On the topology of highly branched polyethylenes prepared by amine−imine nickel and palladium complexes: the effect of ortho‐aryl substituents. Issue 7 (3rd May 2018)

• Record Type: Journal Article
• Authors: Mundil, Robert; Hermanová, Soňa; Peschel, Martin; Lederer, Albena; Merna, Jan
• Is Part Of: Polymer international. Volume 67:Issue 7(2018)
• Page Start: 946
• Page End: 956
• Publication Date: 2018-05-03
• Subjects: amine−imine complexes -- chain‐walking mechanism -- living polymerization -- topology -- branching -- polyolefins; Plastics -- Periodicals; Polymers -- Periodicals; Polymerization -- Periodicals; 547.7
• DOI: 10.1002/pi.5593
• Languages: English
• ISSNs: 0959-8103

Abstract

ABSTRACT: Series of nickel and palladium complexes bearing amine−imine ligands in various ortho ‐aryl and backbone positions were prepared and investigated in ethene polymerization. Ethene polymerization initiated by symmetrically ortho ‐substituted nickel and palladium amine−imine catalysts is controlled. Mono‐substitution in the ortho ‐aryl positions of nickel complexes is not as efficient in protecting centers from chain transfer as di‐substitution. Both the central metal and the size of the ortho ‐aryl substituent have a significant effect on the polyethylene (PE) topology. Based on detailed characterization by high temperature SEC‐IR‐η, SEC with multi‐angle laser light scattering and 13 C NMR data, PEs prepared by nickel amine−imine complexes have a linear rather than dendritic topology. In contrast, palladium amine−imine complexes with small ortho ‐aryl substituents at low ethene pressure were shown for the first time to form dendritic PEs with topology comparable to PEs formed by α‐diimine palladium catalyst. © 2018 Society of Chemical Industry Abstract : Dendritic polyethylene (PE) can be formed by palladium amine−imine catalysts bearing small ortho ‐aryl substituents at high ethene dilution. Nickel analogs provide PEs with similar branching densities but rather linear topology.