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Copolymer Structure and Performance Consequences of High‐Impact Ethylene–Propylene Copolymers Based on a Ziegler–Natta Catalyst with Novel Internal Donor
Author(s) -
Pellecchia Roberta,
Shutov Pavel,
Wang Jingbo,
Gahleitner Markus
Publication year - 2020
Publication title -
macromolecular reaction engineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.37
H-Index - 32
eISSN - 1862-8338
pISSN - 1862-832X
DOI - 10.1002/mren.202000022
Subject(s) - copolymer , materials science , polypropylene , polymerization , tacticity , elastomer , polymer , ziegler–natta catalyst , natta , chemical engineering , polymer chemistry , catalysis , ethylene , phase (matter) , composite material , organic chemistry , chemistry , engineering
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 13 C‐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%.