Patent ID: 7396887

Claim:
A process comprising: a. forming a living prepolymer high vinyl initiator with a vinyl content greater than about 45% using a vinyl modifier, b. adding a R 1 R 2 R 3 aluminum or R 1 R 2 R 3 boron compound, 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, wherein said polymer product has an overall vinyl content of less than 35%, and where R 1 , R 2 , and R 3 are selected from the group consisting of C1-C12 alkyl, C2-C12 alkene, C2-C12 alkyne, phenyl, alkyl-substituted phenyl and may all be identical or may all be separately selected but cannot be H.