Facile, Efficient Copolymerization of Ethylene with Norbornene-Containing Dienes Promoted by Single Site Non-Metallocene Oxovanadium(V) Catalytic System

Abstract

Non-metallocene oxovanadium(V) complexes bearing either [ONNO]-type amine pyridine bis(phenolate) ligands or [ONN]-type amine pyridine phenolate ligands were employed as efficient catalysts to copolymerize ethylene with several unsymmetrical norbornene-containing dienes, such as 5-vinyl-2-norbornene (VNB), 5-ethylidene-2-norbornene (ENB) or dicyclopentadiene (DCPD), producing copolymers with high comonomer incorporations (VNB: 33.0 mol %; ENB: 30.4 mol %; DCPD: 31.6 mol %, respectively) and high molecular weight (VNB: 86.4 kDa; ENB: 256 kDa; DCPD: 86.4 kDa, respectively). The enchainment of the dienes was proven to be exclusive of vinyl-addition via the C=C double bond of the norbornene ring while the other double bond was retained near the backbone without crosslinking. During the copolymerization of ethylene with ENB, a positive 'comonomer effect' was observed. The catalytic activities of the catalysts as well as the molecular weights and comonomer incorporations of the resultant copolymers could be tuned within a wide range by varying the structures of the catalysts and copolymerization conditions. The [ONN]-type oxovanadium(V) complexes showed higher catalytic activities than those of [ONNO]-type oxovanadium(V) complexes, irrespective of the structure of the dienes. In addition, the dominant chain transfer pathway of the non-metallocene oxovanadium(V) catalytic system promoted copolymerization was proven to be transfer to aluminum compounds.

5‐Ethylidene‐2‐norbornene Polymerization by α‐Diimine Nickel Catalyst: A Revealing Insight into the Pivotal Function of Binuclear and Mononuclear Catalyst Structure in Tailoring Polymer Architecture

“…[ 18 ] Concerning the ethylene copolymerization with 5‐ethylidene‐2‐norbornene, the vanadium catalyst has been demonstrated to be highly active, enjoying the capacity to yield a polymer with a high molecular weight and a higher degree of comonomer insertion. [ 19 ] It was particularly understood that the application of Pd N ‐heterocyclic carbene complexes as a catalyst has been adjusted to provide a soluble high molecular weight poly 5‐ethylidene‐2‐norbornene (PENB). [ 20 ] Chemical modification via grafting different functional groups to polymer chains provides this category of cyclic polyolefin with atractive properties, such as improved transparency, greater adhesion as well as enhanced compatibility with other polymers.…”

Bis-(salicylaldehyde-benzhydrylimino)nickel complexes with different electron groups: crystal structure and their catalytic properties toward (co)polymerization of norbornene and 1-hexene

“…There are three polymerization methods: ringopening metathesis polymerization (ROMP), [4][5][6][7][8] cationic or radical polymerization, 9 and vinyl-addition polymerization. [10][11][12][13][14][15][16][17] The polymers obtained by the vinyl addition polymerization method had high thermal stability, high optical permeability, a low dielectric constant, low moisture absorption and other excellent properties and were widely used in micro electronics and optics. However, the further development of norbornene is hampered by its poor bond properties, low solubility and poor mechanical properties.…”