Download or read book Development of Functionalized Polymers Using Bis phenoxyimine titanium and alpha diimineNickel II Catalysts for the Production of New Polyolefin Architectures written by Amelia Marie Anderson and published by . This book was released on 2010 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Decades of research in the area of metal-catalyzed olefin polymerization, since the initial discoveries by Ziegler and Natta in the 1950s, has lead to the development of a wide variety of transition metal catalysts as well as numerous polymer architectures. Although early work in the field focused on heterogeneous catalysis, Kaminsky's discovery of the scavenger/activator methylaluminoxane in 1980 facilitated a renaissance in the area of homogeneous catalysts. Today, many commercial polyolefin materials are still limited to linear homopolymers, random copolymers, or blends thereof. Therefore, our efforts have focused on the endfunctionalization and random incorporation of polar functional groups into polyolefins to produce polymers with improved properties and more complex architectures than traditional linear polymers. Initial work in this area focused on the development of well-defined long-chain branched polymers from end-functionalized polypropylene. Although many star polymers have been produced using anionic, cationic and radical methods, semicrystalline polypropylene materials with similar structures from coordinationinsertion polymerization were not known. Using a non-living bis(phenoxyimine)titanium catalyst, allyl-terminated syndiotactic polypropylene was produced and utilized in the production of alcohol-, azide- and amine-terminated polymers. These end-functionalized macromolecules were employed in the synthesis of a variety of well-defined branched polymers including star, miktoarm star and H- polymers. In an effort to produce branched polyolefin materials with high molecular weight, a norbornene-terminated polymer was synthesized from the allyl-terminated syndiotactic polypropylene. Using ring-opening metathesis polymerization, a number of high molecular weight polypropylene comb polymers were produced. All of the branched, syndiotactic polypropylene materials were analyzed further in an effort to related branching with observed polymer properties. To produce polyolefins with improved properties, a series of random copolymers derived from propylene and a polar, hydrogen bonding monomer were produced using Ni(II) [alpha]-diiminecatalysts. By varying the reaction temperature, hydrogen bonding polypropylene materials with a range of microstructures were produced. At high reaction temperatures, regioirregular, amorphous polypropylene was obtained, whereas, decreasing reaction temperature lead to highly regioregular, isotactic polypropylene. Utilizing the living nature of the Ni(II) [alpha]-diiminecatalysts, a series of triblock copolymers containing hydrogen bonding moieties in the midblock were also produced. The mechanical properties of all materials were investigated and generally observed to improve upon incorporation of small amounts (~1%) of the ureidopyrimidinone. For the branched and hydrogen bonding polymer reported herein, functionalization of polypropylene allowed for the synthesis of new polyolefin architectures.

Download or read book New Polyolefin Architectures Through the Development of Living and Stereoselective Group IV Phenoxyketimine and Phenoxyamine Olefin Polymerization Catalysts written by Joseph B Edson and published by . This book was released on 2009 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Since the pioneering work by Ziegler and Natta in the 1950s on metalcatalyzed olefin polymerization, decades of research have led to the development of catalysts capable of furnishing a wide variety of polymers. Early work focused on heterogeneous catalysts, but the later development of homogeneous catalysts provided mechanistic insights that have allowed researchers to develop catalysts that provide access and control over specific polymer microstructures. The majority of commercial polyolefins has traditionally been limited to homopolymers, random copolymers, or blends thereof. In the past decade however, the development of olefin polymerization catalysts that are living have now allowed access to virtually a limitless number of new polyolefin architectures. Despite the fact that a living polymerization system is capable of producing only one polymer chain per metal center, the real advantage lies in the ability to synthesize well-defined block copolymers and identify new materials with promising properties. Our efforts have focused on C2-symmetric bis(phenoxyketimine) titanium dichloride complexes and C1-symmetric phenoxyamine zirconium and hafnium dibenzyl complexes supported by an sp3-C donor. We have shown that upon activation, these complexes can catalyze the living and isoselective polymerization of !-olefins. Using these, the synthesis of a number of new block copolymers featuring semicrystalline isotactic polypropylene segments and amorphous poly(ethylene-co-propylene) segments was accomplished. The resultant block copolymers displayed elastomeric behavior and excellent mechanical properties. We have further shown that catalysts derived from the C1-symmetric phenoxyamine zirconium and hafnium dibenzyl complexes are capable of the cyclopolymerization of 1,5-hexadiene. The resultant polymers were shown to have a previously unreported cis-isotactic microstructure.

Download or read book Catalyst Design for Tailor Made Polyolefins written by M. Terano and published by Elsevier. This book was released on 1994-11-01 with total page 437 pages. Available in PDF, EPUB and Kindle. Book excerpt: Recent development of olefin polymerization catalysts has caused marked changes in both industrial and academic research. Industrial use of homogeneous metallocene catalysts has already begun in the fields of high density polyethylene and syndiotactic polypropylene. Moreover, important data have been obtained from academic investigations which have proved useful for understanding conventional heterogeneous Ziegler-Natta catalysts. From the industrial viewpoint, however, heterogeneous high-yield catalysts seem to be more important. The present volume contains invited lectures and contributed papers. The following topics are covered: (1) Heterogeneous Catalysts, (2) Metallocene Catalysts and (3) New Trends in the Polyolefin Industry.

Download or read book Oligomerization and Polymerization of Ethylene by Phenoxy imine Titanium Catalysts written by Astrid Cordier and published by . This book was released on 2019 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: 1-hexene is one of the most important olefin used as comonomer for the production of value-added polyethylenes (HDPE, LLDPE). In the field of selective ethylene trimerization employing titanium-based catalysts, specific single tridentate phenoxy-imine complexes (SFI) display the highest activity and 1-hexene selectivity upon activation with methylaluminoxane (MAO). However, ethylene polymerization is an unavoidable side reaction affecting both 1-hexene selectivity and process operations. Although being a major drawback, the causes of polymerization remain a grey area since few studies were dedicated to its deciphering. To handle this challenge , an original “polymer-to-catalyst” strategy was implemented. An extensive temperature study (26-80°C) revealed that the highest 1-hexene activity is reached between 30 °C and 40 °C while polymer production is prominent above 50 °C. Polyethylenes obtained were analyzed by SEC, NMR DSC, and advanced segregation techniques (CEF, SIST, rheology). Molar masses above 10^5 g mol-1 were identified along with a 1-hexene content below 1 mol %. An increase of dispersity (Ɖ > 2) with temperature was ascribed to an evolution from single to multi-site polymerization catalysis. Kinetic studies proved that polymer is continuously produced even at short reaction time, for any reaction temperature. Other parameters (addition of 1-hexene, hydrogen and use of trimethylaluminum) were found to impair the trimerization selectivity and/or activity of the system. Nevertheless, it was possible to lower the selectivity in polyethylene by premixing the complex with MAO. After analyzing the possible routes for the polymerization catalyst formation, the hypotheses of temperature and MAO-induced complex alterations were considered. Regarding the latter, a molecular ligand-free Ziegler-Natta catalyst, modeled using TiCl4/MAO, and the synthesized (FI)Ti(III)Cl2 activated by MAO could not explain polymer production in the SFI system. Formation of a polymerization species upon thermal alteration of the SFI complex was evidenced. This [O-,N,O-]-type species displays common features regarding catalytic response to 1-hexene compared to the polymerization catalyst in the SFI system although it could not reach the same catalytic performances. The formation of a bis(phenoxy-imine) complex (FI)2TiCl2 was evidenced in this thesis and is a promising avenue worth exploring. Eventually, although the exact species has not yet been identified, this work enabled to guide the focus of further investigations on activation process and complex rearrangement by ligand mobility.

Download or read book Living Stereoselective Olefin Polymerizations Using Titanium Bis phenoxyimine Catalysts written by Andrew Felix Mason and published by . This book was released on 2006 with total page 644 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Metal Catalysts in Olefin Polymerization written by Zhibin Guan and published by Springer Science & Business Media. This book was released on 2009-03-31 with total page 262 pages. Available in PDF, EPUB and Kindle. Book excerpt: Polyolefin is a major industry that is important for our economy and impacts every aspect of our lives. The discovery of new transition metal-based catalysts is one of the driving forces for the further advancement of this field. Whereas the classical heterogeneous Ziegler-Natta catalysts and homogeneous early transition metal metallocene catalysts remain the workhorses of the polyolefin industry, in roughly the last decade, tremendous progress has been made in developing non-metallocene-based olefin polymerization catalysts. Particularly, the discovery of late transition metal-based olefin polymerization catalysts heralds a new era for this field. These late transition metal complexes not only exhibit high activities rivaling their early metal counterparts, but more importantly they offer unique properties for polymer architectural control and copolymerization with polar olefins. In this book, the most recent major breakthroughs in the development of new olefin polymerization catalysts, including early metal metallocene and non-metallocene complexes and late transition metal complexes, are discussed by leading experts. The authors highlight the most important discoveries in catalysts and their applications in designing new polyolefin-based functional materials.

Download or read book Handbook of Transition Metal Polymerization Catalysts written by Ray Hoff and published by John Wiley & Sons. This book was released on 2018-05-08 with total page 696 pages. Available in PDF, EPUB and Kindle. Book excerpt: Including recent advances and historically important catalysts, this book overviews methods for developing and applying polymerization catalysts – dealing with polymerization catalysts that afford commercially acceptable high yields of polymer with respect to catalyst mass or productivity. • Contains the valuable data needed to reproduce syntheses or use the catalyst for new applications • Offers a guide to the design and synthesis of catalysts, and their applications in synthesis of polymers • Includes the information essential for choosing the appropriate reactions to maximize yield of polymer synthesized • Presents new chapters on vanadium catalysts, Ziegler catalysts, laboratory homopolymerization, and copolymerization

Download or read book Development of New Catalysts for Living Polymerizations written by Phillip Dene Hustad and published by . This book was released on 2002 with total page 604 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Alkene Polymerization Reactions with Transition Metal Catalysts written by Yury Kissin and published by Elsevier. This book was released on 2008-03-10 with total page 607 pages. Available in PDF, EPUB and Kindle. Book excerpt: During the past 30 years, the field of alkene polymerization over transition metal catalysts underwent several major changes:1. The list of commercial heterogeneous Ziegler-Natta catalysts for the synthesis of polyethylene and stereoregular polyolefins was completely renewed affording an unprecedented degree of control over the polymer structure.2. Research devoted to metallocene and other soluble transition-metal catalysis has vastly expanded and has shifted toward complexes of transition metals with multidentate ligands.3. Recent developments in gel permeation chromatography, temperature-rising fractionation, and crystallization fractionation provided the first reliable information about differences between various active centers in transition-metal catalysts.4. A rapid development of high-resolution 13C NMR spectroscopy resulted in greatly expanded understanding of the chemical and steric features of polyolefins and alkene copolymers. These developments require a new review of all aspects of alkene polymerization reactions with transition-metal catalysts. The first chapter in the book is an introductory text for researchers who are entering the field. It describes the basic principles of polymerization reactions with transition-metal catalysts, the types of catalysts, and commercially manufactured polyolefins. The next chapter addresses the principal issue of alkene polymerization catalysis: the existence of catalyst systems with single and multiple types of active centers. The subsequent chapters are devoted to chemistry and stereochemistry of elemental reaction steps, structures of catalyst precursors and reactions leading to the formation of active centers, kinetics of polymerization reactions, and their mechanisms. The book describes the latest commercial polymerization catalysts for the synthesis of polyethylenes and polypropylene The book provides a detailed description of the multi-center nature of commercial Ziegler-Natta catalysts. The book devotes specialized chapters to the most important aspects of transition metal polymerization catalysts: the reactions leading to the formation of active centers, the chemistry and stereochemistry of elemental polymerization steps, reaction kinetics, and the polymerization mechanism. The book contains an introductory chapter for researchers who are entering the field of polymerization catalysis. It describes the basic principles of polymerization reactions with transition-metal catalysts and the types of commercially manufactured polyolefins and copolymersThe book contains over 2000 references, the most recent up to end of 2006.

Download or read book Progress in Olefin Polymerization Catalysts and Polyolefin Materials written by Takeshi Shiono and published by Elsevier. This book was released on 2011-09-22 with total page 299 pages. Available in PDF, EPUB and Kindle. Book excerpt: The First Asian Polyolefin Workshop introduces the recent developments and the research activities on polyolefin technology in Asia, which is becoming one of the important places in technology as well as in economy. Asian Countries have experienced remarkable economic growth in the last decade as represented by China. The Asian Polyolefin Workshop (APO) was planned to provide a venue for Asian scientists and engineers identifying and exploring the areas of common interests. The workshop was held in Nara on December 7th-9th, 2005, with more than 100 participants from China, Israel, India, Japan, Korea, Russia, Spain and Thailand. The following research topics were covered with 34 oral and 37 poster presentations; 1) Heterogeneous olefin polymerization catalysts Traditional Ziegler-Natta, Phillips, heterogenized metallocene and post metallocenes 2) Homogeneous olefin polymerization catalysts Traditional Ziegler-Natta, metallocene and post metallocenes 3) Precise synthesis of new polyolefins 4) Structure and properties of polyolefins 5) Engineering aspects of olefin polymerization * Presents the latest proceedings on polyolefin technology * The first book contributed by almost all the distinguished scientists in Asian countries* Contains papers not only from academia but also from industry

Download or read book Metallocene Catalyzed Polymers written by George M. Benedikt and published by Cambridge University Press. This book was released on 2008-12-10 with total page 398 pages. Available in PDF, EPUB and Kindle. Book excerpt: It has been estimated that within just ten years, over half of all polyolefins will be made by using metallocene catalysts. This ground-breaking volume from PDL brings togetherùfor the first timeùwork from dozens of world-renowned experts on the subject. Fifty chapters of peer-reviewed content offer insights into applications in automotive components, food packaging, insulating films, non-woven fabrics and medical markets, among others.

Download or read book Development of Late Transition Metal Insertion Polymerization Catalysts written by Tobias Friedberger and published by . This book was released on 2015 with total page 406 pages. Available in PDF, EPUB and Kindle. Book excerpt: Polyolefins are the number one commercially produced polymeric material by volume, and find ubiquitous uses as plastics, elastomers, and fibers. They are produced from gaseous olefins such as ethylene and propylene by the action of a transition metal catalyst. Despite tremendous academic and industrial efforts and successes in catalyst development over the past decades, the copolymerization of polar functionalized olefins with sufficiently high activities still remains a largely unsolved issue. Late transition metal catalysts were shown to be more suitable for this kind of polymerization reaction due to their generally lower oxophilic character. The main goal of this thesis was the development of novel late transition olefin polymerization catalysts based on ruthenium and palladium. Prior to this work, only few active olefin polymerization Ru-catalysts were reported. Several series of complexes based on ruthenium were synthesized, characterized and investigated for olefin polymerization. Ru(II)-complexes of the type RuCl2(N,N,N)L with facially coordinating nitrogen donor ligands (N,N,N = trispyridyl-, trispyrazoyl-, trisimidazoyl-methane derivatives) were found to be inactive towards ethylene polymerization. Employing bisanionic disulfonate phosphines as ligands gave Ru-complexes that produced linear, high-molecular weight polyethylene in the presence of an aluminum-alkyl based cocatalyst. Increasing the electrophilicity of the complex, by decreasing the donor strength of the ligand and using higher oxidation state Ru(IV)-complexes, the polymerization activity could be increased, and one of the highest activities for any Ru-based catalyst was observed. Polar additives such as acetone fully inhibited even the most electron-rich catalysts and copolymerization reactions yielded no polymer. In a different approach to solve the same problem, Pd-diimine complexes were modified with pendant olefin and boronate groups. Pd-diimine complexes can facilitate the copolymerization of ethylene with acrylates, and interactions of the pendant Lewis acid group with the functional, Lewis basic comonomer was anticipated to increase catalyst activity. However, no effect of a pendant pinacol boronate was observed on the incorporation ratio of methyl acrylate in room temperature copolymerizations. The ability of the pendant olefin to coordinate to cationic Pd-species resulted in hemilabile effects. Increased catalyst stability at the cost of decreased activities was found in comparison with unfunctionalized ligands.

Download or read book Beyond Metallocenes written by Abhimanyu O. Patil and published by . This book was released on 2003 with total page 272 pages. Available in PDF, EPUB and Kindle. Book excerpt: The past 15 years have witnessed tremendous advances in the design and use of organometallic complexes as precatalysts for olefin polymerization. Most recently, an intense search has been started in next-generation single-site catalysts. New approaches have been taken to ligand design. This research has yielded extraordinary results such as catalysts with activities as high or higher than those of conventional metallocenes, stereospecific and living polymerizations, and amazing new polymer structures such as highly-branched ethylene homopolymers. This volume presents some of the recent disclosures in this exciting and rapidly expanding field, featuring papers by some of the leading investigators.

Download or read book Catalytic Polymerization of Cycloolefins written by Valerian Drăguțan and published by Elsevier Science Limited. This book was released on 2000 with total page 1272 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book discusses in detail the relevant aspects of these processes including reaction thermodynamics, kinetics, mechanisms and stereochemistry and correlates the structure of produced polymers with their chemical and physical-mechanical properties. Related important topics include Ziegler-Natta polymerization of olefins and dienes, atom transfer radical polymerization of vinyl compounds, metathesis of olefins and acetylenes, acyclic diene metathesis reaction, carbonyl olefination reaction, metathesis polymerization of acetylenes, metathesis degradation of polymers and ring-opening polymerization of heterocycles. Special emphasis is laid upon the manufacture of commercial products, new polymers and copolymers of potential interest for industry and design and synthesis of speciality polymers with particular structures and architectures and desired properties.-

Download or read book Novel Titanium IV Catalysts for Olefin Polymerization written by Saman Damavandi and published by LAP Lambert Academic Publishing. This book was released on 2013 with total page 112 pages. Available in PDF, EPUB and Kindle. Book excerpt: The field of olefin polymerization has been remarkably renewed with the use of metallocene and post metallocene catalyst. Novel transition-metal complexes were studied as catalysts in ethylene polymerization. The aim of this work is to investigate the feasibility of replacing the cyclopentadienyl ligands of metallocenes by bis(aminotropone) ligands as well as by new bis(imino)pyridinato ligands without losing the good properties of the metallocenes, such as high activity and formation of linear polymer. It was presumed that the polymerization mechanism and the active center in ethylene polymerization would be similar for iminopyridinato and metallocene catalysts. Titanium (IV) and nickel (II) catalysts based on bis(anilinotropone) ligands were prepared and their structures determined to clarify the relationship between structure of the catalyst precursor and polymerization results. In experimentation, the syntheses, structures and olefin polymerization behavior of Ti complexes containing a pair of chelating aminotropone [O-N] ligands are reported. DFT studies revealed that bis(aminotropone) Ti complexes, when activated, provide a metal alkyl in the cis position to a vacant coordina

Download or read book Development of Late Transition Metal Catalysts and Advanced Polyolefins written by Nolan Evan Mitchell and published by . This book was released on 2018 with total page 183 pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation describes advances made within the Long Research Group to design single-site catalysts for olefin polymerizations, and for the synthesis of thermally cross-linkable polyolefins. We have 1) designed thermally robust Ni-based catalysts for ethylene polymerization, 2) expanded this thermal stability enhancement strategy to Co-based catalysts, and 3) developed thermally cross-linkable polyethylene that is facilitated by the rearrangement of a co-monomer. Catalysts employing late transition metals have been heavily studied for olefin polymerizations but their implementation in industry remains limited due to a variety of drawbacks. One specific limitation is the general thermal instability of these catalysts at temperatures commonly used for industrial polymerizations. We will herein demonstrate that the precatalyst bis[(2,6-dibenzhydryl-4-methylimino)acenaphthene] nickel(II) dibromide can be used to dramatically enhance the thermal stability of this family of Ni-based catalysts. This precatalyst proved to be thermally robust for ethylene polymerizations at temperatures as high as 90 °C and showing living polymerization behavior at temperatures as high as 75 °C. This bulky ligand was further expanded to sterically demanding Fe- and Co-based olefin polymerization catalysts bearing 2,6-bis(biphenylmethyl)-4-methylaniline substituted bis(imino)pyridine ligands were synthesized and evaluated for ethylene polymerization. Tthe extreme ligand bulk mitigated detectable chain-transfer to aluminum and associative chain-transfer events. These bulky Co catalysts display great thermal stability up to 80 °C and show enhanced thermal stability at 90 °C. These observations are attributed to the extreme steric demand by which the ligand mitigates catalyst transfer, deactivation, and decomposition. Lastly, materials that are accessible using catalysts currently employed in Industry. Industrial methods to cross-linked polyethylene are polymer irradiation and the incorporation of peroxides. These methods suffer from lack of control over cross-link bond formation and can result in a tacky polymer. We developed a thermally cross-linkable polyethylene that utilizes benzocyclobutene as a co-monomer. After polymerization, non-cross-linked films were formed and cross-linked by increasing the temperature to promote the thermal rearrangement of benzocyclobutene. These co-monomers can undergo cycloaddition with other activated benzocyclobutene co-monomers leading to covalently linked polyethylene chains. It will be demonstrated that cross-linking at temperatures above 200 °C yield cross-linked PEX films that show up to 82 % gel percent content.

Download or read book Organic Catalysis for Polymerisation written by Andrew Dove and published by Royal Society of Chemistry. This book was released on 2018-11-15 with total page 668 pages. Available in PDF, EPUB and Kindle. Book excerpt: In recent years polymerisation using organocatalysts has become an appealing alternative to more traditional metal-based catalysts. Conferring numerous advantages including low cost and ease of use, as well as the ability to precisely control the synthesis of advanced polymer structures, organocatalysts are increasingly used in polymer synthesis. Organic Catalysis for Polymerisation provides a holistic overview of the field, covering all process in the polymer synthesis pathway that are catalysed by organic catalysts. Sub-divided into two key sections for ease of use, the first focuses on recent developments in catalysis and the applications of catalysts to the full range of polymerisations that they have been utilised in; the second concerning monomers, arranges the field by monomer type and polymerisation mechanism. The book will therefore, provide a complimentary view of the field, providing both an overview of state-of-the-art catalyst development and also the best methodologies available to create specific polymer types. Edited by leading figures in the field and featuring contributions from researchers across the globe, this title will serve as an excellent reference for postgraduate students and researchers in both academia and industry interested in polymer chemistry, organic chemistry, catalysis and materials science.