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dc.contributor.authorFratini, Christopher M.en_US
dc.date.accessioned2014-03-14T20:10:38Z
dc.date.available2014-03-14T20:10:38Z
dc.date.issued2006-04-14en_US
dc.identifier.otheretd-04242006-105009en_US
dc.identifier.urihttp://hdl.handle.net/10919/27211
dc.description.abstractThe development of a new catalyst system by The Dow Chemical Company has resulted in the production of isotactic polypropylene and propylene/ethylene copolymers with a unique defect and comonomer distribution. This work investigated the morphology and optical properties of cast and compression molded films made from the homopolymer and copolymers with up to 20 mol% ethylene comonomer. The defect distribution of the Dow Chemical copolymers resulted in materials with lower crystallinity than Ziegler-Natta or metallocene-made materials of similar ethylene content. These materials exhibited a gamma-phase crystal content ranging from 0-95%, depending on ethylene content, processing condition, and catalyst type. The gamma-phase crystal content of quiescently crystallized copolymer films was found to significantly influence their bulk optical properties, presumably through a change in the spherulite birefringence. The bulk haze, clarity, and transparency of a homopolymer film were degraded through annealing treatments, which decreased the fraction of gamma-phase crystallinity and increased the thickness of existing lamellae, resulting in an increased intensity of scattered light and a corresponding degradation in the optical properties of the film. The haze, clarity, transparency, and gloss of the copolymer films were found to improve at higher comonomer content and higher cooling rates. The variation in the length scale and degree of disorder in the bulk morphology of films processed under different conditions was shown to correlate with the optical quality of the films, with smaller scale morphologies scattering less light and resulting in films with better optical properties. It was also shown that no single metric can completely describe the optical quality of a polymer film; the relative importance of haze, transparency, and gloss, which depends on the intended application of the film, was discussed. The influence of surface scattering from the films was controlled through the compression molding of films using substrates of different surface roughness. The contribution of light scattered from the surface of the films was isolated and found to play a significant role in the degradation of optical quality.en_US
dc.publisherVirginia Techen_US
dc.relation.haspartphd_thesis.pdfen_US
dc.rightsIn Copyrighten
dc.rights.urihttp://rightsstatements.org/vocab/InC/1.0/en
dc.subjectMorphologyen_US
dc.subjectClarityen_US
dc.subjectLight Scatteringen_US
dc.subjectGlossen_US
dc.subjectTransparencyen_US
dc.subjectHazeen_US
dc.subjectSurface Roughnessen_US
dc.subjectFilmen_US
dc.subjectCopolymeren_US
dc.subjectPolypropyleneen_US
dc.titleStudy of the Morphology and Optical Properties of Propylene/Ethylene Copolymer Filmsen_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.committeechairMarand, Hervé L.en_US
dc.contributor.committeememberWard, Thomas C.en_US
dc.contributor.committeememberGibson, Harry W.en_US
dc.contributor.committeememberWilkes, Garth L.en_US
dc.contributor.committeememberEsker, Alan R.en_US
dc.identifier.sourceurlhttp://scholar.lib.vt.edu/theses/available/etd-04242006-105009/en_US
dc.date.sdate2006-04-24en_US
dc.date.rdate2007-05-04
dc.date.adate2006-05-04en_US


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