Coupled styrenic block copolymers and process for preparing same

摘要

Disclosed is an improvement to a process for preparing coupled styrenic block copolymers wherein adding from about 0.01 to about 1.5 equivalents of a metal alkyl compound per equivalent of living polymer chain ends to the cement, during or after polymerization, improves coupling efficiencies. The resultant radial styrenic block copolymers have reduced amounts of 5+ arm oligomers which can be very desirable is certain applications, such as the modification of bitumen.