[PDF] Radical Polymerization Of Styrene In The Presence Of Nitroxyl Radicals Experiments And Simulations eBook

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Page : 5 pages
File Size : 17,60 MB
Release : 1996
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Polymerization of styrene in the presence of a stable radical TEMPO has been simulated using a Predici simulations package. Based on the experimental data, a kinetic model for the TEMPO-moderated polymerization of styrene has been proposed. It was shown that in order to properly simulate the experimental data, in addition to the reversible cleavage of the TEMPO-polymeric radical adduct, it is necessary to include thermal self-initiation, transfer and irreversible decomposition of intermediate alkoxyamines in the polymerization model. This model, combined with the experimental data and literature values of the rate constants of propagation (kp), termination (kt), transfer (ktrm), and alkoxyamines decomposition (kdecomp), was then employed to estimate kinetic and thermodynamic parameters of the exchange between dormant and active species. The equilibrium constant K was estimated to be around 1.10(exp -10) mol/L, the deactivation rate constant kd - 3.10(exp 7) mol-1Ls-1 and the activation rate constant ka= 3.10(exp -3)mol-1Ls-1 for bulk styrene polymerization at 120 deg C.

Author : Olivier Ouari
Publisher : Royal Society of Chemistry
Page : 611 pages
File Size : 18,27 MB
Release : 2021-05-13
Category : Science
ISBN : 1788019660

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Nitroxides are versatile small organic molecules possessing a stabilised free radical. With their unpaired electron spin they display a unique reactivity towards various environmental factors, enabling a diverse range of applications. They have uses as synthetic tools, such as catalysts or building blocks; imaging agents and probes in biomedicine and materials science; for medicinal antioxidant applications; and in energy storage. Polynitroxides (polymers bearing pendant nitroxide sidechains) have been used in organic radical batteries, oxidation catalysts and in exchange reactions for constructing complex architectures. Chapters in this book cover the synthesis of nitroxides, EPR studies and magnetic resonance applications, physiochemical studies, and applications including in batteries, imaging and organic synthesis. With contributions from leaders in the field, Nitroxides will be of interest to graduate students and researchers across chemistry, physics, biology and materials science.

Author : Carlos Federico Jasso-Gastinel
Publisher : William Andrew
Page : 233 pages
File Size : 40,12 MB
Release : 2016-09-14
Category : Technology & Engineering
ISBN : 0323443982

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Modification of Polymer Properties provides, for the first time, in one title, the latest information on gradient IPNs and gradient copolymers. The book covers the broad range of polymer modification routes in a fresh, current view representing a timely addition to the technical literature of this important area. Historically, blends, copolymers, or filled polymers have been developed to meet specific properties, or to optimize the cost/properties relationship. Using the gradient structure approach with conventional radical polymerization, it has been shown that it is possible to optimize properties if appropriate gradients in the composition of copolymer chains are obtained. An overview of the gradient structure approach for designing polymers has not appeared in the recent literature and this title covers the different methods used to modify properties, offering the whole range of ways to modify polymers in just one volume and making this an attractive option for a wide audience of practitioners. The approach for each chapter is to explain the fundamental principles of preparation, cover properties modification, describe future research and applications as examples of materials that may be prepared for specific applications, or that are already in use, in present day applications. The book is for readers that have a basic background in polymer science, as well as those interested in the different ways to combine or modify polymer properties. Provides an integrated view on how to modify polymer properties Presents the entire panorama of polymer properties modification in one reference, covering the essential information in each topic Includes the optimization of properties using gradients in polymers composition or structure

Author : Krzysztof Matyjaszewski
Publisher : OUP USA
Page : 0 pages
File Size : 14,35 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 : Peter A. Lovell
Publisher : John Wiley & Sons
Page : 858 pages
File Size : 41,94 MB
Release : 1997-04-03
Category : Science
ISBN :

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Emulsion Polymerization and Emulsion Polymers Edited by Peter A. Lovell Manchester Materials Science Centre, UMIST, Manchester, UK and Mohamed S. El-Aasser Emulsion Polymers Institute and Department of Chemical Engineering, Lehigh University, Bethlehem, PA, USA Emulsion polymerization is a technologically and commercially important reaction used to produce synthetic polymers and latexes for a wide range of applications. It is the basis of a massive global industry that is expanding due to the versatility of the reaction and the greater realization of the ability to control properties of the polymer latexes produced. Emulsion Polymerization and Emulsion Polymers provides an up-to-date treatment of both academic and industrial aspects of the subject in a single self-contained volume. Established knowledge is integrated with latest developments and introductory chapters to give a state-of-the-art summary which is also suitable as a broad based introduction to the field. The individual chapters have been written by specialists from academia and industry and are presented in a way which ensures that the book will be of equal value to experienced researchers and students.