Curable sealant composition and method for manufacturing same

A process for forming a polymer useful in a curable sealant composition comprising:

• a. initiating a living polymerization of conjugated diene monomers with a multi-functional initiator,
• b. terminating said polymerization with a tetra-substituted silicon compound of formula
• to produce a functionalized polymer, where R1, R2, R3, and R4 are independently selected from the group consisting of hydrocarbon groups, alkoxy groups and mixtures thereof, and no more than two of R1, R2, R3, and R4 may be hydrocarbon groups, and at least two of R1, R2, R3, and R4 are alkoxy groups, and
• c. hydrogenating the functionalized polymer in the presence of a catalyst system comprising a nickel carboxylate and alkylaluminum, wherein said catalyst system has a Al:Ni ratio between about 3.0 and about 4.0.