Performance characteristics and applications of oligomethylphenylsiloxanes

All oligomethylphenylsiloxanes are transparent colourless or yellowish liquids. The most viscous oligomers range from light yellow to light brown. 

In all these spheres the temperature performance characteristics of oligomethylphenylsiloxanes have the greatest importance. The maximum allowable performance temperatures for oligomethylphenylsiloxanes range from -20- -100 flo200-350°C depending on their composition, degree of polymerisation and presence of phenyl substituents in molecules. 

Oligomethylphenylsiloxanes are characterised by improved thermal stability, low glass transition temperatures, low vapour pressure and compati- 

Liquids FM-5, FM-6, FM-5,6 AP are used as dispersion media in low-temperature oils and lubricants cooling heat carriers. They are also used in light-loaded high-speed ball bearings in freon refrigerating systems. 

Diffusion oils for high-vacuum pumps (ultimate vacuum up to 13.3 pPa) are the most valuable and high-quality materials based on oli-gomethylphenylsiloxanes. Their vacuum properties cannot be rivalled by any other classes of chemical compounds. First and foremost, one should take into account that high-vacuum liquids for diffusion pumps should be resistant to oxidation at high temperatures. 

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