Copolymerization of ethylene and 1-hexene using (n-BuCp)2ZrCl2 catalyst activated by the cross-linked MAO supported cocatalyst

Yoon, Keun Byoung; Lee, Dong Hoon; Noh, Seok Kyun

doi:10.1007/bf03218516

Cited by 8 publications

(4 citation statements)

References 23 publications

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“…[39,40] When the metallocene is immobilized over a carrier, this phenomenon is enhanced since the diffusion rate of ethylene through the highly crystalline polymer formed around the catalyst sites is slow until sufficient polymer has been formed to start particle fragmentation. [38,39,[41][42][43] When an a-olefin comonomer is added to the reactor, forming LLDPE chains, the diffusion rate of ethylene in the polymer increases significantly, leading to higher apparent polymerization rates and extended particle fragmentation. Interestingly, the 1-hexene concentration at which the catalytic activity achieves its maximum increases steadily with pore diameter in the order: 0.066 mol L À1 (11.3 nm), 0.318 mol L À1 (22.7 nm) and 0.612 mol L À1 (28.5 nm).…”

Section: Resultsmentioning

confidence: 99%

Ethylene/1‐Hexene Copolymers Produced with MAO/(nBuCp)₂ZrCl₂ Supported on SBA‐15 Materials with Different Pore Sizes

Paredes¹,

Grieken²,

Carrero³

et al. 2011

Macro Chemistry & Physics

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The influence of the support architecture (structure and pore size) on the activity of MAO/(nBuCp)2ZrCl2 heterogeneous catalysts in the polymerization of ethylene and 1‐hexene is studied through the characterization of the polymers' microstructure. SBA‐15 silica‐based mesostructured materials are synthesized with different pore sizes and compared with commercial silica. All SBA‐15 supported catalysts lead to higher catalytic activities than amorphous silica and give rise to ethylene/1‐hexene copolymers with bimodal CCD, which suggests that the carrier structure plays an important role not only in the global rate of the process but also in the copolymer composition. The structures and pore sizes of the support show a marked influence on the polymer CCD shape. magnified image

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Section: Resultsmentioning

confidence: 99%

Ethylene/1‐Hexene Copolymers Produced with MAO/(nBuCp)₂ZrCl₂ Supported on SBA‐15 Materials with Different Pore Sizes

Paredes¹,

Grieken²,

Carrero³

et al. 2011

Macro Chemistry & Physics

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“…Many authors have claimed solubility enhancement of copolymer chains and subsequent improvement in mass transfer processes as the key factor in Ziegler-Natta and supported metallocene catalysts [2,7,15,22,24,25,26,31,34,35,36,37,38,39,40,41,42,43], however although an easier diffusion of the monomer through less crystalline phases may contribute to a rate enhancement, no satisfactory correlation has been found with crystallinity degree or copolymer solubility [44].…”

Section: Introductionmentioning

confidence: 99%

A New Insight into the Comonomer Effect through NMR Analysis in Metallocene Catalysed Propene–co–1-Nonene Copolymers

García‐Peñas

Barranco‐García

et al. 2019

Polymers

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The “comonomer effect” is an intriguing kinetic phenomenon in olefin copolymerization that still remains without a detailed explanation. It typically relates to the rate of enhancement undergone in ethylene and propene catalytic polymerization just by adding small fractions of an alpha-olefin. The difficulty lies in the fact that changes caused by the presence of the comonomer in reaction parameters are so conspicuous that it is really difficult to pin down which of them is the primary cause and which ones are side factors with marginal contribution to the phenomenon. Recent investigations point to the modification of the catalyst active sites as the main driving factor. In this work, the comonomer effect in the metallocene copolymerization of propene and 1-nonene is analysed and correlated to the comonomer role in the termination of the chain-growing process. The associated termination mechanisms involved furnish most of chain-free active sites, in which the selective interaction of the comonomer was proposed to trigger the insertion of monomers. A thorough characterisation of chain-end groups by means of the 1H NMR technique allows for detailing of specific transfer processes, ascribed to comonomer insertions, as well as evidencing the influence of the growing chain’s microstructure over the different termination processes available.

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“…MAO will be used as the cocatalyst. We have chosen ( n BuCp) 2 ZrCl 2 because it is one of the preferred metallocenes for ethylene polymerization 28–36. It is reasonably cheaper than most of the metallocene analogues.…”

Section: Introductionmentioning

confidence: 99%

Supported (ⁿBuCp)₂ZrCl₂ Catalysts: Effects of Selected Lewis Acid Organotin Silica Surface Modifiers on Ethylene Polymerization

Akhtar

Atiqullah

Moman

et al. 2008

Macro Reaction Engineering

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This study investigated the effects of several organotin silica surface modifiers on the ethylene polymerization performance of (nBuCp)2ZrCl2‐based supported catalysts in which MAO and metallocene were sequentially loaded. Each organotin compound acted as a spacer, increasing the catalyst activity. However, the catalyst activity and $\overline M _{\rm w}$ of the resulting polyethylenes varied as follows: Activity and fractional Sn+ charge: nBuSn(OH)2Cl > MeSnCl3 > nBuSnCl3 > Reference catalyst; and, $\overline M _{\rm w}$: Reference catalyst > nBuSnCl3 > MeSnCl3 > nBuSn(OH)2Cl. The above catalyst activity rating was explained considering the influence of the Lewis acidity, that is, the fractional Sn+ charge of the organotin modifiers on the generation, concentration, and electron density at the active [(nBuCp)2ZrMe]+ cation. All the catalysts showed fairly stable kinetic profiles and produced narrow molecular weight distribution resins; 2.8 ≤ PDI ≤ 3.

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Copolymerization of ethylene and 1-hexene using (n-BuCp)2ZrCl2 catalyst activated by the cross-linked MAO supported cocatalyst

Cited by 8 publications

References 23 publications

Ethylene/1‐Hexene Copolymers Produced with MAO/(nBuCp)₂ZrCl₂ Supported on SBA‐15 Materials with Different Pore Sizes

Ethylene/1‐Hexene Copolymers Produced with MAO/(nBuCp)₂ZrCl₂ Supported on SBA‐15 Materials with Different Pore Sizes

A New Insight into the Comonomer Effect through NMR Analysis in Metallocene Catalysed Propene–co–1-Nonene Copolymers

Supported (ⁿBuCp)₂ZrCl₂ Catalysts: Effects of Selected Lewis Acid Organotin Silica Surface Modifiers on Ethylene Polymerization

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Copolymerization of ethylene and 1-hexene using (n-BuCp)2ZrCl2 catalyst activated by the cross-linked MAO supported cocatalyst

Cited by 8 publications

References 23 publications

Ethylene/1‐Hexene Copolymers Produced with MAO/(nBuCp)2ZrCl2 Supported on SBA‐15 Materials with Different Pore Sizes

Ethylene/1‐Hexene Copolymers Produced with MAO/(nBuCp)2ZrCl2 Supported on SBA‐15 Materials with Different Pore Sizes

A New Insight into the Comonomer Effect through NMR Analysis in Metallocene Catalysed Propene–co–1-Nonene Copolymers

Supported (nBuCp)2ZrCl2 Catalysts: Effects of Selected Lewis Acid Organotin Silica Surface Modifiers on Ethylene Polymerization

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Ethylene/1‐Hexene Copolymers Produced with MAO/(nBuCp)₂ZrCl₂ Supported on SBA‐15 Materials with Different Pore Sizes

Ethylene/1‐Hexene Copolymers Produced with MAO/(nBuCp)₂ZrCl₂ Supported on SBA‐15 Materials with Different Pore Sizes

Supported (ⁿBuCp)₂ZrCl₂ Catalysts: Effects of Selected Lewis Acid Organotin Silica Surface Modifiers on Ethylene Polymerization