Provided herein are polymerization processes and polymer compositions including reactor blends formed by such polymerization processes. The polymerization processes include copolymerization using two metallocene catalyst systems: the first catalyst system capable of producing polymers having 60% or more vinyl terminations, the second catalyst system capable of producing high molecular weight polymers, preferably incorporating at least some of the polymers produced by the first catalyst system into the high molecular weight polymers. The reactor blends formed thereby therefore include first and second copolymer components, which may differ in monomer content and weight-average molecular weight (Mw). Furthermore, the reactor blends may exhibit advantageous rheological properties, at least some of which are consistent with long-chain branching. Preferred reactor blends comprise ethylene-propylene-diene (EPDM) terpolymers.
本文提供的是聚合工艺和聚合物组合物,包括由此类聚合工艺形成的反应器混合物。聚合工艺包括使用两种茂
金属催化剂体系进行共聚合:第一种催化剂体系能够生产具有 60% 或更多
乙烯基末端的聚合物,第二种催化剂体系能够生产高分子量聚合物,最好将第一种催化剂体系生产的至少部分聚合物并入高分子量聚合物中。因此,由此形成的反应器混合物包括第一和第二共聚物组分,它们的单体含量和重量平均分子量(Mw)可能不同。此外,反应器混合物还可表现出良好的流变特性,其中至少有一些与长链支化相一致。首选的反应器混合物包括
乙烯-
丙烯-二烯(EP
DM)三元共聚物。