This project investigates the synthesis, characterization, and evaluation of hospha-s-triazines of improved hydrolytic and thermal oxidative stability as tioxidants and corrosion inhibitors for polype rfluoroalkylether-based fluids capable of operation in the 330oC to 400oC temperature range. Phospha-s-triazines have been shown to be effective degradation inhibitors up to 343oC preventing interaction with metals and alloys. However, they have also been found to be susceptible to hydrolysis. Past investigations revealed that the thermal oxidative and hydrolytic stability of phospha-s-triazines is a function of the nature of the ring carbon substituents, in particular the nature of the directly attached chain segment. Currently available data indicate that thermal oxidative and hydrolytic stability of phospha-s-triazines (as well as triazines) decreases in the following order of ring carbon substituents: RfOCF(CF3)- > Rf(CF2)x- > RfOCF2CF2- (with x o 2). On the basis of this ranking it would appear that a RfOCF(CF3)2- ring carbon substituent should increase stability to above 343oC. Phase I will test this hypothesis.Perfluoropolyalkylether-based fluids, due to their low-temperature properties, low volatility, thermal oxidative stability, and high viscosity index, are practically the only candidates for any high-temperature liquid lubrication, as well as for long-term space applications. An effective degradation and corrosion inhibitor should raise upper temperature limits without sacrificing desirable low-temperature and volatility characteristics.phospha-s-triazines, perfluoropolyalkylethers, high temperature engine oils, liquid lubricants, corrosion inhibitors, degradation inhibitors
