Tandem coordinative chain transfer polymerization for long chain branched Polyethylene: The role of chain displacement

Dashti, Arezoo; Ahmadi, Mostafa; Haddadi‐Asl, Vahid; Ahmadjo, Saeid; Mortazavi, Seyed Mohammad Mahdi

doi:10.1016/j.eurpolymj.2023.112008

Cited by 5 publications

(9 citation statements)

References 81 publications

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“…Proposed polymerization mechanism was further promoted by DFT simulations. 82 However, the chain-walking mechanism of the α-diimine Ni complex, which is responsible for the creation of the branching structure, hampers the formation of linear crystallizable sequences resulting in completely amorphous material. Thus, α-diimine Ni complex was replaced by more industrial metallocene complex, rac-EtInd 2 ZrCl 2 (5, Figure 3) that provides a semicrystalline branched polyethylene with longer linear sequences, which can be investigated by thermal analysis.…”

Section: Discussionmentioning

confidence: 99%

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Coordinative Chain Transfer and Chain Shuttling Polymerization

Mundil,

Bravo,

Merle

et al. 2023

Chem. Rev.

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Coordinative chain transfer polymerization, CCTP, is a degenerative chain transfer polymerization process that has a wide range of applications. It allows a highly controlled synthesis of polyolefins, stereoregular polydienes, and stereoregular polystyrene, including (stereo)block as well as statistical copolymers thereof. It also shows a green character by allowing catalyst economy during the synthesis of such polymers. CCTP notably allows the end functionalization of both the commodity and stereoregular specialty polymers aforementionned, control of the composition of statistical copolymers without adjusting the feed, and quantitative formation of 1-alkenes from ethene. A one-pot one-step synthesis of the original multiblock microstructures and architectures by chain shuttling polymerization (CSP) is also an asset of CCTP. This methodology takes advantage of the simultaneous presence of two catalysts of different selectivity toward comonomers that produce blocks of different composition/microstructure, while still allowing the chain transfer. This affords the production of highly performant functional polymers, such as thermoplastic elastomers and adhesives, among others. This approach has been extended to cyclic esters' and ethers' ring-opening polymerization, providing new types of multiblock microstructure. The present Review provides the state of the art in the field with a focus on the last 10 years.

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Section: Discussionmentioning

confidence: 99%

“…The formation of highly branched PEs (branch-on-branch structure) was revealed by 13 C NMR and rheological measurements. Proposed polymerization mechanism was further promoted by DFT simulations …”

Section: Coordinative Chain Transfer Polymerizationmentioning

confidence: 99%

Coordinative Chain Transfer and Chain Shuttling Polymerization

Mundil,

Bravo,

Merle

et al. 2023

Chem. Rev.

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“…[4][5][6][7][8][9][10] Among them, nickel compounds were initially considered "poisons" for olefin polymerization due to the discovery of the famous "Nickel effect" by Ziegler and his colleagues. 11 Now, many nickel catalysts have been found to produce highmolecular-weight polyethylene, including α-diimine (Scheme 1a, I), [12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31] pyridine-imine (Scheme 1a, II), [32][33][34] salicylaldehyde imine (Scheme 1a, III), [35][36][37][38][39] α-imino ketone (Scheme 1a, IV), 40,41 aniline naphthoquinone Jinke Shou and Pei Li contributed equally to this work.…”

Section: Introductionmentioning

confidence: 99%

Steric and temperature effects in unsymmetrical α‐diimine nickel‐catalyzed ethylene and 1‐octene polymerization

Shou,

Li,

Tian

et al. 2024

Applied Organom Chemis

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In this contribution, a series of unsymmetric α‐diimine nickel complexes are synthesized. One side of these nickel complexes is the 2,4‐dimethyl‐6‐diphenylmethylaniline unit, and the steric effects are tuned by changing another aniline unit. These nickel complexes have high catalytic activities in ethylene (>106 g mol−1 h−1) and 1‐octene (104–105 g mol−1 h−1) polymerization, generating high‐molecular‐weight polyolefins (Mn > 104 g mol−1) with tunable branching densities (59–91/1000C). Steric effects and polymerization temperature can significantly affect the catalytic performance of the catalyst. Most importantly, catalysts with different steric hindrances have different temperature sensitivity. In general, catalysts with larger steric hindrances are more sensitive to temperature. This may be due to the fact that the rotation of some chemical bonds is blocked at low temperatures due to the larger volume of the substituents, resulting in more significant temperature sensitivity.

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“…An extension of such CCTP reactions is a Ni-based displacement/polymerization tandem process where the reinsertion of the so-formed olefin into the polyethylene backbone allows the formation of branched polyethylene (see Ahmadi et al, Scheme ). ,, …”

Section: Introductionmentioning

confidence: 99%

“…CCTP of conjugated dienes mainly relies on early transition metals or rare earth metals . If CCTP studies using nickel catalysts were reported for ethylene over the past decade, – to the best of our knowledge, the ability of Ni(II) allyl catalysts for CCTP of conjugated dienes has not been explored so far. Nickel complexes such as Ni(COD) 2 or Ni(acac) 2 (acac = acetylacetonate) were in turn used as displacement catalysts in the course of ethylene CCTP, notably by Kempe et al, allowing the selective formation of 1-alkene by β-hydride elimination (Scheme ).…”

Section: Introductionmentioning

confidence: 99%

Coordinative Chain Transfer Polymerization of Butadiene Using Nickel(II) Allyl Systems: A Straightforward Route to Branched Polybutadiene

Bravo,

Merle,

Sauthier

et al. 2023

Macromolecules

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Nickel allyl complexes are catalysts for the 1,4-regioselective polymerization of butadiene (BD). Coordinative chain transfer polymerization (CCTP) was not yet assessed by using these systems. We report in this work the polymerization of butadiene in the presence of π-allyl Nickel(II) trifluoroacetate (TFA) and MgnBuEt or AlEt3 as chain transfer agent (CTA) case studies. The reaction follows a first-order kinetic versus the monomer. Chain transfer is evidenced in the presence of CTAs, together with the formation of polybutadiene bearing a conjugated diene moiety. This allows one-pot access to branched polybutadiene by reinsertion of the chains. The branching is quantitatively analyzed by 13C NMR after hydrogenation of the polybutadiene, and its impact on the thermal properties of the hydrogenated samples is assessed, in particular for low degrees of branching that cannot be quantitatively determined. A full description of the catalytic cycle is tentatively provided. If similar tandem processes were described in the literature in the course of the polymerization of ethylene, it is, as far as we know, the only system reported so far for a conjugated diene leading to branched polybutadiene thus extending the range of application of CCTP processes.

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Tandem coordinative chain transfer polymerization for long chain branched Polyethylene: The role of chain displacement

Cited by 5 publications

References 81 publications

Coordinative Chain Transfer and Chain Shuttling Polymerization

Coordinative Chain Transfer and Chain Shuttling Polymerization

Steric and temperature effects in unsymmetrical α‐diimine nickel‐catalyzed ethylene and 1‐octene polymerization

Coordinative Chain Transfer Polymerization of Butadiene Using Nickel(II) Allyl Systems: A Straightforward Route to Branched Polybutadiene

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