Catalyst development for advanced isotactic polypropylene copolymer grades cannot be considered without parallel work on the polymerization process, especially when multi‐phase high‐impact ethylene‐propylene copolymers (also called heterophasic copolymers, HECOs) of complex composition are considered. Using a Ziegler–Natta type catalyst produced in an emulsion process and using citraconate ester as internal donor, a series of such high‐impact copolymers is first produced in a bench‐scale reactor. At this stage, the content of ethylene‐propylene copolymer (EPC) phase is varied in a wide range for understanding the catalyst performance as well as the resulting structure‐property relations, using three‐stage polymerization to emulate multiple reactors. Selected compositions are subsequently scaled up to a multi‐reactor pilot plant, demonstrating composition effects on mechanical performance. Both stages are accompanied by structural investigations using ¹³C‐NMR spectroscopy and atomic force microscopy. The novel catalyst is found to be capable of synthesizing HECOs in a wide range of elastomer (EPC) content, achieving free‐flowing polymer powders up to an elastomer content as expressed by the xylene cold soluble fraction of 37 wt%.

中文翻译：

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齐格勒-纳塔催化剂与新型内部给体的高影响力乙烯-丙烯共聚物的共聚物结构和性能后果

如果没有在聚合过程中并行进行的工作，就无法考虑开发高级等规聚丙烯共聚物的催化剂，尤其是考虑到复杂组成的多相高抗冲乙烯丙烯共聚物（也称为多相共聚物，HECO）时。使用乳液法生产的Ziegler-Natta型催化剂，并使用柠檬酸酯作为内部供体，首先在台式反应器中生产了一系列此类高抗冲共聚物。在此阶段，乙烯-丙烯共聚物（EPC）相的含量在很大范围内变化，以了解催化剂性能以及由此产生的结构-性质关系，并使用三阶段聚合模拟多个反应器。随后将选定的成分放大到多反应器中试工厂，证明了成分对机械性能的影响。这两个阶段都伴随着使用¹³ C-NMR光谱和原子力显微镜。发现这种新型催化剂能够合成多种弹性体（EPC）含量的HECO，实现高达37％的二甲苯冷可溶物含量所表示的弹性体含量的自由流动聚合物粉末。