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dc.contributor.authorYang, Jinlian IIIen_US
dc.date.accessioned2014-03-14T20:21:43Z
dc.date.available2014-03-14T20:21:43Z
dc.date.issued1998-02-25en_US
dc.identifier.otheretd-32398-61326en_US
dc.identifier.urihttp://hdl.handle.net/10919/30440
dc.description.abstractPart I: This part of the dissertation describes a new approach to high molecular weight aromatic polyketones via soluble precursors derived from bis(a-aminonitrile)s. Bis(a-aminonitrile)s were easily synthesized from dialdehydes and secondary amines in very high yield by the Strecker reaction. Polymerization of bis(a-aminonitrile)s with activated dihalides using NaH as base in DMF yielded soluble, high molecular weight polyaminonitriles, which were hydrolyzed in acidic conditions to produce the corresponding polyketones. A novel approach to the synthesis of high molecular weight wholly aromatic polyketones without ether linkages or alkyl substituents in the polymeric backbones was demonstrated. These polyketones displayed excellent thermal properties and solvent resistance. A very efficient synthesis for diphenol and activated dihalide monomers containing keto groups was also developed based on a-aminonitrile chemistry. Novel activated dihalide monomers were obtained in quantitative yields. This method is suitable for any activated dihalide by reaction with 2 equivalents of 4-fluorobenzylaminonitrile and NaH, followed by hydrolysis to produce a new monomer with two more p-fluorobenzoyl units. For the synthesis of polyaminonitriles containing ether linkages in the polymeric backbone, only low to medium molecular weight polymers were obtained. The model studies proved that the carbanions of the aminonitriles can react with ether linkages to form more stable phenoxide anions and cause the termination of the polymerization. Part II: Functional hyperbranched poly(arylene ester)s were synthesized by thermal polymerization of 5-acetoxyisophthalic acid or 3,5-diacetoxybenzoic acid. Carboxylic terminated hyperbranched copolyesters were also synthesized by copolymerization of 5-acetoxyisophthalic acid and 3-hydroxybenzoic acid using different molar ratios of these two monomers. Both carboxylic acid and phenolic terminated hyperbranched polyesters were functionalized with different reactive groups. The carboxyl terminated hyperbranched poly(arylene ester)s were successfully used to modify inherently brittle epoxy resins. The hyperbranched polymers were chemically incorporated into the epoxy networks using triphenylphosphine (TPP) as a catalyst and 4,4'-diaminodiphenyl sulfone (DDS) as a curing agent. The chemistry and the proper formation of crosslinked networks were confirmed by solution 1H NMR, solid state CPMAS 13C NMR, kinetic FTIR spectroscopes and gel fraction analysis. Fracture toughness was improved without sacrificing thermal properties. The fracture toughness K1C values of the modified epoxies were found to be a function of the percentage loading, the molecular weights and the proportion of linear units of hyperbranched polyesters. Because the carboxylic acid terminated hyperbranched poly(arylene ester)s were immiscible with the commercially available epoxy EPON 828, the percentage loadings of hyperbranched modifiers were limited and the processibility of epoxy resins was difficult, especially at high percentage loadings of hyperbranched modifiers. These problems could be solved using phenolic terminated hyperbranched poly(arylene ester)s, which are more soluble in epoxy resins.en_US
dc.publisherVirginia Techen_US
dc.relation.haspartcover_abs_tab_of_con.pdfen_US
dc.relation.haspart1.pdfen_US
dc.relation.haspart2-3.pdfen_US
dc.relation.haspart4.pdfen_US
dc.relation.haspart5.pdfen_US
dc.relation.haspart6.pdfen_US
dc.relation.haspart7.pdfen_US
dc.relation.haspart8-9.pdfen_US
dc.relation.haspart10.pdfen_US
dc.relation.haspart11-.pdfen_US
dc.rightsI hereby grant to Virginia Tech or its agents the right to archive and to make available my thesis or dissertation in whole or in part in the University Libraries in all forms of media, now or hereafter known. I retain all proprietary rights, such as patent rights. I also retain the right to use in future works (such as articles or books) all or part of this thesis or dissertation.en_US
dc.subjectpolymerizationen_US
dc.subjectsynthesisen_US
dc.subjectpolyketonesen_US
dc.subjectaminonitrilesen_US
dc.subjectpoly(arylene ester)sen_US
dc.subjectmodificationsen_US
dc.subjecttougheningen_US
dc.subjectepoxiesen_US
dc.subjectfunctionalizationen_US
dc.subjecthyperbrancheden_US
dc.titlePart I: Synthesis of Aromatic Polyketones Via Soluble Precursors Derived from Bis(A-Amininitrile)S; Part Ii: Modifications of Epoxy Resins with Functional Hyperbranched Poly(Arylene Ester)sen_US
dc.typeDissertationen_US
dc.contributor.departmentChemistryen_US
dc.description.degreePh. D.en_US
thesis.degree.namePh. D.en_US
thesis.degree.leveldoctoralen_US
thesis.degree.grantorVirginia Polytechnic Institute and State Universityen_US
thesis.degree.disciplineChemistryen_US
dc.contributor.committeechairGibson, Harry W.en_US
dc.contributor.committeememberMcGrath, James E.en_US
dc.contributor.committeememberRiffle, Judy S.en_US
dc.contributor.committeememberDorn, Harry C.en_US
dc.contributor.committeememberTanko, James M.en_US
dc.identifier.sourceurlhttp://scholar.lib.vt.edu/theses/available/etd-32398-61326/en_US
dc.date.sdate1998-02-25en_US
dc.date.rdate1999-04-24
dc.date.adate1998-04-24en_US


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