Amorphous to high crystalline PE made by mono and dinuclear Fe-based catalysts

Khoshsefat, Mostafa; Dechal, Abbas; Ahmadjo, Saeid; Mortazavi, Seyed Mohammad Mahdi; Zohuri, Gholamhossein; Soares, João B. P.

doi:10.1016/j.eurpolymj.2019.07.042

Cited by 29 publications

(22 citation statements)

References 48 publications

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“…Previous achievements have approved the efficiency of both MAO and MMAO cocatalysts in activating the iron or cobalt precatalysts for ethylene polymerization [ 40 , 41 , 42 , 43 ]. Therefore, the title metal complexes have been screened for their catalytic performances towards ethylene polymerization with the assistance of either methyluminoxane (MAO) or modified methyluminoxane (MMAO).…”

Section: Resultsmentioning

confidence: 99%

6-Arylimino-2-(2-(1-phenylethyl)naphthalen-1-yl)-iminopyridylmetal (Fe and Co) Complexes as Highly Active Precatalysts for Ethylene Polymerization: Influence of Metal and/or Substituents on the Active, Thermostable Performance of Their Complexes and Resultant Polyethylenes

et al. 2020

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A series of 6-arylimino-2-(2-(1-phenylethyl)naphthalen-1-yl)iminopyridines and their iron(II) and cobalt(II) complexes (Fe1–Fe5, Co1–Co5) were synthesized and routinely characterized as were Co3 and Co5 complexes, studied by single crystal X-ray crystallography, which individually displayed a distorted square pyramidal or trigonal bipyramid around a cobalt center. Upon treatment with either methyluminoxane (MAO) or modified methyluminoxane (MMAO), all complexes displayed high activities regarding ethylene polymerization even at an elevated temperature, enhancing the thermostability of the active species. In general, iron precatalysts showed higher activities than their cobalt analogs; for example, 10.9 × 106 g(PE) mol−1 (Co) h−1 by Co4 and 17.0 × 106 g(PE) mol−1 (Fe) h−1 by Fe4. Bulkier substituents are favored for increasing the molecular weights of the resultant polyethylenes, such as 25.6 kg mol−1 obtained by Co3 and 297 kg mol−1 obtained by Fe3. A narrow polydispersity of polyethylenes was observed by iron precatalysts activated by MMAO, indicating a single-site active species formed.

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Section: Resultsmentioning

confidence: 99%

6-Arylimino-2-(2-(1-phenylethyl)naphthalen-1-yl)-iminopyridylmetal (Fe and Co) Complexes as Highly Active Precatalysts for Ethylene Polymerization: Influence of Metal and/or Substituents on the Active, Thermostable Performance of Their Complexes and Resultant Polyethylenes

et al. 2020

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“…This interest is due to their outstanding behaviour in polymerization of olefins for production of linear to hyperbranched and low to high molecular weight (M w ) polyolefins, introduction of polar and even bio-sourced comonomers into the backbone of polyolefins. [24][25][26][27][28][29][30][31][32] Based on this, there are many papers on the study of these catalysts behaviour. Moreover, they kept their position in the mentioned systems for production of olefinic copolymers.…”

Section: Introductionmentioning

confidence: 99%

“…These complexes are bearing methyl and iso-propyl on the side aryl rings showing optimum bulkiness (in respect of activity and CTE) which used in the presence and absence of DEZ for polymerization of ethylene. [5,17,28,29,42] These catalysts were compared with further mono-and homodinuclear structures (Scheme 2). The effect of CSA on the behaviour of each catalyst and molecular, thermal and mechanical properties of the polymer obtained were studied, comprehensively.…”

Section: Introductionmentioning

confidence: 99%

“…Although the catalysts based on rare‐earth metals have shown good results in these kinds of polymerizations but transition metals especially the late ones are much more interesting and attractive. This interest is due to their outstanding behaviour in polymerization of olefins for production of linear to hyperbranched and low to high molecular weight (M w ) polyolefins, introduction of polar and even bio‐sourced comonomers into the backbone of polyolefins [24–32] . Based on this, there are many papers on the study of these catalysts behaviour.…”

Section: Introductionmentioning

confidence: 99%

“…Herein, we designed a series of heterodinuclear and mononuclear catalyst structures (Scheme 1; current work) based on our previous reports and literatures. These complexes are bearing methyl and iso‐ propyl on the side aryl rings showing optimum bulkiness (in respect of activity and CTE) which used in the presence and absence of DEZ for polymerization of ethylene [5,17,28,29,42] . These catalysts were compared with further mono‐ and homodinuclear structures (Scheme 2).…”

Section: Introductionmentioning

confidence: 99%

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Zn‐assisted cooperative effect for copolymers made by heterodinuclear Fe−Ni catalyst

et al. 2020

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Mononuclear Fe and Ni based catalysts (M 1 and M 2) in the form of single and dual catalytic systems were employed in the presence and absence of diethyl zinc (DEZ) for polymerization of ethylene. In addition, corresponding homo-(M 3 and M 4) and heterodinuclear catalysts (M 7) along with the mononuclear analogues (M 5 and M 6) were used to explore the effect of adjacency of second metal center on the chain transfer efficiency. DEZ had stronger influence on the behavior of mono-and dinuclear Fe-based structures and corresponding thermal and microstructural properties of the PE samples than Ni complexes. A mechanism was proposed for M 5 as the vinylterminated polymer chains increased in the presence of DEZ. More interestingly, M 7 not only showed a cooperative effect for production of a random copolymer containing short and long chain branches but also at low and high concentration of DEZ, a blocky copolymer was obtained through CCTP and CSP. These results were confirmed by 13 C NMR, DMTA, SSA and CEF.

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Microstructural study on MMA/1‐hexene copolymers made by mononuclear and dinuclear α‐diimine nickel (II) catalysts

Bagherabadi

Zohuri

Ramezanian

et al. 2020

Applied Organom Chemis

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Homogenous catalytic homopolymerization and copolymerization of 1-hexene (H) with methyl methacrylate (MMA) were carried out in presence of two different types of mononuclear (MNC1 and MNC2) and dinuclear Ni-based catalysts (BNC1 and BNC2). Modified methylaluminoxane was used as cocatalyst due to good reactivity in MMA/H copolymerization. Among the structures, BNC1 showed the highest catalyst activity (6.9 × 10 4 g P. mol −1 Ni. h −1). Although M w of the copolymer made by BNC1 was higher than its mononuclear, molecular weight distribution was broader. The optimum molar ratios for mononuclear and dinuclear were obtained at [Al]/[Ni] = 1,000:1 and [Al]/[Ni] = 1,500:1, respectively. Surprisingly, introduction of MMA (up to [MMA]/[H] = 50:50 molar ratio) into the polymerization solution increased the activity of all catalysts. 1 H NMR analysis study revealed that increasing of MMA in the feed composition raised incorporation of the comonomer into the obtained copolymers. The result was consistent on the calculated reactivity ratio of monomers, using Kelen-Tudos method. In addition, BNC1 (at [MMA]/[H] = 70:30 molar ratio) demonstrated more incorporation of MMA to the main copolymer chain (95.2% mol). On the other side, study on tacticity of the PMMA sample was investigated that showed a distribution of stereoregularity in the order of atactic > > syndiotatic > isotactic (53.2 > 26.7 > 20.1). In addition, for copolymers made by BNC1, an unusual pattern was observed as lower concentration of MMA in the feed (i.e., 30%) led to high isotactic blocks of MMA. The highest branching density of the polymer, however, was obtained by BNC1 (217/1000C) and the lowest by BNC2 (80/1000C). Higher extent of the polar comonomer (MMA) in the copolymer backbone led to increasing of T g for the copolymer samples (from 74.4 to 98.9 C). The structural properties of the obtained copolymers were investigated using both Fourier transform infrared spectroscopy and Raman spectroscopies, as well.

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Amorphous to high crystalline PE made by mono and dinuclear Fe-based catalysts

Cited by 29 publications

References 48 publications

6-Arylimino-2-(2-(1-phenylethyl)naphthalen-1-yl)-iminopyridylmetal (Fe and Co) Complexes as Highly Active Precatalysts for Ethylene Polymerization: Influence of Metal and/or Substituents on the Active, Thermostable Performance of Their Complexes and Resultant Polyethylenes

6-Arylimino-2-(2-(1-phenylethyl)naphthalen-1-yl)-iminopyridylmetal (Fe and Co) Complexes as Highly Active Precatalysts for Ethylene Polymerization: Influence of Metal and/or Substituents on the Active, Thermostable Performance of Their Complexes and Resultant Polyethylenes

Zn‐assisted cooperative effect for copolymers made by heterodinuclear Fe−Ni catalyst

Microstructural study on MMA/1‐hexene copolymers made by mononuclear and dinuclear α‐diimine nickel (II) catalysts

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