KOPS - Das Institutionelle Repositorium der Universität Konstanz

Nematic and cholesteric thermotropic polyesters with azoxybenzene mesogenic units and flexible spacers in the main chain

Nematic and cholesteric thermotropic polyesters with azoxybenzene mesogenic units and flexible spacers in the main chain

Zitieren

Dateien zu dieser Ressource

Prüfsumme: MD5:10ed8c99f06e7496b4ee66ff1578200f

BLUMSTEIN, Alexandre, S. VILASAGAR, S. PONRATHNAM, Stuart B. CLOUGH, Rita B. BLUMSTEIN, Georg MARET, 1982. Nematic and cholesteric thermotropic polyesters with azoxybenzene mesogenic units and flexible spacers in the main chain. In: Journal of Polymer Science: Polymer Physics Edition. 20(5), pp. 877-892. ISSN 0098-1273

@article{Blumstein1982Nemat-27458, title={Nematic and cholesteric thermotropic polyesters with azoxybenzene mesogenic units and flexible spacers in the main chain}, year={1982}, doi={10.1002/pol.1982.180200510}, number={5}, volume={20}, issn={0098-1273}, journal={Journal of Polymer Science: Polymer Physics Edition}, pages={877--892}, author={Blumstein, Alexandre and Vilasagar, S. and Ponrathnam, S. and Clough, Stuart B. and Blumstein, Rita B. and Maret, Georg} }

<rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#" xmlns:bibo="http://purl.org/ontology/bibo/" xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:dcterms="http://purl.org/dc/terms/" xmlns:xsd="http://www.w3.org/2001/XMLSchema#" > <rdf:Description rdf:about="https://kops.uni-konstanz.de/rdf/resource/123456789/27458"> <dcterms:available rdf:datatype="http://www.w3.org/2001/XMLSchema#dateTime">2014-04-14T13:19:28Z</dcterms:available> <dcterms:title>Nematic and cholesteric thermotropic polyesters with azoxybenzene mesogenic units and flexible spacers in the main chain</dcterms:title> <dcterms:bibliographicCitation>Journal of Polymer Science / Polymer physics Edition ; 20 (1982), 5. - S. 877-892</dcterms:bibliographicCitation> <dc:contributor>Blumstein, Rita B.</dc:contributor> <dcterms:rights rdf:resource="http://nbn-resolving.org/urn:nbn:de:bsz:352-20140905103605204-4002607-1"/> <dc:language>eng</dc:language> <dc:creator>Maret, Georg</dc:creator> <dc:contributor>Clough, Stuart B.</dc:contributor> <dc:creator>Vilasagar, S.</dc:creator> <dc:contributor>Blumstein, Alexandre</dc:contributor> <dc:date rdf:datatype="http://www.w3.org/2001/XMLSchema#dateTime">2014-04-14T13:19:28Z</dc:date> <bibo:uri rdf:resource="http://kops.uni-konstanz.de/handle/123456789/27458"/> <dc:creator>Clough, Stuart B.</dc:creator> <dc:creator>Ponrathnam, S.</dc:creator> <dc:creator>Blumstein, Rita B.</dc:creator> <dc:contributor>Vilasagar, S.</dc:contributor> <dcterms:issued>1982</dcterms:issued> <dc:creator>Blumstein, Alexandre</dc:creator> <dc:rights>deposit-license</dc:rights> <dc:contributor>Ponrathnam, S.</dc:contributor> <dcterms:abstract xml:lang="eng">Properties of linear polyesters based on azoxybenzene and 2,2′-methylazoxybenzene moieties with linear, flexible spacers based on mixtures of dodecanedioic acid (DDA) and methyladipic acid (MAA), chiral or racemic, of various compositions (system MAA/DDA-8 and MAA/DDA-9, respectively) have been described. Substitution of methyl groups in the 2,2′ or 3,3′ positions of the mesogenic core leads to soluble and relatively low-melting-point polyesters. The viscosity law for (MAA/DDA-9) polyesters in 1,1,2,2 tetrachloroethane gives an exponent 0.76, indicating well-sol-vated, coiled chain conformations in dilute solution. Calorimetric data show an increase in isotropization entropy ΔSNI with increasing average length of the spacer. This suggests a nonrandom conformation of the spacer in the nematic melt with a degree of order superior to that of low-molecular-weight analogs. X-ray data obtained with an oriented nematic glass quenched from the nematic melt of DDA-9 subjected to a magnetic field of 10–12 T also support the extended-chain model in the nematic phase of DDA-9. Oriented fibers can be produced by subjecting nematic melts of polyesters 8 and 9 either to magnetic fields of high intensity or to shear fields. The x-ray data obtained from these fibers also support the extended-chain model. Cholesteric systems do not orient in the magnetic field of 10–12 T. The study of mesophases of systems 8 and 9 indicates a dramatic influence of the position of the ester group on the stability of the mesophase in the azoxybenzene polyesters. The results are interpreted in terms of geometric factors influencing the colinearity of the mesogenic core and of the extended spacer.</dcterms:abstract> <dc:contributor>Maret, Georg</dc:contributor> </rdf:Description> </rdf:RDF>

Dateiabrufe seit 01.10.2014 (Informationen über die Zugriffsstatistik)

Blumstein_274581.pdf 112

Das Dokument erscheint in:

KOPS Suche


Stöbern

Mein Benutzerkonto