Synthesis and Characterization of New Multifunctional Initiators for Anionic Polymerization and the Use of Poly(4-hydroxystyrene) as a Template for New Polymers PDF Download
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Author: Christopher Michael Hurley
Publisher:
ISBN:
Category : Addition polymerization
Languages : en
Pages : 151
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Book Description
This dissertation explores the synthesis and use of multifunctional anionic polymerization initiators for the purpose of opening the gateway to the synthesis of polymer architectures of greater complexity. First the multifunctional oxyanion initiator generated by reacting poly(4-hydroxystyrene) with sodium hydride was used to synthesize a previously unknown polymer containing an aryl halide functional group. The homopolymer solution self-assembly behavior of poly(4-hydroxystyrene) and the newly synthesized poly (4-(4-bromophenyloxy)styrene) were both investigated. This is followed by the synthesis and characterization of multifunctional alkyne core molecules and random copolymers of polystyrene-co-poly(4-hydroxystyrene) which served as templates for the synthesis of new random copolymers of polystyrene-co-poly(4-(2- propynyloxy)styrene). The newly formed multifunctional alkyne core molecules and alkyne functionalized random copolymers served as polymer backbones in a "grafting to" strategy. Previously prepared azide terminated polymers were grafted to the multifunctional alkyne core molecules and polymer backbones by copper (I) catalyzed alkyne-azide cycloaddition reactions. Lastly, the synthesis of a new hydrocarbon soluble multifunctional initiator was undertaken. The resulting molecule was shown to be an efficient initiator of anionic polymerization in non-polar solvent in the absence of polar additives, necessary in all previous attempts to combat large scale aggregation of such multifunctional initiator. This new initiator will open the way to facile synthesis of well-defined star polymers, star-block copolymers, and more complex polymer architectures.
Author: Christopher Michael Hurley
Publisher:
ISBN:
Category : Addition polymerization
Languages : en
Pages : 151
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Book Description
This dissertation explores the synthesis and use of multifunctional anionic polymerization initiators for the purpose of opening the gateway to the synthesis of polymer architectures of greater complexity. First the multifunctional oxyanion initiator generated by reacting poly(4-hydroxystyrene) with sodium hydride was used to synthesize a previously unknown polymer containing an aryl halide functional group. The homopolymer solution self-assembly behavior of poly(4-hydroxystyrene) and the newly synthesized poly (4-(4-bromophenyloxy)styrene) were both investigated. This is followed by the synthesis and characterization of multifunctional alkyne core molecules and random copolymers of polystyrene-co-poly(4-hydroxystyrene) which served as templates for the synthesis of new random copolymers of polystyrene-co-poly(4-(2- propynyloxy)styrene). The newly formed multifunctional alkyne core molecules and alkyne functionalized random copolymers served as polymer backbones in a "grafting to" strategy. Previously prepared azide terminated polymers were grafted to the multifunctional alkyne core molecules and polymer backbones by copper (I) catalyzed alkyne-azide cycloaddition reactions. Lastly, the synthesis of a new hydrocarbon soluble multifunctional initiator was undertaken. The resulting molecule was shown to be an efficient initiator of anionic polymerization in non-polar solvent in the absence of polar additives, necessary in all previous attempts to combat large scale aggregation of such multifunctional initiator. This new initiator will open the way to facile synthesis of well-defined star polymers, star-block copolymers, and more complex polymer architectures.
Author: Yusuf Ziya Menceloğlu
Publisher:
ISBN:
Category :
Languages : en
Pages :
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Book Description
In this study new multifunctional initiators were synthesized and their polymerization ability were studied. Bi and multifunctional initiators for block and star polymerization have been synthesized by using insertion reaction of tetrakis(dimethyl-amino)-titan (T4) with a,a'-azo-isobutyronitrile (AIBN), T4 with tetracyanoethylene(TCE) and T4 with isophorone diisocyanate (IPDI) respectively, in dry benzene under the nitrogen blanket at 35 oC. New cationic initiators; N-benzyl phthalimide derivatives,N-(a-methylbenzyl) benzothiazoloneandbenzyl benzenesulfonate which have no inorganic salt structure have been synthesized by the reaction of phthalimide, 4-nitro phthalimide, benzothiazolone and benzenesulfonyl chloride with benzyl, alpha and para substituted benzyl halides in the presence of base. All initiators were characterized byphysicochemical, spectral and analytical data. Polymerization ability of these initiators were studied with common monomers such as styrene acrylonitrile (AN)glycidyl phenyl ether (GPE), cyclohexene oxide (CHO), trimethylene oxide (TMO), 2-methyl aziridine (MA) and hydroxyl terminated polybutadiene (Poly bd, R-45 HT). This work suggests that bifunctional initiator 2,2'- azobis isobutyro(tris N"-dimethyl amino titanium-N,N dimethyl)amidin (T4-AZO1) is effective for the synthesis of block copolymer of acrylonitrile with radicalic polymerizable monomers, multifunctional initiators Tetrakis(2 dimethyl amino, N"titanamidin) 2,azoisobutyronitrile (T4-AZO4), Tetra(N'dimethylamino-tris Tetrakis (3,methylene-N dimethyl ureido titanium) 3,5,5 trimethyl cyclohexyl isocyanate or Tetrakis (N'dimethyl N titanium ureido)3,5,5 trimethyl cyclohexyl isocyanate (T4 IPDI4 )are capable for preparing star shape polymers from radicalic polymerizable monomers by decomposition of azo groups incorporated to the related initiators and acrylonitrile by insertion polymerization, furthermore ,model network of hydroxyl terminated polybutadiene was achieved using four-fonctional isocyanate compound T4-IPDI4 via urethane bond formation. Neutral organic compound containing benzylic group bound to low nucleophilic moiety can thermally initiate the cationic polymerization of a 2-methyl aziridine and trimethylene oxide.
Author: Maurice Morton
Publisher: Elsevier
ISBN: 0323158846
Category : Science
Languages : en
Pages : 257
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Book Description
Anionic Polymerization: Principles and Practice describes the unique nature of the anionic mechanism of polymerization. This book is composed of two parts encompassing 11 chapters that cover the aspects of the synthetic possibilities inherent in this system. Part I deals with the various aspects of anionic polymerization mechanism, including the monomers, initiators, solvents, and the involved initiation and propagation reactions. This part also describes the copolymerization and organolithium polymerization reactions of styrene and dienes. Part II explores the applications of anionic polymerization in polymer synthesis. This part specifically tackles the synthesis of narrow molecular weight, branched and a,?-difunctional polymers, and block copolymers. Polymer chemists and researchers who work in the chemical industry and who would wish to utilize the unique features of anionic polymerization in the synthesis of new products will find this book invaluable.
Author: Lutz Hellmut Feldmann
Publisher:
ISBN:
Category : Anions
Languages : en
Pages : 174
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Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 5
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Book Description
Polyphosphazenes are a new polymers with unique properties which include a combination of high temperature stability, low temperature flexibility, low surface energy, biofriendliness, and inflammability. We focused our research on polymerization of phosphoranimines catalyzed by Lewis acids and Lewis bases and synthesis of poly(diarylphosphazenes) by silyl azide intermediates and characterized the new polymers and copolymers using various techniques. The catalyzed polymerization of phosphoranimineshas been successfully used for the synthesis of random copolymers and the first block copolymers between two different polyphosphazenes. Additionally, we prepared polyphosphazene-organic polymer diblock structures using macromolecular phosphoranimines. The second part of the research was devoted to the preparation of new branched and hyperbranched polymers by controlled radical polymerization. We used atom transfer radical polymerization (ATRP) to prepare hyperbranched polystyrenes and polyacrylates. In addition, the novel class of compounds being simultaneously monomers and initiators (AB* monomers or inimers) were used successfully to design and prepare polymers and copolymers with novel topologies, compositions and functionalities. We prepared first molecular bottle-brush structures, multi arm star block and star diblock copolymers and also novel polar thermoplastic elastomers by entirely radical processes.
Author: Manuela Ocampo
Publisher:
ISBN:
Category : Addition polymerization
Languages : en
Pages : 210
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Book Description
Novel methods for the synthesis of chain-end and in-chain functionalized polymers, as well as star polymers, were developed using anionic polymerization techniques. A new mechanism for the reaction of polymeric organolithium compounds with thiiranes has been found. The reaction of poly(styryl)lithium and poly(butadienyl)lithium with propylene sulfide and ethylene sulfide was investigated in hydrocarbon solution for the preparation of thiol-functional polymers. It was found by MALDI-TOF mass spectral analysis of the reaction products that the reaction proceeded by attack of the anion on the methylene carbon atom of the thiirane ring followed by ring opening to form the thiol-functionalized polymer. The reaction of poly(styryl)lithium with trimethylene sulfide did not produce the corresponding thiol-functionalized polymer; the resulting methyl-terminated polymer was formed by attack of the anion on the sulfur atom followed by ring opening to form a primary carbanion. A new method for synthesis of alkoxysilyl-functionalized polymers was developed. Using a general functionalization methodology based on the hydrosilation of vinyltrimethoxysilane with [omega]-silyl hydride-functionalized polystyrene, alkoxysilyl-functionalized polystyrene was obtained in high yield (83 %). The main side product was vinylsilane-functionalized polymer. A small amount of dimer (approximately 2 %) was formed from the hydrosilation reaction of silyl hydride-functionalized polymer and vinylsilane-functionalized polymer. Star polymers with an average number of 6.8 arms were obtained by reacting poly(styryl)lithium with 6.6 equivalents of vinyldimethylchlorosilane in benzene at 30 °C. It was found that, in benzene at 30 °C, vinyldimethylchlorosilane is an efficient linking agent for the preparation of well-defined star-branched polymers. In contrast, the reaction of poly(styryl)lithium with 5 equivalents of vinyldimethylchlorosilane in THF at -78 °C produced vinylsilane-functionalized polymer in high yield (> 93 %). Poly(styryl)lithium was reacted with 2.5 equivalents of vinyldimethylethoxysilane; reaction occurred exclusively by the addition of the living anion to the vinyl group. In-chain, dihydroxyl-functionalized polystyrene was prepared by reaction of poly(styryl)lithium and 1,3-butadiene diepoxide. The hydroxyl functionalities were activated with potassium naphthalenide. Addition of ethylene oxide monomer yielded the corresponding heteroarm polystyrene/poly(ethylene oxide) stars. Two commercially available triepoxides, N,N-diglycidyl-4-glycidyloxyaniline and Tactix 742, were used to prepare the corresponding 3-armed stars in high yield.
Author: Michael Olechnowicz
Publisher:
ISBN:
Category : Addition polymerization
Languages : en
Pages : 196
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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: Youngjoon Lee
Publisher:
ISBN:
Category : Addition polymerization
Languages : en
Pages : 372
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Author: Sung Hoon Jang
Publisher:
ISBN:
Category : Addition polymerization
Languages : en
Pages : 602
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Author: Jonathan E. Janoski
Publisher:
ISBN:
Category : Addition polymerization
Languages : en
Pages : 160
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Book Description
The synthesis of well-defined functionalized polymers is an important area of research due to their wide array of applications. The work presented herein can be divided into three categories: a) functional initiator synthesis; b) chain-end and in-chain functionalization and c) functional monomer synthesis and polymerization. All three methods involve both anionic polymerization and hydrosilation. In this work, all anionic polymerizations were performed at room temperature in hydrocarbon solvent with an alkyllithium initiator. A functional 4-pentenyllithium initiator was prepared in 70% yield and was used for the synthesis of [alpha] and [alpha,omega]-functionalized polystyrene. 4-Pentenyllithium was used to initiate styrene polymerization in benzene in the presence of 5 equivalents of tetrahydrofuran. Narrow polydispersity indices and good agreement between calculated and observed molecular weights were observed for the methanol-terminated product. [alpha]-Triethoxysilyl-functionalized polystyrene was quantitatively prepared by hydrosilation with triethoxysilane and [alpha]-4-pentenylpolystyrene. [alpha]-4-Pentenyl-[omega]-silyl hydridefunctionalized polystyrene and [alpha]-4-pentenyl-[omega]-thiol hydride functionalized polystyrene were quantitatively prepared by terminating [alpha]-4-pentenylpoly(styryl)lithium with chlorodimethylsilane and ethylene sulfide, respectively. The [alpha]-4-pentenyl-[omega]-silyl hydride-functionalized polystyrene showed good agreement between calculated and observed molecular weights and a narrow polydispersity. [alpha]-4-Pentenyl-[omega]-thiolfunctionalized polystyrene showed a dimer peak due to oxidative coupling when quenched with methanol. Triethoxysilyl-functionalized, high-1,4-polybutadiene was prepared by reacting the pendant double bonds of the 1,2-units with triethoxysilane via hydrosilation. High-yielding reactions between the polymeric organolithium chain-ends and silyl chlorides were used to obtain the desired polymeric silyl hydrides for further functionalization. In-chain and chain-end cyano-functionalized polystyrenes were prepared. Chain-end, silyl hydride-functionalized polystyrene was prepared quantitatively. Hydrosilation of chain-end, silyl hydride-functionalized polystyrene with allyl cyanide resulted in [omega]-cyano-functionalized polystyrene, which was prepared in 87% yield. In-chain, silyl hydride-functionalized polystyrene was prepared by terminating excess poly(styryl)lithium with dichloromethylsilane. The remaining poly(styryl)lithium was terminated with ethylene oxide to aid in chromatographic separation to yield the pure in-chain, silyl hydride-functionalized polystyrene in 96% yield. Hydrosilation of in-chain, silyl hydride-functionalized polystyrene with allyl cyanide resulted in cyano in-chain functionalized polystyrene in 58% yield after 2 weeks of reaction time at elevated temperature. [omega]-Silyl dihydride-functionalized polystyrene was prepared in 92% yield by inverse addition of poly(styryl)lithium to dichloromethylsilane then reduction with lithium aluminum hydride. Functionalization with allyl cyanide yielded [omega]-dicyanofunctionalized polystyrene quantitatively. Synthesis of functionalized polymers from silyl hydride-substituted monomers was also investigated. para-Dimethylsilylstyrene was prepared from 4-chlorostyrene in 84% yield. Homopolymerization, copolymerization, and end-capping of poly(styryl)lithium in cyclohexane with this monomer was investigated, and it was found that a linking reaction is occuring. meta-Dimethylsilylstyrene was prepared from 3-bromostyrene in 75% yield. Anionic homopolymerization, and copolymerization of this monomer were investigated, and it was found that a more vigorous linking reaction was taking place compared to the para-substituted analog.
