Liquid methylpolysiloxane mixtures, or silicone oils, exhibit unusually small changes in viscosity with temperature. Their viscosities at 100'F. are only about two and one-half times those at 21.0'F.) while the corresponding factor for a petroleum oil of viscosity index 100 is about eight. This behavior of silicone oils suggested investigation of the relations between the viscous properties and the vapor pressure-temperature characteristics of those smaller ...
