Fourier transform infrared studies of semicrystalline trans-1,4-polyisoprene.
Item
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Title
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Fourier transform infrared studies of semicrystalline trans-1,4-polyisoprene.
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Identifier
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AAI9000025
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identifier
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9000025
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Creator
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Gavish, Michal.
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Contributor
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Adviser: Arthur E. Woodward
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Date
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1989
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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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The semicrystalline structure of trans-1,4-polyisoprene (TPI) lamellas was studied by FTIR spectroscopy. The crystalline and amorphous components of the spectrum were separated and assigned. The crystalline component was assigned for both the monoclinic (alpha) and the orthorhombic (beta) forms using normal coordinate calculations for a single chain. The calculations for the two crystal forms were compared and a correlation was found between both their frequencies and potential energy distribution. Each band in the beta spectrum was correlated to a singlet or a doublet in the alpha spectrum. Correlation of each band in the spectra of the two crystalline forms with the amorphous spectrum was then used to assign the infrared bands of the latter. Conformational assignment for the different components of some of the amorphous bands were obtained using samples at different temperatures above the crystalline melting point.;Infrared studies of partially modified TPI lamellas were carried out. TPI lamellas were reacted in suspension so that the surfaces were modified and the crystalline cores remained unchanged. The reactions used were epoxidation, hydrochlorination and hydroxylation of the double bond. The infrared spectra of the modified surface were obtained and tentative assignment of the bands was made.;FTIR spectra of TPI were used to develop a method for the direct measurement of sample crystallinity. The effect of temperature on the lamellar structure was also studied and the sample crystallinity was found to increase by about 10% upon cooling from room temperature to {dollar}-{dollar}30{dollar}\sp\circ{dollar}c. The spectra also indicated changes with temperature in the crystalline interchain distances.
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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.
