Combination of anionic, ring -opening metathesis, living radical polymerization for novel nanostructured polymer synthesis.
Item
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Title
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Combination of anionic, ring -opening metathesis, living radical polymerization for novel nanostructured polymer synthesis.
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Identifier
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AAI3074635
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identifier
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3074635
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Creator
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Cheng, Chong.
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Contributor
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Adviser: Nan-Loh Yang
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Date
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2003
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Language
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English
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Publisher
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City University of New York.
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Subject
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Chemistry, Polymer | Chemistry, Organic
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Abstract
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Three types of living polymerization techniques---living anionic polymerization (LAP), ring-opening metathesis polymerization (ROMP), and living radical polymerization (LRP)---were investigated. Through strategic coordinations of these three techniques, a series of first syntheses of novel macroinitiators, macromonomers, and copolymers were accomplished as described below:;Nanostructured densely grafted copolymers were synthesized by combining LAP with ROMP based on 1,1-diphenylethylene (DPE) chemistry. DPE-norbornene bifunctional agent (DPE-NB) was synthesized, and selective polymerization of its norbornene functionality by ROMP yielded polyfunctional DPE-agent with quantitative DPE units. Polycarbanionic macroinitiators with quantitative initiator sites, including linear macroinitiators and a series of polystyrene-grafted macroinitiators, were synthesized by the reaction of polyfunctional DPE-agent with sec-butyllithium and poly(styryl)lithium. LAP using the linear polycarbanionic macroinitiators provided the only method till now for the synthesis of densely grafted copolymers with well-controlled long grafts (DPn up to 1000, block structures obtainable). LAP using the polystyrene-grafted polycarbanionic macroinitiators led to unique double-brush copolymers with graft junctions simultaneously carrying heterografts. Alternatively, double-brush copolymers were also prepared by macromonomer method. Norbornene-functionalized anionic monofunctional macroinitiator was synthesized by end-capping poly(styryl)lithium with DPE-NB. Novel diblock macromonomers with well-controlled short heterochains having block junctions connected to norbornene unit were synthesized by LAP using the macroinitiator. As the first homopolymerization of diblock macromonomers with non-terminal polymerizable group, ROMP of the diblock macromonomers gave poly(macromonomer)s with high conversion and controlled backbone DPn. Additionally, homopolymer-based macromonomers with a terminal norbornenyl functionality were also synthesized through LAP, and ROMP of them was also investigated.;Nanostructured grafted copolymers were also synthesized by combining LAP with LRP. Well-defined polyfunctional macroinitiators for stable free radical polymerization (SFRP) were synthesized by LAP with alkoxyamine-functionalized methacrylate. A series of well-defined grafted copolymers containing components with divergent polarities were synthesized based on SFRP using the macroinitiators.;With a wide variety of novel self-assembled nanostructures expected and a broad range of components with divergent properties obtainable, double-brush copolymers may have broad potential applications in areas including nanoparticle and nanocomposite preparation, surface and interface modification, drug and gene delivery, etc. Other types of nanostructured grafted copolymers are also expected to have various potential applications.
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Type
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dissertation
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Source
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PQT Legacy CUNY.xlsx
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degree
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Ph.D.
