DISSOLUTION OF PERFLUOROALKYL OLIGOMERS IN LUBRICATING OIL FOR ENHANCING WEAR-RESISTANCE AND FUEL-ECONOMY

Perfluorobutyl-1,1,2-tri-H-1-hexene and perfluoroalkyl methacrylate ha ve been solubilized in lubricating oil by single-step free radically g rafting onto poly(ethylene-co-propylene). Perfluoroalkyl-1,1,2,2-tetra -H-ethanol and perfluoropolyether carboxylic acid were solubilized by condensing with poly[(ethylene- co-propylene)-g-glycidyl methacrylate] , generating the corresponding perfluoroalkyl ether or ester, respecti vely. Solubilization of 1,1,2,2 tetra-H-ethanol was also achieved by c ondensing with poly[(ethylene-co-propylene)-g-2isocyanoethyl methacryl ate] to the corresponding perfluoroalkyl urethane. Scar diameter reduc tions ranged from 9.4 to 58% using perfluoro-modified graft copolymers as determined using the Four Ball Wear Test, although optimum reducti ons were obtained using perfluoroalkyl urethane-modified graft copolym ers. Moreover, a semiquantitative correlation of scar reductions and t hermal instability was determined. Sequence VI engine testing of perfl uoroalkyl urethane graft copolymers containing pendant perfiuoroalkyl chain lengths of 8.2 and 7.2 had an Equivalent Fuel Economy Index of 4 .33 and 4.27, respectively. (C) 1994 John Wiley & Sons, Inc.