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Anionic Synthesis of Well-defined Functionalized and Star-branched Polymers

Ocampo, Manuela

Abstract Details

2007, Doctor of Philosophy, University of Akron, Polymer Science.
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 w-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.
Roderic Quirk (Advisor)
230 p.

Recommended Citations

Citations

  • Ocampo, M. (2007). Anionic Synthesis of Well-defined Functionalized and Star-branched Polymers [Doctoral dissertation, University of Akron]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=akron1195606049

    APA Style (7th edition)

  • Ocampo, Manuela. Anionic Synthesis of Well-defined Functionalized and Star-branched Polymers. 2007. University of Akron, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=akron1195606049.

    MLA Style (8th edition)

  • Ocampo, Manuela. "Anionic Synthesis of Well-defined Functionalized and Star-branched Polymers." Doctoral dissertation, University of Akron, 2007. http://rave.ohiolink.edu/etdc/view?acc_num=akron1195606049

    Chicago Manual of Style (17th edition)