| abstract |
There is disclosed a cyclized block copolymer having a molecular weight of from about 10,000 to about 300,000 comprised of at least two different blocks, at least one of which blocks is a cyclizable block derived from a conjugated diene monomer of the general structure <IMAGE> wherein, R1 is selected from a hydrocarbyl group containing one to twelve carbon atoms, R2 is selected from hydrogen or a hydrocarbyl group containing one to twelve carbon atoms; and at least one of which blocks is a non-cyclizable block derived from at least one member selected from the following classes of compounds: (a) polymers of conjugated diene monomers of the general structure <IMAGE> wherein: R3, R4 and R5 are the same or different and are selected from hydrogen or a hydrocarbyl group containing one to twelve carbon atoms; R6 is selected from hydrogen, a hydrocarbyl group containing one to twelve carbon atoms or a cyano group, (b) polymers of alpha -methylstyrene, styrene, alkyl or aryl substituted styrenes or halogen substituted styrenes, (c) polymethacrylonitrile, polycaprolactam, polycaprolactone or polydimethylsiloxane, said cyclized blocks constituting about 5-95 weight percent of cyclized block copolymer and said non-cyclized blocks constituting about 95-5 weight percent of cyclized block copolymer. |