ABSTRACT
Phosphazenes are ring or chain compounds consisting of alternating phosphorus–nitrogen atoms with two substituents attached to phosphorus. The chlorophosphazenes form the basis for the preparation of phosphazene fluids and lubricants. Most of the research and development of phosphazene fluids has centered on the alkoxy- and aryloxycyclophosphazenes, which are derived from the chlorotrimer and chlorotetramer. A number of references exist prior to 1980, mainly in the patent literature and in government reports, that describe the development of cyclic phosphazenes as fluids, lubricants, plasticizers, or as additives for lubricating oils and greases. Cyclic aryloxyphosphazenes are being developed as advanced lubricants for both rigid and flexible thin film magnetic media. Cyclic phosphazenes are being investigated as Halon substitutes at the New Mexico Engineering Research Institute. Phosphazenes are inherently fire resistant, and they have other properties that are necessary for high-performance applications. The main factor that has discouraged extensive development of phosphazene fluids is their high cost relative to commercial materials.
