Process for production of alkadiene-based polymer of increased vinyl content

The process of claim 2 wherein the structure modifier is provided in an amount from about 10 ppm to about 1000 ppm based on total weight of alkadiene and diluent.

In the process of producing a homopolymer of butadiene or isoprene of increased vinyl content by polymerizing butadiene or isoprene under polymerization conditions in the presence of a hydrocarbon reaction diluent, an alkyllithium polymerization initiator and a structure modifier, the improvement of using as the structure modifier a compound of the formula ##STR7## wherein R is an alkylene bridging group of up to 10 carbon atoms inclusive with from 2 to 4 carbon atoms inclusive in the bridge, R' is alkyl of up to 10 carbon atoms inclusive, and R" is hydrogen or hydrocarbyl of up to 10 carbon atoms inclusive.

The process of producing a copolymer of conjugated alkadiene and vinylaromatic hydrocarbon of increased vinyl content under polymerization conditions in the presence of a hydrocarbon reaction diluent, an alkyllithium polymerization initiator and a structure modifier, the improvement of using as structure modifier a compound of the formula ##STR8## wherein R is an alkylene bridging group of up to 10 carbon atom inclusive with from 2 to 4 carbon atoms inclusive in the bridge, R' is alkyl of up to 10 carbon atoms inclusive, and R" is hydrogen or hydrocarbyl of up to 10 carbon atoms inclusive.