Synthesis and characterization of polybutadiene and poly(ethylene-1-butene) combs

A series of polybutadiene "combs" with polydispersities less than 1.2 have been synthesized using anionic polymerization techniques. Control was exerted over the average number and length of branches but not on their placement along the polybutadiene backbone. Hydrogenation of the materials resulted in the formation of the corresponding poly(ethylene-co-butene) combs. The effects of branching on the solution properties of the polybutadiene combs have been examined. As predicted using the Berry-Orofino model, the "shrinking factor" g ' decreases with increasing branch length. The effect of branching on the Zimm-Stockmayer parameter, g, has also been investigated.