Preparation of Telechelic Polymers Via Nitroxide Mediated Polymerization PDF Download
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Author: Gregory J. O'Bryan
Publisher:
ISBN:
Category :
Languages : en
Pages : 492
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Book Description
Author: Gregory J. O'Bryan
Publisher:
ISBN:
Category :
Languages : en
Pages : 492
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Book Description
Author: Didier Gigmes
Publisher: Royal Society of Chemistry
ISBN: 1782622632
Category : Science
Languages : en
Pages : 513
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Book Description
Nitroxide-mediated polymerization is an important branch of controlled radical polymerization, which has revolutionised the preparation of polymer architectures and compositions. This is the first book dedicated to the topic and covers the history and development of nitroxide-mediated polymerization, as well as current techniques of academic and industrial interest. Nitroxide-Mediated Polymerization gathers together and comprehensively discusses all aspects of nitroxide-mediated polymerization, from fundamental principles through to industrial applications. A specific focus will be dedicated to the principle of the technique, its kinetics aspects, the synthesis of the controlling agents, the range of polymerizable monomers, its potential for preparation of advanced organic and hybrid materials and its status at the industrial stage. The book details all stages of the field, with chapters detailing the history, recent developments and novel materials in this fast developing area. Edited and written by expert researchers working in the field and academia this book focuses on highlighting the kinetic aspects of nitroxide-mediated polymerization, providing insight into the kinetics that can sometimes be hard to follow in published papers. The book will be of interest to polymer chemists and materials scientists at graduate level and above.
Author: Chi Zhang
Publisher:
ISBN:
Category :
Languages : en
Pages :
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Book Description
"Stimuli-responsive polymers have been touted as "smart" due to their fast and reversible responses to environmental changes. It is imperative for these polymers to have well-defined structures so that their performance can be consistent and predictable. In order to achieve this, nitroxide mediated polymerization (NMP) was employed as the synthesis technique for the microstructured polymers that form the core of the investigations presented in this thesis. As one of the main controlled radical polymerization techniques, NMP stands out for its simplicity in both required ingredients and purification procedures. Many known stimuli-responsive polymers are poly(methacrylates). However, homopolymerization of methacrylates has been challenging for NMP mainly due to the large equilibrium constant that resulted in high concentration of active radicals and thus excessive irreversible terminations. By using a small amount of "controlling co-monomer" such as styrene, copolymerizations with methacrylate-rich feeds can be controlled using the commercially available alkoxyamine initiator BlocBuilderTM via NMP, featuring linear increases in number average molecular weight versus conversion, and narrow molecular weight distribution.In this thesis, two methacrylates, namely 2-(dimethylamino)ethyl methacrylate (DMAEMA) and benzyl methacrylate (BzMA), whose homopolymers exhibit LCST-type phase separation behaviours in aqueous and ionic liquid (IL) solutions, respectively, were copolymerized with various controlling co-monomers by NMP to demonstrate the versatility of NMP in tuning thermo-responsive properties. For both methacrylates, styrene was initially used as the controlling co-monomer to obtain copolymers with relatively narrow molecular weight distribution and ability to extend chains to form block copolymers when reinitiated with a fresh batch of monomer. 2-Vinylpyridine (2VP) was then chosen to copolymerize with DMAEMA for its lower hydrophobicity compared to styrene and pH-sensitivity, where about 2 - 5 mol% 2VP was shown sufficient to obtain well-defined DMAEMA/2VP copolymers. The detailed phase behaviour characterization of these DMAEMA-rich copolymers in aqueous solutions revealed the effects of important factors such as pH, copolymer composition, solution concentration and polymer microstructure, on the tuning of transition temperatures.For BzMA, 9-(4-vinylbenzyl)-9H-carbazole (VBK) was used as an alternative controlling co-monomer. Controlled and pseudo-"living" copolymerizations were achieved with as little as 2 mol% VBK in the feed, demonstrating significant improvement compared to the BzMA/styrene system. The incorporation of fluorescent VBK resulted in 5-fold fluorescence enhancement during the phase separation of BzMA/VBK copolymers from IL [C2mim][NTf2]. The enhancement resulted from heightened efficiency of the fluorescence resonance energy transfer (FRET) between BzMA and VBK during aggregation. However, the solvatophobicity of VBK also significantly reduced the solubility of BzMA/VBK copolymers in the IL and rendered the phase separation irreversible. Further investigation on the effects of solvatophilicity and chain mobility on phase separation and reversibility in ILs was carried out by incorporating varying amounts of solvatophilic co-monomer, namely methyl methacrylate (MMA) and oligo(ethylene glycol) methacrylate (OEGMA), yielding BzMA/MMA/VBK and BzMA/OEGMA/VBK terpolymers. It was found that molecular weight, glass transition temperature, and solution concentration all played important roles on phase separation temperature but sufficiently high solvatophilicity (quantified by the concentration of solvatophilic group) was essential to facilitate the re-dissolution process after phase separation. " --
Author: Eric J. Goethals
Publisher: CRC Press
ISBN: 1351093991
Category : Science
Languages : en
Pages : 474
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Book Description
This first-of-its-kind publication reviews the most impor-tant literature on the synthesis, properties, and applications of telechelic polymers. Written by a group of internationally known ex-perts in the field, this text contains a review table which allows the reader to search for given polymers with given end groups. Over 1,250 references are listed, covering primary and review articles as well as patents. Chapters include the preparation of telechelics by stepwise polymerization, anionic polymerization, radical polymer-ization, cationic polymerization, ring-opening polymerization and controlled polymer degradation. Polyols for the polyurethane pro-duction are described, as well as halato-telechelic polymers. Also, a more theoretical contribution on the physical properties of net-works formed from telechelic polymers is provided.
Author: Didier Gigmes
Publisher: Royal Society of Chemistry
ISBN: 1782620613
Category : Science
Languages : en
Pages : 512
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Book Description
The first book dedicated to nitroxide-mediated polymerization and covers the history and development of NMP, as well as current techniques of academic and industrial interest.
Author:
Publisher: Newnes
ISBN: 0080878628
Category : Technology & Engineering
Languages : en
Pages : 7752
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Book Description
The progress in polymer science is revealed in the chapters of Polymer Science: A Comprehensive Reference, Ten Volume Set. In Volume 1, this is reflected in the improved understanding of the properties of polymers in solution, in bulk and in confined situations such as in thin films. Volume 2 addresses new characterization techniques, such as high resolution optical microscopy, scanning probe microscopy and other procedures for surface and interface characterization. Volume 3 presents the great progress achieved in precise synthetic polymerization techniques for vinyl monomers to control macromolecular architecture: the development of metallocene and post-metallocene catalysis for olefin polymerization, new ionic polymerization procedures, and atom transfer radical polymerization, nitroxide mediated polymerization, and reversible addition-fragmentation chain transfer systems as the most often used controlled/living radical polymerization methods. Volume 4 is devoted to kinetics, mechanisms and applications of ring opening polymerization of heterocyclic monomers and cycloolefins (ROMP), as well as to various less common polymerization techniques. Polycondensation and non-chain polymerizations, including dendrimer synthesis and various "click" procedures, are covered in Volume 5. Volume 6 focuses on several aspects of controlled macromolecular architectures and soft nano-objects including hybrids and bioconjugates. Many of the achievements would have not been possible without new characterization techniques like AFM that allowed direct imaging of single molecules and nano-objects with a precision available only recently. An entirely new aspect in polymer science is based on the combination of bottom-up methods such as polymer synthesis and molecularly programmed self-assembly with top-down structuring such as lithography and surface templating, as presented in Volume 7. It encompasses polymer and nanoparticle assembly in bulk and under confined conditions or influenced by an external field, including thin films, inorganic-organic hybrids, or nanofibers. Volume 8 expands these concepts focusing on applications in advanced technologies, e.g. in electronic industry and centers on combination with top down approach and functional properties like conductivity. Another type of functionality that is of rapidly increasing importance in polymer science is introduced in volume 9. It deals with various aspects of polymers in biology and medicine, including the response of living cells and tissue to the contact with biofunctional particles and surfaces. The last volume is devoted to the scope and potential provided by environmentally benign and green polymers, as well as energy-related polymers. They discuss new technologies needed for a sustainable economy in our world of limited resources. Provides broad and in-depth coverage of all aspects of polymer science from synthesis/polymerization, properties, and characterization methods and techniques to nanostructures, sustainability and energy, and biomedical uses of polymers Provides a definitive source for those entering or researching in this area by integrating the multidisciplinary aspects of the science into one unique, up-to-date reference work Electronic version has complete cross-referencing and multi-media components Volume editors are world experts in their field (including a Nobel Prize winner)
Author: Olivier Ouari
Publisher: Royal Society of Chemistry
ISBN: 1788019660
Category : Science
Languages : en
Pages : 611
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Book Description
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: Aaron Nilsen
Publisher:
ISBN:
Category :
Languages : en
Pages : 1088
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Book Description
Author: J.M.G. Cowie
Publisher: Springer Science & Business Media
ISBN: 1475791399
Category : Technology & Engineering
Languages : en
Pages : 292
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Book Description
Examination of the early literature attests to the fact that the study of copolymerization was initiated when polymer science was in its infancy. It has continued to grow to a subject of major importance and has been a source of interest to both academic and industrialist alike. The wide spectrum of structures and properties available in the statistical copolymer has made this a fruitful field of exploration, but one particular and more restricted form which has held its own fascination for many is the limiting case of the strictly alternating copolymer. This is formed, in the ideal situation, when two monomers in a reaction mixture add consecutively to create a polymer chain with a regular {ABABAB} structure, irrespective of the monomer feed ratio. When this happens the resulting copolymer will always have the same composition, a feature which can be advantageous but also somewhat restrictive, as the ability to vary the properties is then limited. Within a series entitled Speciality Polymers it seems appropriate then to deal with this subject, particularly as no previous attempt has been made to draw together the various facets of alternating copolymerization into one volume. It also seems timely to present a more unified picture of the subject which will also illustrate the progress made.
Author: Xeniya Savelyeva
Publisher:
ISBN:
Category :
Languages : en
Pages :
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Book Description
"Controlled radical polymerization (CRP) techniques has allowed the synthesis of numerous polymeric materials with comparable control to that of true "living" techniques without the need for stringent manipulation techniques. The control over chain length, dispersity and composition is desirable in many fields, such as stimuli-responsive (temperature or pH) drug carriers. These thermoresponsive polymers in aqueous media are often characterized by lower critical solution temperature (LCST) behavior, where the polymer becomes insoluble with temperature increases. The LCST can be tuned by the structural features of the constituent monomer, molecular weight, molecular weight distribution and copolymerization with other monomers. Narrow molecular weight distribution is the key factor determining the sharpness needed for determining the LCST, which is often exemplified by the cloud point temperature (CPT). Using CRP techniques, specifically nitroxide mediated polymerization (NMP), with an alkoxyamine unimolecular initiator, 2-([tert-butyl[1-(diethoxyphosphoryl)-2,2-dimethylpropyl]amino]oxy)-2-methylpropanoic acid (BlocBuilder) and an additional free nitroxide (SG1), the effect of controlling comonomer (9-(4-vinylbenzyl)-9H-carbazole (VBK)) on polymerization kinetics of N-(2-methacryloyloxyethyl) pyrrolidone (MAEPYR) and the effect of final copolymer composition on CPT was studied. Adding at least 5 mol% VBK, the dispersity Đ of the poly(MAEPYR-stat-VBK) copolymers was below 1.4. The CPT decreased from 59.0 °C to 49.7 °C with addition of only 1 mol% of VBK in the copolymer, and it can be further fine-tuned by changing the solution concentration and the heating rate. Another CRP technique, reversible addition fragmentation chain-transfer polymerization (RAFT), was applied to homopolymerization of N-(3-methoxypropyl) acrylamide (MPAM) to yield well-defined polymers (with (M_n)− = 14.3 - 25.2 kg mol-1 and low Đ ~ 1.17 - 1.47) needed for precise determination of CPT. Thermoresponsive behaviour of poly(MPAM) in aqueous media revealed CPTs between 73 and 92 °C, unlike other literature reports where the polymers, synthesized by conventional radical polymerization, showed conflicting results regarding their LCST" --
