Study on polymerization conditions in homo- and copolymer syntheses of norbornene/1-hexene with nickel-based late-transition metal catalyst

Soleimannezhad, Ahmad; Mortazavi, Seyed Mohammad Mahdi; Ahmadjo, Saeid; Mansouri, Samira; Rashedi, Reza

doi:10.1007/s13726-021-00986-x

Cited by 10 publications

(19 citation statements)

References 37 publications

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“…Moreover, it seems likely that when the molar ratio of NB is well above the ENB, the addition polymerization dominates over the remaining mechanisms. It should be noted that both catalysts have been shown to perform NB polymerization through vinyl‐addition polymerization 14,44 . By contrast, the higher ENB/NB molar ratio would shift the mechanism of polymerization towards cationic polymerization with a higher contribution of transannular polymerization (Figure 8, below 1 ppm) and ROMP, indicating that the predominant polymerization mechanism is strongly influenced not only by the structure of the catalyst but also the nature of the monomer.…”

Section: Resultsmentioning

confidence: 96%

“…Binuclear and the corresponding mononuclear nickel α‐diimine catalysts were synthesized and characterized according to the methods outlined in former publications. The preparation method of the ligands, catalysts, and some general characterizations (FTIR, elemental analysis, and 1 H NMR) are reported in the supporting information; see Figures S1–S12) 12–14 . The structures of the respective catalysts are depicted in Scheme 2.…”

Section: Methodsmentioning

confidence: 99%

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Shedding light on the poly(5‐ethylidene‐2‐norbornene) microstructural differences: Skeleton rearrangements during polymerization

Omidvar,

Mansouri,

Mortazavi

et al. 2023

J of Applied Polymer Sci

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Here, an attempt is made to study one of the less noticed aspects of the polymerization of 5‐ethylidene‐2‐norbornene (ENB) by nickel α‐diimine catalysts. Therefore, several (co)polymerization runs using MMAO‐activated binuclear catalyst (BNC) and mononuclear catalyst (MNC) were undertaken. Catalyst activities as high as 561.1 and 925.0 (kgpol mol−1Ni h−1) were observed for ENB polymerization by MNC and BNC, respectively. However, the utilization of comonomer (norbornene [NB]) led to a dramatic decline in the catalyst activities, reaching low levels of 69.4 and 144.4 (kgpol mol−1Ni h−1), respectively. Structural characterization (NMR and FTIR) corroborated the occurrence of ring opening via β‐C elimination and the subsequent β‐H elimination. Additionally, tandem transannular polymerization and ring‐opening metathesis polymerization of ENB were evidenced. The findings demonstrated that the transannular polymerization prevailed during the polymerization, albeit the MNC catalyst showed a higher contribution of ring opening via β‐C elimination. Importantly, comonomer (NB) was displayed to alter the governing polymerization mechanism. According to DMTA analysis, the structures of the monomer and catalyst were found to significantly influence the polymer damping behavior and microstructure heterogeneity. That is, the NB‐ENB copolymer obtained by MNC exhibited the lowest Tg value and highest tan δ along with the diminished microstructure heterogeneity.

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Section: Resultsmentioning

confidence: 96%

Section: Methodsmentioning

confidence: 99%

Shedding light on the poly(5‐ethylidene‐2‐norbornene) microstructural differences: Skeleton rearrangements during polymerization

Omidvar,

Mansouri,

Mortazavi

et al. 2023

J of Applied Polymer Sci

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“…High density and linear low‐density polyethylene, HDPE, and LLDPE constitute the highest share of synthetic polymers market in the world 10,11 . These polymers are commercially produced mostly by heterogeneous Ziegler Natta catalysts 4,12,13 .…”

Section: Introductionmentioning

confidence: 99%

“…[7][8][9] High density and linear low-density polyethylene, HDPE, and LLDPE constitute the highest share of synthetic polymers market in the world. 10,11 These polymers are commercially produced mostly by heterogeneous Ziegler Natta catalysts. 4,12,13 These catalysts are mainly composed of support (MgCl 2 , Mg(OEt) 2 , and silica) and TiCl 4 as active center, and occasionally electron donor to control isotacticity in polypropylene.…”

Section: Introductionmentioning

confidence: 99%

Effect of adduct synthesis parameters on the ethylene polymerization kinetics of Ziegler Natta catalysts

Nouri-Ahangarani

Bahri‐Laleh

Abedini

et al. 2023

J of Applied Polymer Sci

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Here, it is aimed to clarify the structure-performance relationship in MgCl 2 based Ziegler Natta catalysts toward ethylene polymerizations. In this regard, 11 different adduct precursors were prepared through industrially appreciated melt quenching method employing various: (i) reaction times for dissolving magnesium chloride inside ethanol; (ii) ethanol/MgCl 2 molar ratios in the feed; (iii) heating rates during thermal dealcoholation; (iv) N 2 flows during thermal dealcoholation and (v) alcohol content after thermal dealcoholation. Among the studied parameters, heating rate and N 2 flow during thermal dealcoholation have the most pronounced effect on the porosity and particle size of the resulted adducts. Related Ziegler Natta catalysts were subsequently employed in ethylene polymerizations. According to the kinetic curves, catalyst productivity and form of kinetic curve (as decay or build-up type) can be precisely tailored by proper choosing of the mentioned variables during adduct synthesis. Microstructure analysis of the prepared polyethylenes reveals that alcohol content in the final adduct has the most significant effect on the H 2 response, in terms of molar mass and its distribution, of the related Ziegler Natta catalysts. The overall results help polyethylene producers in choosing proper reaction conditions during adduct synthesis for the production of different polymer grades, when productivity or H 2 response is targeted.

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“…However, only five metallocene catalysts have been kinetically studied in the literature, partly because there are no efficient methods or rapid kinetic models for obtaining necessary information, such as active site counts. [7][8][9][10][11][12][13] The basic steps of metallocene-catalyzed olefin polymerization are well known. Clark R.…”

Section: Introductionmentioning

confidence: 99%

Ansa-metallocene Catalyst based on 3-phenyl and 4-methyl Substituted: Catalyst Evaluation in Conjugated and Non-conjugated Diene Polymerization

ALI,

Nadeem,

Naveed

et al. 2023

Preprint

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In this contribution, we describe the kinetics associated with the rac-Me2Si[2-Me-4-Ph-Ind]2ZrCl2 (Cat-1)/borate/TIBA catalyzed copolymerization of E/dienes (isoprene (IP), butadiene (BD), 5-ethylidene-2-norbornene (ENB), 4-vinylcyclohexene (VCH) and vinyl norbornene (VNB)), and E/diene/1-hexene (1H) terpolymerization by using thiophenecarbonyl chloride (TPCC) that was used in Ziegler-Natta (Z-N) and metallocene-catalyzed polyethylene (PE) and polypropylene (PP) and E/P polymerizations. In both types of polymerizations, a higher amount of dienes was incorporated when VNB (2.70 mole %) and VCH (1.56 mole %) were added as comonomer, but IP and BD were incorporated with the moderated rate (0.6-1.1 mole %) with higher activities (3.45x106gm/mmolMt·h). The active center [Zr]/[C*] fraction is higher (61%) than previously reported PE polymerizations, especially in the case of E/IP, E/BD and E/IP/1H but lower than E/P (87%) copolymerization. Significantly, IP and BD activated the inactive catalytic sites that were dormant in the PE. The propagation rate constant (kpE) with IP was higher (kp564 Lmol-1s-1), while kpE with VNB (kp379 Lmol-1s-1) and VCH (kp304 Lmol-1s-1), which were lower than PE. This difference is built because of the diffusion barrier in the system. Compared to E/diene copolymers, kpE values in E/diene/1H terpolymerizations for IP, VCH, and VNB are higher and stable except ENB and determine that 1H prevents the insertion of dienes and reduces the crystalline properties resultant moderate kpE. Even though the E/BD copolymers decreased butadiene content of over 2 mol% resulted in better crystalline characteristics, lower diffusion barriers, and a higher kpE value. In concept, IP and BD are linear and readily available for coordination. While VCH, ENB and VNB are cyclic and bulky, metallocene in contact ion pairs cannot accept ENB, VNB, and VCH for coordination and subsequently act as dormant in the polymerization.

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Study on polymerization conditions in homo- and copolymer syntheses of norbornene/1-hexene with nickel-based late-transition metal catalyst

Cited by 10 publications

References 37 publications

Shedding light on the poly(5‐ethylidene‐2‐norbornene) microstructural differences: Skeleton rearrangements during polymerization

Shedding light on the poly(5‐ethylidene‐2‐norbornene) microstructural differences: Skeleton rearrangements during polymerization

Effect of adduct synthesis parameters on the ethylene polymerization kinetics of Ziegler Natta catalysts

Ansa-metallocene Catalyst based on 3-phenyl and 4-methyl Substituted: Catalyst Evaluation in Conjugated and Non-conjugated Diene Polymerization

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