Video Microscopy for Fast Screening of Polymerization Catalysts

Abboud, Mohammed; Kallio, Kalle; Reichert, Karl‐Heinz

doi:10.1002/ceat.200401947

Cited by 18 publications

(26 citation statements)

References 8 publications

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“…23,24 Relative volume growth factors (volumes of the polymer particles divided by the original volumes) of individual catalyst particles were determined in order to study the activity distribution and growth behavior of single catalyst particles. More than 100 particles were analyzed for particle growth measurements,.…”

Section: Video Microscopy (Vm)mentioning

confidence: 99%

“…22 The type of catalyst support affects the overall activity and activity profile of heterogeneous catalysts and determines the type of catalyst fragmentation. [23][24][25] MgCl 2 , as a support for polymerization catalysts, fragments much more extensively at low polymer yields than does as an SiO 2 support. MgCl 2 as a support is believed to consist of agglomerations of small crystalline subparticles that are more loosely aggregated than they would with SiO 2 .…”

Section: Introductionmentioning

confidence: 99%

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Study of the morphology and kinetics of novel Ziegler–Natta catalysts for propylene polymerization

Abboud

Denifl

Reichert

2005

J of Applied Polymer Sci

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ABSTRACT:The morphological and kinetic characteristics of novel Ziegler-Natta catalysts were studied. Catalysts were prepared by Borealis Polymers Oy using a new synthesis technique (emulsion technology). Video microscopy was used to study the growth of single catalyst particles during polymerization in the gas and liquid phases. The distribution of single particle activity was very narrow in the catalyst without external support and was rather broad in the the silica-supported catalyst. Video microscopy of molten polymer particles allowed observation of the process and degree of fragmentation of the catalyst particles. A correlation between the activation period during the initial stage of polymerization and catalyst fragmentation was found. Fragmentation was faster and more uniform with the catalyst without external support than with the silica-supported catalyst. Scanning electron microscopy provided information on morphology evolution and shape replication of the catalyst particles. With the catalyst without external support, good shape replication was observed, and compact and spherical particles were formed. With the silica-supported catalyst, shape replication was poor, and nonspherical porous polymer particle were formed. Modeling of the kinetics of propylene polymerization was done using a simple threestep reaction scheme neglecting mass and heat transport effects.

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Section: Video Microscopy (Vm)mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Study of the morphology and kinetics of novel Ziegler–Natta catalysts for propylene polymerization

Abboud

Denifl

Reichert

2005

J of Applied Polymer Sci

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“…[11] Fink et al [12] further improved the video microscopy method, allowing the online observation of a large number of catalyst particles during ethylene polymerization allowing parallel single particle investigation. Weickert et al [13] recently employed video microscopy for optical and infrared investigations of growing particles.…”

Section: Introductionmentioning

confidence: 99%

Video Microscopy for the Investigation of Gas Phase Copolymerization

Fink

2005

Macro Materials & Eng

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Summary: Video microscopy as a tool for investigating olefin gas phase copolymerization is presented for the first time in this paper. The central theme of this work is the study of the comonomer effect shown by an unbridged metallocene catalyst supported on silica. By using video microscopy, it is possible to observe the increase in catalytic activity in terms of particle growth as well as monomer consumption. The observation that a more pronounced induction period in the particle growth profile is shown with increasing propylene concentration led us to investigate the copolymers obtained at different polymerization times using 13C NMR analysis and single particle energy dispersive X‐ray (EDX mapping). This allowed us to adapt the “polymer growth and particle expansion model” to the copolymerization. Besides physical causes for the comonomer effect, we wanted to determine whether the catalyst structure plays an important role in the comonomer effect. To this end we investigated two metallocenes bearing the same long bridging unit but differing in the ligand bound to the zirconium center. One metallocene bears a cyclopentadienyl ring, while the other bears an indenyl group. From a close analysis of the 13C NMR, it is clear that both catalysts insert ethylene more easily then propylene, probably due to the long bridging unit that results in a narrower aperture angle of the ligand. In addition to this, the indenyl ligand does not allow the formation of propylene blocks even at high propylene concentration.

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“…Hence the video microscopic analysis is not only a tool in the screening of supported catalysts [228] but also a useful instrument for the assignment of a given (industrial) catalyst system to the appropriate kinetic profile and the mathematical model. Finally, it is possible to explain certain aspects of crystalline homopolymer growth versus amorphous copolymer growth and the comonomer effect [225,226].…”

Section: Video Microscopymentioning

confidence: 99%

Polymerization on Molecular Catalysts

Fink

2008

Handbook of Heterogeneous Catalysis

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Video Microscopy for Fast Screening of Polymerization Catalysts

Cited by 18 publications

References 8 publications

Study of the morphology and kinetics of novel Ziegler–Natta catalysts for propylene polymerization

Study of the morphology and kinetics of novel Ziegler–Natta catalysts for propylene polymerization

Video Microscopy for the Investigation of Gas Phase Copolymerization

Polymerization on Molecular Catalysts

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