Strain-crystallizing poly(methyl(3,3,3-trifluoropropyl)-siloxane) elastomers and methods for making

摘要

Strain-crystallizing poly{methyl(3,3,3-trifluoropropyl) siloxane} elastomers and methods for their making. The process comprises the cross- linking of cis stereoregular polymers prepared by reacting isomers of 1,3, 5-trimethyl-1,3,5-tris(3',3',3'-trifluoropropyl) cyclotrisiloxane, where at least 30 percent of the isomers are of cis configuration, in the presence of an aprotic polar promoter and a lithium compound. The lithium compound initiates ring opening and polymerization of the isomers without affecting the steric arrangement of the leomars. Elastomers prepared by cross-linking these cis stereoregular polymers 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.