Triple Tandem Catalyst Mixtures for the Synthesis of Polyethylenes with Varying Structures

Komon, Zachary J. A.; Diamond, Gary M.; Leclerc, Margarete K.; Murphy, Vince; Okazaki, Miho; Bazan, Guillermo C.

doi:10.1021/ja0283551

Cited by 137 publications

(71 citation statements)

References 26 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…[311] HTTs have been developed to screen for mixtures of three catalysts for ethylene polymerization. [312] Unusual catalysts mixtures were discovered, which produce branched polyethylene, which is not obtainable with single or two-component catalysts. The properties of the new polymers were dependent on the catalyst ratios.…”

Section: Polymerization Catalysts For Polyolefinsmentioning

confidence: 99%

“…[312] Pasch et al have shown how size-exclusion chromatography (SEC) and high-pressure liquid chromatography (HPLC) can be accelerated for HTS applications to provide relative molecular weight distributions of a variety of polymers (PEG, PEO, epoxy resins) in 2-6 minutes per sample. [314] In the HT development of pressure-sensitive adhesives, Mehrabi and co-workers used the absorbance of visible light in conjunction with a dye for the determination of film thicknesses.…”

Section: Angewandte Chemiementioning

confidence: 99%

See 1 more Smart Citation

Combinatorial and High‐Throughput Materials Science

2007

View full text Add to dashboard Cite

There is increasing acceptance of high-throughput technologies for the discovery, development, and optimization of materials and catalysts in industry. Over the years, the relative synchronous development of technologies for parallel synthesis and characterization has been accompanied by developments in associated software and information technologies. This Review aims to provide a comprehensive overview on the state of the art of the field by selected examples. Technologies developed to aid research on complex materials are covered as well as databases, design of experiment, data-mining technologies, modeling approaches, and evolutionary strategies for development. Different methods for parallel synthesis provide single sample libraries, gradient libraries for electronic or optical materials, similar to polymers and catalysts, and products produced through formulation strategies. Many examples illustrate the variety of isolated solutions and document the barely recognized variety of new methods for the synthesis and analysis of almost any material. The Review ends with a summary of success stories and statements on still-present problems and future tasks.

show abstract

Section: Polymerization Catalysts For Polyolefinsmentioning

confidence: 99%

Section: Angewandte Chemiementioning

confidence: 99%

Combinatorial and High‐Throughput Materials Science

2007

View full text Add to dashboard Cite

show abstract

“…Homogeneous ''tandem catalysis'' has also received attention as an alternative approach to branched polyethylenes. Here, a single-site catalytic center produces ␣-olefin oligomers, which are subsequently incorporated, via an intermolecular process, into highmolecular-weight polyethylene by a second, different single-site catalytic center present in the same reaction medium and using the same ethylene feed (26)(27)(28). It should be evident that, at typical polymerization concentrations, these intermolecular tandem processes are inherently inefficient.…”

Section: Binuclear Structures and Macromolecular Branch Formation In mentioning

confidence: 99%

Nuclearity and cooperativity effects in binuclear catalysts and cocatalysts for olefin polymerization

Marks

2006

Proc. Natl. Acad. Sci. U.S.A.

225

109

View full text Add to dashboard Cite

A series of bimetallic organo-group 4 ''constrained geometry'' catalysts and binuclear bisborane and bisborate cocatalysts have been synthesized to probe catalyst center-catalyst center cooperativity effects on olefin enchainment in homogenous olefin polymerization and copolymerization processes. Significant nuclearity effects are found versus mononuclear controls, and the effect can be correlated with metal-metal approach distances and ion pairing effects. Novel polymer structures can be obtained by using such binuclear catalyst͞cocatalyst systems.catalysis ͉ polymer ͉ polyolefin E nzymes achieve superior reactivity and selectivity, in part, by their efficacy in creating high local reagent concentrations and special, conformationally advantageous active site-substrate proximities and interactions (1-4). In this regard, the possibility of unique and more efficient abiotic catalytic transformations based on cooperative effects between adjacent active centers in multinuclear transition metal complexes is currently of great interest. Within the context of the rapidly advancing and technologically significant field of homogeneous single-site olefin polymerization catalysis (5-10), the conjecture that cooperative effects involving two or more metal centers in close proximity might achieve more efficient chain propagation and͞or novel polymer architectures motivated the research that is the subject of this contribution. Single-Site Olefin Polymerization ProcessesOne of the most exciting developments in the areas of catalysis, organometallic chemistry, and polymer science in recent years has been the intense development of new polymerization technologies based on well defined single-site metallocene and coordination complex olefin polymerization catalysts (5-10). The active catalytic species is typically generated by combining a transition-metal organometallic precursor with an activator or cocatalyst. The resulting electrophilic͞coordinatively unsaturated, strongly ionpaired species then undergoes rapid olefin enchainment. In optimum cases (e.g., group 4 metal and cyclopentadienyl-type ligand), catalysts with truly exceptional productivities and selectivities for high-molecular-weight polyolefins are produced. Constrained Geometry Catalysts: Testbeds for Multinuclear Cooperativity EffectsGroup 4 ''constrained geometry'' catalysts (CGCs) (A; Fig. 1) are well known single-site polymerization agents (16, 17) that produce unusual branched, hence far more processable, polyethylenes with high productivity and selectivity. One of the key features of these catalysts is the coordinatively open nature of the active site, which allows rapid enchainment of sterically encumbered olefin comonomers into the polyethylene backbone. Under certain conditions, these catalysts yield vinyl-terminated, chain-transferred macromonomers (a macromolecule that acts as a monomer) that diffuse away and then undergo competitive reinsertion into a growing polymer chain to produce macromolecules with long chain branching (Fig. 19, which is published ...

show abstract

“…[302] [311] HTT wurden auch für die Testung von Mischungen aus drei Katalysatoren zur Ethylenpolymerisation entwickelt. [312] Dabei wurden Katalysatormischungen entdeckt, die verzweigtes Polyethylen erzeugen, das mit einheitlichen oder binären Katalysatormischungen nicht erzeugt werden kann. Die Anteile der einzelnen Katalysatoren bestimmen dabei die Eigenschaften der neuen Polymere.…”

Section: Magnetische Materialienunclassified

“…[313] Die Bestimmung der Molekulargewichtsverteilung von Polymeren, die mit konventionellen Messverfahren mehrere Stunden dauert, kann mit kurzen GPC-Säulen und Messrobotik in wenigen Minuten durchgeführt wurden. [312] Pasch et al konnten zeigen, dass Größenausschlusschromatogra-phie (SEC) und Flüssigphasenhochdruckchromatographie (HPLC) zur Anwendung im HT-Screening so beschleunigt werden kann, dass relative Molekulargewichtsverteilungen unterschiedlicher Polymere (PEG, PEO, Epoxidharze) bereits nach 2-6 Minuten pro Probe erhalten werden. [314] Bei der HT-Entwicklung von druckempfindlichen Klebstoffen nutzten Mehrabi und Mitarbeiter die Absorption von sichtbarem Licht in Verbindung mit einem Farbstoff zur Bestimmung der Filmdicke.…”

Section: Ht-untersuchungen Für Die Enwicklung Von Polymerenunclassified

Kombinatorische und Hochdurchsatz‐Techniken in der Materialforschung

2007

View full text Add to dashboard Cite

Hochdurchsatztechniken zur Entdeckung, Entwicklung und Optimierung von Materialien und Katalysatoren gewinnen zunehmend an Akzeptanz in der Industrie. Über die Jahre ist eine relative, synchron verlaufende Entwicklung von Techniken zur parallelisierten Herstellung und Charakterisierung mit dazugehöriger Software und Informationstechnologien zu verzeichnen. Im vorliegenden Aufsatz wird versucht, einen umfassenden Überblick über den Stand der Technik an ausgewählten Beispielen zu vermitteln. Datenbanken, “Design of Experiment”, Data‐Mining‐Techniken, Modellierungstechniken und Entwicklung evolutionärer Strategien werden ebenso angesprochen wie die vielen komplexen Materialien, für deren Erforschung bereits geeignete Techniken entwickelt wurden. Unterschiedlichste Methoden zur parallelisierten Synthese führen zu Einzelsubstanz‐ oder Gradientenbibliotheken für elektronische und optische Materialien ebenso wie für Polymere und Katalysatoren oder anhand von Formulierungsstrategien erzeugten Produkten. Viele Beispiele illustrieren die unterschiedlichsten Insellösungen und dokumentieren eine bisher kaum wahrgenommene Vielfalt an neuen Verfahren für Synthese und Analyse nahezu beliebiger Materialien. Der Aufsatz endet mit einer Zusammenfassung literaturbekannter Erfolge und einer Abschätzung von noch vorhandenen Problemen und Zukunftsaufgaben.

show abstract

Triple Tandem Catalyst Mixtures for the Synthesis of Polyethylenes with Varying Structures

Cited by 137 publications

References 26 publications

Combinatorial and High‐Throughput Materials Science

Combinatorial and High‐Throughput Materials Science

Nuclearity and cooperativity effects in binuclear catalysts and cocatalysts for olefin polymerization

Kombinatorische und Hochdurchsatz‐Techniken in der Materialforschung

Contact Info

Product

Resources

About