. Graphite fluoride is effective as a thin-film lubricant up to 400°C and is especially useful with a suitable binder such as polyimide varnish (59). Boric acid has been shown to have promise as a self-replenishing soHd composite (60). 

The thermal analysis of plain journal bearings is a complex matter and this may be particularly true for bearings of the self-contained type. The lubricant feed temperature Is generally not known for self-contained bearings and is mainly a function of the capacity of the bearing to dissipate the heat generated within the lubricant film. A further difficulty arises from the fact that the thermal environment may be different for specific applications of a particular design. 

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