Silica-supported metallocenes: effect of the preparation procedure on the morphology of polyethylene particles

Lin, Chun-Ping; Sheu, C. S.

doi:10.1002/1521-3927(20001001)21:15<1058::aid-marc1058>3.3.co;2-b

Cited by 5 publications

(6 citation statements)

References 4 publications

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“…The silica image predominantly shows round and oval particles with little particle size variation. Likewise, the polyethylene resin grew as particles of regular round and oval shapes, similar to the silica support, in accordance with published results 17. Fig 2 presents the light microscope image of the polyethylene obtained, which shows that the polyethylene particle has a compact texture and globular shape 16…”

Section: Resultssupporting

confidence: 86%

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Supported zirconocene catalyst for preventing reactor fouling in ethylene polymerization

Entezami

Moghadam

2005

Polymer International

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The commercial interest of metallocene complexes for olefin polymerization has led to additional efforts to prepare suitable metallocene complexes efficiently and economically. Ethylene polymerization was carried out with a series of heterogeneous catalysts which were prepared in various Zr/silica ratios by immobilization of Ind 2 ZrCl 2 preactivated with methylaluminoxane (MAO) on silica. This method to form the catalyst system resulted in a polymerization catalyst with reduced fouling tendencies and improved reactor operability. Polymerization of ethylene was conducted in Buchi reactors in a slurry phase under mild pressure. Some of the physical properties of the obtained polymers were also determined.

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Section: Resultssupporting

confidence: 86%

“…The Ind 2 ZrCl 2 and MAO have to be premixed to form an activated zirconocene type suitable for anchoring onto silica. In methylated metallocene ([(C 9 H 7 ) 2 ZrCH 3 ] + [MAO] − ), MAO binds more strongly to the silica than to the zirconocene and the active species is Ind 2 ZrMe + electrostatically bound to the MAO‐grafted silica 17…”

Section: Resultsmentioning

confidence: 99%

Supported zirconocene catalyst for preventing reactor fouling in ethylene polymerization

Entezami

Moghadam

2005

Polymer International

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“…For example, in one of the rare studies on the nascent morphology of PE made using a metallocene, it has been shown that fibrils are formed in a manner similar to that presented above 64. In another recent study, morphologies similar to those seen in Figure 9 were observed 65. On the one hand, metallocene and Ziegler‐Natta catalysts have chemically different active sites, so produce different polymer chain.…”

Section: The Nascent Morphology Of Polyolefin Particles and Polymersmentioning

confidence: 80%

Particle Growth During the Polymerisation of Olefins on Supported Catalysts, 1 – Nascent Polymer Structures

McKenna

Martino

Weickert

et al. 2009

Macro Reaction Engineering

119

128

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It is shown that the relationship between the catalyst/polymer structure, process conditions and final product properties needs to be addressed in more detail. From an industrial point of view, the interest starts from the need to control the growth of the catalyst/polymer particle during the polymerisation process. This first part of a two-part review discusses the different factors that can influence the physical properties of the nascent polymer, and how these can impact the evolution of particle morphology. 40

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“…Heterogeneous catalysts are much easier to store, transport and add into a reactor [15]. Besides the physical aspects, the chemical advantages of heterogenized systems are improved stabilization of the active metal centers during polymerization [4], control of the polymer particle-morphology [16,17], and control of the polymerization activity during the process by tuning the fragmentation pattern of the catalyst support particles [14,17,18].…”

Section: Introductionmentioning

confidence: 99%

Fragmentable Heterogeneous Cocatalysts for the Metallocene-Catalyzed Polymerization of Olefins, II [1]. Preparation, Characterization and Testing of the Cocatalysts and Microscopic Evaluation of the Polyethylene

Schumann

Widmaier

Lange

et al. 2005

Zeitschrift Für Naturforschung B

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Surface modified silica were reacted with different aluminiumalkyls AlR2R’ (R = Me, Et, i-Bu, R’ = H, Me, Et, i-Bu), oligomeric methylaluminoxane (MAO) and combinations of both, to yield heterogeneous cocatalysts. These cocatalyts were employed to polymerize ethylene using zirconocene dichloride as the catalyst. The polymerization activity profiles have been recorded and compared with the information gained from the scanning electron microscopy (SEM) images of the polymers. The fragmentation of the heterogeneous cocatalyts upon polymerization has been demonstrated. The degree of fragmentation and the polymerization activity depend on the preparation of the silica supports and on the preparation of the heterogeneous cocatalysts using these supports. The most reactive, fragmentable heterogeneous cocatalysts show polymerization activities slightly higher than MAO in homogeneous solution and almost 1.5 times higher than commercially available MAO on silica (=MAO on Sylopol).

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Silica-supported metallocenes: effect of the preparation procedure on the morphology of polyethylene particles

Cited by 5 publications

References 4 publications

Supported zirconocene catalyst for preventing reactor fouling in ethylene polymerization

Supported zirconocene catalyst for preventing reactor fouling in ethylene polymerization

Particle Growth During the Polymerisation of Olefins on Supported Catalysts, 1 – Nascent Polymer Structures

Fragmentable Heterogeneous Cocatalysts for the Metallocene-Catalyzed Polymerization of Olefins, II [1]. Preparation, Characterization and Testing of the Cocatalysts and Microscopic Evaluation of the Polyethylene

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