Interplay of reversible chain transfer andcomonomer incorporation reactions in coordinationcopolymerization of ethylene/1–hexene
محل انتشار: فصلنامه پلی اولفین ها، دوره: 7، شماره: 1
سال انتشار: 1398
نوع سند: مقاله ژورنالی
زبان: انگلیسی
مشاهده: 750
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شناسه ملی سند علمی:
JR_POJ-7-1_001
تاریخ نمایه سازی: 29 اسفند 1398
چکیده مقاله:
Coordinative chain transfer polymerization (CCTP) has opened a new path for the development of novelproducts like olefin block copolymers and chain-end functional polyolefins. However, conflicting resultsare frequently reported on the catalyst performance including activity and comonomer selectivity under CCTPconditions. Here we have selected two catalysts including rac-ethylenebis(1-η5-indenyl)zirconocene and bis(imino)pyridine iron, with drastically different comonomer affinities. The effect of diethyl zinc as the chain transfer agent(CTA) on their individual performances is evaluated at different 1–hexene concentrations, in copolymerization withethylene. Combined thermal fractionation and GPC results confirm that not all chains experience the reversibletransfer reaction. Nevertheless, the metallocene catalyst shows twice activity and about 30% lower comonomerincorporation in the presence of CTA. Conversely, the late transition metal catalyst demonstrates lower activityand remains comonomer irresponsive. It could be concluded that, in addition to establishing a reversible transferreaction, CTA affects the nature of active centers. This finding can help designing olefin copolymers with a moredefined chemical composition based on CCTP reaction. Polyolefins J (2020) 7: 1-11
کلیدواژه ها:
Coordination polymerization ، reversible chain transfer reaction ، chemical composition ، microstructure
نویسندگان
Ali Ebrahimi
Department of Polymer Engineering and Color Technology, Amirkabir University of Technology, Tehran, Iran
Saeid Ahmadjo
Engineering Department, Catalyst Group, Iran Polymer and Petrochemical Institute, Tehran, Iran
Mohsen Mohammadi
Department of Polymer Engineering, Faculty of Engineering, Qom University of Technology, Qom, Iran
Mohammad Mahdi Mortazavi
Institute of Physical Chemistry, Johannes Gutenberg-Universität Mainz, Duesbergweg ۱۰-۱۴, D-۵۵۱۲۸ Mainz, Germany