Synthesis and characterization of high performance polytetrahydrofuran based polyurethane-urea and ionene elastomers

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dc.contributor.authorLee, Binen
dc.contributor.committeechairMcGrath, James E.en
dc.contributor.committeememberDwight, David W.en
dc.contributor.committeememberReifsnider, Kenneth L.en
dc.contributor.committeememberWilkes, Garth L.en
dc.contributor.committeememberWolfe, James F.en
dc.contributor.departmentMaterials Engineering Scienceen
dc.date.accessioned2017-11-09T21:42:10Zen
dc.date.available2017-11-09T21:42:10Zen
dc.date.issued1987en
dc.description.abstractIn this thesis, the effect of interphase bonding on the cohesiveness of domain structure was addressed. The interchain attractive forces between rigid segments and the phase separation between hard and soft segments have been improved by introducing either urea groups or ionic units. The urea linkages have the possibility of extensive hydrogen bonding while ionic units interact with each other by coulombic interactions, which provide even stronger interchain associations than the hydrogen bonding effects. This thesis addressed the preparation and characterization of polytetrahydrofuran based segmented polyurethane-urea and ionene elastomers. The urea linkages were effectively introduced to the polyurethane elastomers through an unconventional route which was based on carbamate-isocyanate interactions. The carbamates were generated principally from isocyanate functional prepolymers and tertiary alcohols. The carbamates were rearranged thermally and/or catalytically to produce amines which were rapidly converted to ureas. The effects of varying the size of the rigid and flexible segments in polyurethane elastomers on physical behavior were investigated. The importance of hydrogen bonding interactions in promoting phase separation of hard and soft segments and the cohesiveness of hard segment domain structure was demonstrated. Living, difunctional polytetrahydrofuran dioxonium ions were prepared via triflic anhydride initiation. The direct coupling of these "living" polytetrahydrofuran dioxonium ions with a ditertiary amine was used to produce a novel segmented ionene elastomer. The ionenes thus synthesized displayed interesting solution behavior and could be molded, or cast to produce good physical properties. Photochromic as well as thermochromic phenomena were also noticed in these systems.en
dc.description.degreePh. D.en
dc.format.extentxix, 298 leavesen
dc.format.mimetypeapplication/pdfen
dc.identifier.urihttp://hdl.handle.net/10919/80277en
dc.language.isoen_USen
dc.publisherVirginia Polytechnic Institute and State Universityen
dc.relation.isformatofOCLC# 16882869en
dc.rightsIn Copyrighten
dc.rights.urihttp://rightsstatements.org/vocab/InC/1.0/en
dc.subject.lccLD5655.V856 1987.L438en
dc.subject.lcshThermoplasticsen
dc.subject.lcshElastomersen
dc.subject.lcshPolyurethanesen
dc.titleSynthesis and characterization of high performance polytetrahydrofuran based polyurethane-urea and ionene elastomersen
dc.typeDissertationen
dc.type.dcmitypeTexten
thesis.degree.disciplineMaterials Engineering Scienceen
thesis.degree.grantorVirginia Polytechnic Institute and State Universityen
thesis.degree.leveldoctoralen
thesis.degree.namePh. D.en

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