Synthesis and characterization of ring polybutadienes

It has been shown that butadiene initiated with potassium naphthalene in the mixture THF‐ n ‐hexane polymerizes conveniently rapidly. The active center is sufficiently stable below 0°C to produce narrow molecular weight linear polybutadiene. The two‐ended living polymer has also served to prepare ring polybutadienes. The analysis of the ring polymers by a high‐resolution set of SEC columns proved superior to the conventional method for the determination of the linear content in rings and in synthetic mixtures of rings and linear polymers. Dilute solution characterization of the linear and ring polymers shows that g r ′ = [η]/ r [η] l is less than 0.66 in a good solvent.