[PDF] Chain End Functionalization Of Polymers Prepared By Nitroxide Mediated Polymerization eBook

Author : Didier Gigmes
Publisher : Royal Society of Chemistry
Page : 513 pages
File Size : 15,3 MB
Release : 2015-12-08
Category : Science
ISBN : 1782622632

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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 : Michael Olechnowicz
Publisher :
Page : 196 pages
File Size : 40,70 MB
Release : 2008
Category : Addition polymerization
ISBN :

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"The synthesis of homopolymers and block copolymers containing metal coordinating ligands is an important area of research due to the potential applications of these polymers in the fields of optics, electronics, and photonics. Specifically, the terpyridine group is very useful, since it can act as a tridentate chelating ligand due to its strategically positioned, three nitrogen atoms. This allows it to form strong complexes with a variety of transition metal ions. The hydroxyl functionality is another important group due to numerous applications of well-defined hydroxyl-functionalized polymers. They can react with other functional groups on other polymers for chain extension, branching, or crosslinking. They can also be used as macroinitiators for the polymerization of other monomers such as lactide and lactone. Alkyllithium-initiated, living anionic polymerization offers excellent control over molecular weight and molecular weight distribution. The absence of termination and chain transfer steps makes these systems ideally suited for the preparation of chain-end functionalized polymers by the reaction of the living chain ends with appropriate monomers or terminating agents. A recently reported general anionic functionalization method was used to create well-defined terpyridine and hydroxyl end-functionalized polymers. In the first step, living polymeric organolithium compounds were reacted with silyl chlorides to form the corresponding silyl hydride-functionalized polymers. Then, these polymers were reacted with substituted alkenes in the presence of a hydrosilation catalyst to form the corresponding functionalized polymers. A new method was also developed, based on similar chemistry, to prepare an in-chain functionalized diblock copolymer where a variety of functional groups can be placed directly at the interface of the two blocks. This method was used to prepare both in-chain hydroxyl- and terpyridine-functionalized polystyrene-b-polyisoprene copolymers. Lewis bases effect dramatic changes in microstructure, initiation rates, propagation rates and monomer reactivity ratios for alkyllithium-initiated polymerizations of vinyl monomers in hydrocarbon solution. The stability of polymeric organolithium compounds and the mechanism of decomposition in the presence of various stoichiometric equivalents of tetrahydrofuran in benzene solutions were studied due the importance of THF as an additive."--Abstract.

Author :
Publisher :
Page : 0 pages
File Size : 11,50 MB
Release : 1999
Category :
ISBN :

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We have recently shown that replacement of TEMPO as the mediating nitroxide in 'living' free radical polymerizations by alpha-hydrogen derivatives leads to monomer selection and functional group compatability approaching that of ATRP based systems. The ability of these new alkoxyamines, such as 1, to mediate the homopolymerization of a wide variety of monomers should permit a much greater range of well defined random, block, and star copolymers to be prepared under simplified conditions.

Author : Sumana Roy Chowdhury
Publisher :
Page : 192 pages
File Size : 50,53 MB
Release : 2006
Category : Addition polymerization
ISBN :

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"The objective of this work was to anionically synthesize well-defined polymers having functional groups either at the chain-end or along the polymer chain. General functionalization methods (GFM) were used for synthesizing both kinds of polymers. Chain-end functionalized polymers were synthesized by terminating the anionically synthesized, living polymer chains using chlorodimethylsilane. Hydrosilation reactions were then done between the silyl-hydride groups at the chain-ends and the double bonds of commercially available substituted alkenes. This produced a range of well-defined polymers having the desired functional groups at the chain ends. In-chain functionalized polymers were synthesized by anionically polymerizing a silyl-hydride functionalized styrene monomer: (4-vinylphenyl)dimethylsilane. Polymerizations were done at room temperature in hydrocarbon solvents to produce well-defined polymers. Functional groups were then introduced into the polymer chains by use of hydrosilation reactions done post-polymerization. The functionalized polymers produced were characterized using SEC, 1H and 13C NMR, FTIR, MALDI TOF mass spectrometry and DSC. The monomer reactivity ratios in the copolymerization of styrene with (4-vinylphenyl)dimethylsilane were also measured. A series of copolymerizations was done with different molar ratios of styrene(S) and (4-vinylphenyl)dimethylsilane(Si). Three different methods were used to determine the values of the monomer reactivity ratios: Fineman-Ross, Kelen-Tudos and Error-In-Variable (EVM) methods. The average values of the two monomer reactivity ratios obtained were: r(Si) =0.16 and r(S) = 1.74. From these values it was observed that in the copolymerization of styrene with (4-vinylphenyl)dimethylsilane, the second monomer was preferentially incorporated into the polymer chain. Also, r(Si)r(S) = 0.27, which shows that the copolymer has a tendency to have an alternating structure. Amino acid-functionalized polymers (biohybrids) were synthesized by using a simple and efficient, three-step method. The first step was to make a copolymer of styrene with (4-vinylphenyl)dimethylsilane, followed by introduction of amine functional groups into the polymer chain, suing a hydrosilation reactions between the silyl-hydride units in the copolymer chain and the double bond of allyl amine. The third step was a condensation reaction between these amine functional groups on the copolymer chain and the carboxyl group on N-carbobenzyloxy-phenylalanine (a protected amino acid). Although this method has been used to incorporate a particular amino acid onto the polymer chain, it maybe possible to extend this procedure to introduce virtually any amino acid or peptide group into the polymer chain. Finally a thermoplastic elastomer (TPE) was synthesized using the monomer (4-vinylphenyl)dimethylsilane. The first block of this TPE was a copolymer block of styrene with (4-vinylphenyl)dimethylsilane, followed by a polyisoprene block and finally another copolymer block of styrene and (4-vinylphenyl)dimethylsilane. This polymer was characterized using SEC, 1H and 13C NMR, FTIR, DSC, DMTA, TEM and tensile testing. It was seen to exhibit properties similar to those of a regular styrene-diene-styrene TPE. However, the silyl-hydride units introduced into this polymer chain can be easily converted to different functional groups using hydrosilation reactions. Introduction of such functional groups would be helpful in tailoring the properties of the TPE."--Abstract.

Author : Nikhil K. Singha
Publisher : Walter de Gruyter GmbH & Co KG
Page : 302 pages
File Size : 48,2 MB
Release : 2020-01-20
Category : Technology & Engineering
ISBN : 3110643693

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This book describes strategies and mechanism of reversible deactivation radical polymerization (RDRP) to synthesize functional polymers. Several approaches such as atom transfer radical polymerization and the combination of click chemistry and RDRP are summarized. Contributors from interdisciplinary fields highlight applications in nanotechnology, self-healing materials, oil and water resistant coatings and controlled drug delivery systems.