Syntheses and characterization of novel copolymers.
Item
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Title
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Syntheses and characterization of novel copolymers.
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Identifier
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AAI3063899
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identifier
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3063899
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Creator
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Xu, Dayi.
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Contributor
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Adviser: Nan-Loh Yang
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Date
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2002
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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
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Abstract
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A modified Wittig reaction was developed for the synthesis of soluble electroluminescent (EL) copolymers with uniform conjugate segments separated by flexible spacers. This new method of preparing macromolecular conjugate systems has important advantages over the conventional Wittig reactions. The trans-structured conjugate segment, essential for the electroluminescent property, was obtained without the conventionally-needed follow-up step of iodine-catalyzed isomerization, which can readily lead to radical cross-linking side-reactions. In this new synthesis route, triphenylphosphine used in the conventional Wittig reaction was replaced by triethyl phosphite, leading to efficient purification of the polymer product due to the water and alcohol solubility of its by-products. Soluble EL polymers with low glass transition temperature and emission in blue and yellow were synthesized. Poly-[1,10-decanedioxy-(2,6-dimethoxy-1,4-phenylene)-1,2-ethenylene-2,3-quinoxaline-1,2-ethenylene-(3,5,-dimethoxy-1,4-phenylene)] has an absorption maximum at 375 nm and emission maximum 499 nm. Poly[1,10-decanedioxy-(2,6-dimethoxy-1,4-phenylene)-1,2-ethenylene-9,10-anthracene-1,2-ethenylene-(3,5,-dimethoxy-1,4-phenylene)] has an absorption maximum at 416 nm and emission maximum at 566 nm. These EL polymers were characterized using methods including one and two dimensional NMR, photoluminescence and DSC.;Three categories of functionalized polystyrene having electric charge, dipole, and hydrogen bond forming ability were synthesized. Polystyrenes sulfonated at a range of 2 to 30% were prepared to give surface with charge densities up to 0.15 C/m2; the negatively charged polymer has the attributes to serve as a model extracellular matrix for protein adsorption and organization to gain fundamental information on tissue engineering. Acetylated polystyrene with dipole and polystyrene with hydroxyl group for interfacial hydrogen-bonding were synthesized for studies on interface including fracture toughness at polymer interfaces.;Random copolymers of methyl methacrylate and 3-(3, 5,7, 9, 11, 13, 15-heptacyclopentylpentacyclo [9. 5. 1.3,9. 1 5,15 .1 7,13] octasiloxa-1-nyl) propyl methacrylate (POSS-propyl methacrylate) were synthesized for the first time using atom transfer radical polymerization, resulting in narrow molecular weight distribution. This copolymer has the capability to serve as a very efficient compatibilizer for polystyrene/poly (methyl methacrylate) immiscible blend.
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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.
