Block copolymers of polybutadiene and polydimethylsi fo-cane

poly (Bdb--DMS)

were prepared by sequential addition of butadiene and octomethylcyclotetrasi fo-cane(D4)

using potassium α-methylnaphthalenide as initiator. Results show thatfinal conversion of D4 varies significantly with its initial concentration

but not changewith the molecular weight and living chain end concentration of polybutadieneblocks; and also not with the polymerization temperature within 10-40oC. Studieswere also made on the ring-openingkinetics of D4 during block copolymerization initiate by polybutadiene living chains. It is shown that the kinetic procedure is similar to that initiated by small molecular anionic initiator. And the apparent rate constant for D4 propagation is found to be 10 kg/mol·h in THF at 30℃

and the corresponding apparent activation energy to be 28.3kJ/mol.