Use as bearing material

Polymers and composites can be used as bearing materials in a wide range of applications. They are particularly appropriate for bearings in which a film of lubricant cannot be maintained between the working surfaces at all times. 

Old and Nicholas [110] studied a range of Pb/Sn alloys reinforced with carbon fiber for possible use as bearing materials and published a review [111] on the prospects of metal... 

Zinc MMCs have been developed [739] for potential use as bearing materials. Zinc has a density of 7.14 g/cm. An MMC with a ZA-27 zinc alloy matrix was cast with 1, 3, and 5 wt % graphite particles ranging in sizes from 100 to 150 pm. Zinc alloys are known to have excellent wear and bearing characteristics [740]. Gravimetric corrosion tests were conducted at 23°C in ... 

Molded polyimides are widely used as bearing materials because of their high temperature and compressive capabilities, chemical resistance, and natural lubricity. These bearings are found in jet engines, appliances, and office equipment. Polyimides are also... 

Alternatively, the enamine portion may be located in the Aralkyl chain. For instance, piperidines bearing a 7-chloro substituent yielded quinolizidines 263 through a conjugate addition of the nitrogen atom to acetylenic sulfones followed by an intramolecular alkylation (Scheme 55) <2000JOC4543>. Other cyclizations that are summarized below used as starting materials piperidine derivatives obtained by similar conjugate additions to vinyl sulfones (see Section 12.01.9.3.6). 

Triazoles bearing a C-amino substituent have been used as starting materials for several syntheses of biologically important com-... 

Better and Davidsohn (23) reported that the susceptibility of proteins in oilseed presscaFe and solvent-extracted meal was strongly affected by heat treatment. Working with peanut and coconut presscake, they demonstrated that the stronger the heat treatment, the higher are the concentrations of pepsin required to make peptization more complete. This is an important fact to bear in mind when oilseed press or extraction residues are being used as raw materials for production of industrial protein. 

Wood. Although lignum vitae and oil-impregnated maple and oak are useful up to 70°C, they have largely been replaced as bearing materials by porous metals, plastics, and mbber. Typical application of wood bearings are with water and other low viscosity fluids at relatively low speeds in pumps, conveyors, hydraulic turbines, food and chemical processing, and ship propeller shafts (27). 

Boutevin, B., Hervaud, Y., Mouledous, G., and Vera, R., Synthesis of polyols bearing phosphonate groups. Part 2. Epoxides used as starting materials. Phosphorus, Sulfur Silicon Relat. Elem., 161, 9,... 

The alkaloid physostigmin (1) and its analogues bearing pyrrolo[2.3-b]pyrrolidine structural units have attracted attention because of their activity as cholinesterase inhibitors. A short synthesis of compound 2 possessing a pyrrolopyrrolidine skeleton includes the following reactions, in which 4-hydroxycoumarine (X, cf problem 76) is used as starting material ... 

---