US Patent 7396887 Insitu removal of chelator from anionic polymerization reactions

A process for producing polymers having at least one high vinyl end segment is provided. The process comprises: (a) forming a living prepolymer high vinyl initiator with a vinyl content greater than about 45% using a vinyl modifier, (b) adding a R1R2R3aluminum or R1R2R3boron compound to nullify the effect of the vinyl modifier, and (c) initiating polymerization of diene monomers using said living prepolymer high vinyl initiator so as to form a polymer product with at least one high vinyl end segment, where R1, R2, and R3 are selected from the group consisting of C1-C12 alkyl, C2-C12 alkene, C2-C12 alkyne, phenyl, and alkyl-substituted phenyl, and may all be identical or may all be separately selected but cannot be H. The polymers having at least one high vinyl end segment may be coupled to produce a polymer having a high vinyl end segment on all ends.