Conjugated dienes useful in the tapered block copolymers preferably have from about 4 to about 5 carbon atoms, for example, butadiene, isoprene, cis-1,3-pentadiene, trans-1,3-pentadiene, copolymers of two or more dienes such as butadiene and isoprene and block copolymers of two or more such dienes such as butadiene and isoprene.