Polyphenyl ether
Ultra-high-vacuum fluids
Vacuum pumps are devices that remove gases from an enclosed space to greatly reduce pressure. Oil diffusion pumps in combination with a fore pump are amongst the most popular.

Polyphenyl ether

Section Title: Ultra-high-vacuum fluids
Table Section Text: Vacuum pumps are devices that remove gases from an enclosed space to greatly reduce pressure. Oil diffusion pumps in combination with a fore pump are amongst the most popular.

Fluid Property	Polyphenyl Ether SANTOVAC 5	Silicone Dow Corning	Hydrocarbon Oil Apiezon

Vapor Pressure, Torr at 25 °C	4x10−10	2x10−8	5x10−6

Molecular Weight	446	484	420

Density at 25 °C	1.20	1.07	0.87

Flash Point, °C	288	221	243

Boiling Point at 1.3 mbar, °C	295	223	220

Viscosity (cSt) at 25 °C	1000	40	135

Viscosity (cSt) at 100 °C	12.0	4.3	7.0

Surface Tension, Dynes/cm	49.9	30.5	30.5

Refractive Index at 25 °C, 589 nm	1.67	1.56	1.48

Thermal Stability	Excellent	Good	Poor

Oxidation Resistance	Excellent	Excellent	Poor-Fair

Chemical Resistance	Excellent	Good	Poor

Radiation Resistance	Excellent	Good	Fair

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