[PDF] Kinetic Investigation Of The Atom Transfer Radical Polymerization Of Styrene In Homogeneous Systems eBook

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Page : 5 pages
File Size : 44,55 MB
Release : 1996
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Controlled/'Living' radical polymerization allows for the preparation of complex polymer architectures, end functional polymers and block copolymers. Recently, we reported atom transfer radical polymerization (ATRP), a novel route to the controlled - 'Living' - radical polymerization in which polymers with predetermined molecular weight up to Mn =100,000 and polydispersity as narrow as 1.05 have been obtained. In this paper, the kinetic scheme of atom transfer radical polymerization of styrene under homogeneous conditions is described. The polymerization was determined to be first order with respect to the concentration of monomer, initiator and Cu(I) halide. From the effect of the ratio of ligand to Cu(I) halide, possible active copper complex was proposed.

Author : Krzysztof Matyjaszewski
Publisher : OUP USA
Page : 0 pages
File Size : 14,72 MB
Release : 2007-01-04
Category : Science
ISBN : 9780841239913

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The preparation and characterization of new materials with precisely controlled macromolecular dimensions, functionalities, and decomposition, as well as with well-defined topologies, is perhaps the main focus of contemporary polymer synthesis. The best control of molecular functions can be achieved in a controlled/living polymerization -- a chain growth process without chain breaking reactions. Recently, controlled/living polymerizations have extended to radical systems which are not only commercially important, but also have the largest potential due to the availability of radically polymerizable monomers, facile copolymerization and undemanding experimental conditions. Controlled Radical Polymerization will examine recent advances in mechanistic and synthetic aspects of controlled/living radical (co)polymerization systems. Not only will this book be focused on recent progress in the dynamically developing field of controlled/living radical polymerization, but it will be a sequel to the very popular ACS Symposium Series 685, 768, and 854. The book will consist of >30 chapters separated into seven subsections: Fundamentals, Mechanism of ATRP, Mechanisms of SFRP and Degenerative Transfer Processes, Controlled Architecture by CRP, Organic-inorganic Hybrids by CRP, Biomaterials by CRP and Industrial Applications. This book targets chemists and polymer scientists in academia and in industry.

Author : Krzysztof Matyjaszewski
Publisher : John Wiley & Sons
Page : 934 pages
File Size : 29,33 MB
Release : 2003-04-14
Category : Technology & Engineering
ISBN : 0471461571

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Klassische und moderne Verfahren der radikalischen Polymerisation: In diesem handlichen Band finden Sie Antworten auf theoretische und praktische Fragen. Neben grundlegenden Ausführungen zur Einteilung radikalischer Polymere sind Angaben über die wichtigsten experimentellen Verfahren zur Synthese, Reinigung und Charakterisierung von Polymeren enthalten. Interessante Zugabe: ein Abriß der Geschichte der Radikalkettenpolymerisation.

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Page : 5 pages
File Size : 31,86 MB
Release : 1996
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Kinetic aspects of Atom Transfer Radical Polymerization of methyl acrylate MA were studied. The results showed the characteristic features of living polymerization up to Mn (80,000, e.g. constant concentration of propagating species, a linear relation between conversion and molecular weight and narrow polydispersities (Mw/Mn (1.2). As an initiation system, 2- bromomethyl propionate and CuBr complexed by 4,4'-Di-tert-butyl-2,2'-bipyridine DThipy or 4,4'-di-(5-nonyl)-2,2'-bipyridine DNbipy were employed. Kinetic studies showed that the propagation rate is first order in relation to the monomer and initiator. For the homogeneous catalyst system (copper(I)/dNbipy), the propagation rate is first order with respect to the initial concentration of catalyst and inverse first order with respect to the initial concentration of Cu(II)Br2. The propagation rate in non-homogeneous system (copper(I)/dTbipy) less depends on the on the initial concentration of catalyst and Cu(II)Br2. These results can be explained by the reversible formation of growing polyacrylate radicals by the reaction of dormant bromo-terminated chains with copper halide.

Author : Richard Oluwarotimi Ademola Osibanjo
Publisher :
Page : pages
File Size : 41,71 MB
Release : 2013
Category :
ISBN : 9781303792458

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The big picture for this work is the development of a biosensor that will determine contaminants in aqueous systems via surface-bound thin films. In order to make this a reality, it is important to have an understanding of the initial stages during polymerization. Details of the mechanisms and structures created in the earliest stages of surface-bound polymer films affect the nature and structure of the films in profound ways. The two major methods on tethering polymers onto various substrates are the "grating from" and the "grafting to" methods. This study used the grafting from approach owing to its ability to produce denser grafting densities and thus produce thicker films. This study investigates the stability, structure, kinetics and density of initiator binding to Au surfaces and formulation of polymers via atom transfer radical polymerization (ATRP) on Au surfaces at low temperatures (25 -50 °C). Though restricted by the lability of thiol-gold at 50 °C, advantages of lower temperatures includes; absence of side reactions, chain transfer reactions, thermal crosslinking and increased quality of the produced polymer film. Time-dependent molecular information is obtained in situ from deposition of thiol-based initiator on the substrate, addition of monomer and catalyst during surface initiated ATRP on a Au substrate.Surface initiated atom transfer radical polymerization (SI-ATRP) is accompanied by tethering an initiator molecule such as 11-Mercaptobromoisobutyrate bromides onto a gold surface via formation of a Au-S bond. As a monolayer of the compound binds to the surface, the chains line up to form a quasi-crystalline self-assembled monolayer. The bromine can be abstracted with a catalyst, such as CuBr/CuBr2 or photochemically to produce a radical which then takes part in polymerization. ATR-FTIR is the method of choice because it is a surface specific technique and information regarding the nature of the adsorbed initiator molecule and details concerning polymer orientation desorption, mechanisms and kinetics can be obtained. These studies will contribute to further understanding the implementation of overlayer enhancement for IR spectroscopy at interfaces and understanding of the structure and dynamics of supported polymer films. It will also help provide an in depth look into the reactions of thin films and the development of thin film sensor technologies. Research into newer catalysts may be required for Cu-SI-ATRP owing to findings showing that Cu catalysts aide the desorption of thiol based initiator molecules which result in extensive termination reactions and production of thin films.

Author : Michael Buback
Publisher : John Wiley & Sons
Page : 270 pages
File Size : 12,5 MB
Release : 2007-07-16
Category : Technology & Engineering
ISBN : 3527320563

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The IUPAC-sponsored International Symposium on "Radical Polymerization: Kinetics and Mechanism" was held in Il Ciocco (Italia) during the week September 3-8, 2006. It was the fourth within the series of so-called SML conferences, which are the major scientific forum for addressing kinetic and mechanistic aspects of free-radical polymerization and of ontrolled radical polymerization. Top international authors like K. Matyjaszewski, T. P. Davis, T. Fukuda and others present their latest research. The five major themes covered were: Fundamentals of Free-Radical Polymerization, Heterogeneous Polymerization, Controlled Radical Polymerization, Polymer Reaction Engineering, and Polymer Characterization. SML IV again marked an important step forward toward the better understanding of the kinetics and mechanism of radical polymerization, which is extremely relevant for both conventional and controlled radical polymerization and for people in academia as well as in industry.

Author : Jose Asua
Publisher : John Wiley & Sons
Page : 392 pages
File Size : 12,1 MB
Release : 2008-04-15
Category : Technology & Engineering
ISBN : 0470691425

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Polymers are an example of “products-by-process”, where the final product properties are mostly determined during manufacture, in the reactor. An understanding of processes occurring in the polymerization reactor is therefore crucial to achieving efficient, consistent, safe and environmentally friendly production of polymeric materials. Polymer Reaction Engineering provides the link between the fundamentals of polymerization kinetics and polymer microstructure achieved in the reactor. Organized according to the type of polymerization, each chapter starts with a description of the main polymers produced by the particular method, their key microstructural features and their applications Polymerization kinetics and its effect on reactor configuration, mass and energy balances and scale-up are covered in detail. The text is illustrated with examples emphasizing general concepts, principles and methodology. Written as an authoritative guide for chemists and chemical engineers in industry and academe, Polymer Reaction Engineering will also be a key reference source for advanced courses in polymer chemistry and technology.

Author : Susheel Kalia
Publisher : Springer
Page : 390 pages
File Size : 11,69 MB
Release : 2014-12-04
Category : Technology & Engineering
ISBN : 3319135937

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Advances in Polymer Science enjoys a longstanding tradition and good reputation in its community. Each volume is dedicated to a current topic, and each review critically surveys one aspect of that topic, to place it within the context of the volume. The volumes typically summarize the significant developments of the last 5 to 10 years and discuss them critically, presenting selected examples, explaining and illustrating the important principles, and bringing together many important references of primary literature. On that basis, future research directions in the area can be discussed. Advances in Polymer Science volumes thus are important references for every polymer scientist, as well as for other scientists interested in polymer science - as an introduction to a neighboring field, or as a compilation of detailed information for the specialist.