Silanes

Siliconates

A part of PCC Group with 28 years experience
Your reliable partner in the silicone field

1,1,3,5,5-PENTAPHENYL-1,3,5-TRIMETHYLTRISILOXANE

Chemical Structure

Introduction

SiSiB® PF8705 Silicone Diffusion Pump Fluid is a single component fluid designed for ultrahigh vacuum applications in the range of 10-9 to 10-10 torr (untrapped) and 10-11 torr (trapped). The low vapor pressure, low back-streaming rate and the high resistance to oxidation and radiation make this diffusion pump fluid ideal for many ultrahigh vacuum applications such as those in mass spectrometers and electron microscopes.

It has the highest phenyl content of all silicone diffusion pump fluids and the best resistance to radiation. High spontaneous ignition temperature makes this fluid ideal for use in human-rated space simulation chambers.

SiSiB® PF8705 is equal to DowCorning’s DC-705, Shin-Etsu’s HIVACF-5.

Typical Physical Properties

Product: SiSiB®PF8705
CAS No.: 3982-82-9
EINECS No. 222-222-9
Formula C33H34O2Si3
Molecular Weight: 546.88
Color and Appearance: Colorless to straw-colored fluid
Ultimate Vacuum, torr 10-9 to 10-10 untrapped
10-11 trapped
Extrapolated Vapor Pressure, 3 x 10-10 torr, 25°C
Specific Gravity at 25°C 1.09
Viscosity at 25°C 175cSt
Flash Point, open cup 243°C
Boiling Point, 0.5 torr 245°C
Typical Boiler Temperature 250-270°C
Surface Tension, dynes/cm 36.5
Heat of Vaporization, kcal/g mol 28.5/250°C

Applications

SiSiB® PF8705 Diffusion Pump Fluid can be used in a variety of applications including: Aerospace, Electronics, Metallurgy, Vacuum Coatings, and Atomic Energy etc.

Packings

SiSiB® PF8705 is supplied in 5Kg, 25Kg pail or 200Kg steel drum, for more details, please visit Packing Centre.