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X-ray structure analysis of liquid crystalline copoly(ester carbonates)

Schneider, Andrea-Ingrid
http://rave.ohiolink.edu/etdc/view?acc_num=case1059570165

Abstract Details

1991, Doctor of Philosophy, Case Western Reserve University, Macromolecular Science.
X-ray diffraction methods have been used to investigate the solid-state structure of wholly aromatic main chain liquid crystalline copoly(ester carbonates) and copolyesters incorporating kinked units. The second chapter deals with the copolymers of p-hydroxy benzoic acid (HBA), hydroquinone (HQ) and carbonate units (CO), of HBA, HQ and isophthalic acid (IPA) and of HBA, resorcinol (RC) and terephthalic acid (TPA). The x-ray fiber diagrams for the three systems show that the copoly(ester carbonates) have the highest degree of order. Chapters 3 through 5 deal primarily with the copoly(ester carbonate) of 75/25/25 HBA/HQ/CO, which has been studied in more detail. As a first step the one-dimensional structure was determined for the chain direction. The x-ray fiber diagram show the occurrence of non-periodic meridional peaks with d-spacings of 6.47, 3.22, 2.15 and 2.05A, which can be reproduced by calculating the scattering of chains with a random sequence distribution of the monomers along the chain axis. In a second step the three-dimensional structure was determined. It is found that a pseudo-dimer must be assumed in order to generate all the observed layer lines. In the as-spun fibers, the chains are packed in an orthorhombic unit cell with the base plane dimensions a = 5.0A and b = 8.9A. T he discrete equatorial and off-equatorial Bragg maxima arise as a consequence of packing of the chains with a very limited off-register between adjacent chains. Register in the arrays of chains is achieved when the linkage units, ester or carbonate, lie in a specific plane perpendicular to the chain axis. The last chapter deals with the modelling of discrete systems using the SYBYL°ler and CERIUS software packages. The carbonate units were found to have all possible values of distortion between cis-trans, trans-trans and trans-cis, with a 60° maximum deviation from chain direction. (Abstract shortened with permission of author.)
John Blackwell (Advisor)
204 p.
Chemistry, Polymer
X-ray, structure analysis; Liquid crystalline copolyester

Recommended Citations

Citations

  • Schneider, A.-I. (1991). X-ray structure analysis of liquid crystalline copoly(ester carbonates) [Doctoral dissertation, Case Western Reserve University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=case1059570165

    APA Style (7th edition)

  • Schneider, Andrea-Ingrid. X-ray structure analysis of liquid crystalline copoly(ester carbonates). 1991. Case Western Reserve University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=case1059570165.

    MLA Style (8th edition)

  • Schneider, Andrea-Ingrid. "X-ray structure analysis of liquid crystalline copoly(ester carbonates)." Doctoral dissertation, Case Western Reserve University, 1991. http://rave.ohiolink.edu/etdc/view?acc_num=case1059570165

    Chicago Manual of Style (17th edition)

case1059570165
504
© 1991, all rights reserved.
This open access ETD is published by Case Western Reserve University School of Graduate Studies and OhioLINK.