Abstract: A heat curable silicone rubber composition, having improved resistance to engine coolants and oils, including long-life coolants and synthetic motor oils, comprises: (A) 100 parts by weight of an organosiloxane polymer base comprising an organosiloxane polymer containing at least 2 silicon-bonded alkenyl groups in each molecule and 1 to 65 weight percent reinforcing silica filler, (B) curing component sufficient to cure the composition when heated, and (C) an effective amount of at least one metal salt additive selected from the group consisting of monobasic alkali metal phosphates, alkali metal oxalates, alkali metal tartrates, alkali metal tetraborates, alkali metal phthalates, alkali metal citrates; dibasic metal phosphates where the metal is selected from the group consisting of sodium, potassium, calcium and magnesium; metal acetates, where the metal is selected from the group consisting of sodium, potassium, calcium, magnesium; metal sulfates where the metal is selected from the group consisting of s

Abstract: The present invention is stereoregular poly{methyl(3,3,3-trifluoropropyl)siloxane} polymers and copolymers and methods for their making. The process involves reacting isomers of 1,3,5-trimethyl-1,3,5-tris(3',3',3'-trifluoropropyl)cyclotrisiloxane in the presence of an aprotic polar promoter and a lithium compound. The lithium compound initiates ring opening and polymerization of the isomers without effecting the steric arrangement of the isomers. Elastomers prepared by cross-linking polymers of the present invention can have sufficient cis 3,3,3-trifluoropropyl substitution to allow the elastomers to strain crystallize and provide reinforcement to the elastomers at typical use temperatures.