The properties of three copolymers with medium Mooney viscosity value of butadiene and isoprene polymerized by rare earth catalyst(Ln-BIR),as well as their blends with natural rubber(NR) at blending ratio of 50/50 were studied.

• 研究了中门尼粘度稀土催化丁二烯－ 异戊二烯共聚橡胶（ Ln － B I R） 及其与 N R 以50/ 50（ 质量比）共混的硫化胶性能。