| 摘要 |
A polymer comprising repeat units derived from 1,3-butadiene and a substituted butadiene of formula I or II is disclosed. R is hydrogen, an alkyl group, aryl group, or a fused cyclic group. At least 95 percent by weight of the repeat units have a cis-1,4 microstructure. Also, a rubber composition and a pneumatic tire comprising such a polymer is disclosed. |
